Maxillary Sinus Anatomy, Pathology, and Graft Surgery










987
37
Maxillary Sinus Anatomy,
Pathology, and Graft
Surgery
RANDOLPH R. RESNIK AND CARL E. MISCH
T
he posterior maxilla has been described as one of the most
challenging and complex intraoral regions that confronts
the implant clinician. ere exist many treatment planning
and patient factors that contribute to these problems in this area,
which in many cases require the clinician to have additional train-
ing and an increased skill set:
• Poorbonedensity
• Compromisedavailablebone
• Increasedpneumatizationofthemaxillarysinus
• Increasedcrownheightspace
• Ridgepositionshiftstowardlingual(medial)
• Dicultaccessbecauseofanatomiclocation
• Increasedbitingforce
• Requirementofwiderdiameterimplantsandincreasednumber
Before discussing the various treatment options of the pos-
terior maxilla, it is imperative that the implant clinician have a
strong foundation for maxillary sinus anatomy, anatomic variants,
pathology, and a comprehensive understanding of the various
treatment approaches.
Maxillary Sinus Anatomy
e maxillary sinuses were rst illustrated and described by Leonardo
DaVinciin1489andlaterdocumentedbytheEnglishanatomist
Nathaniel Highmore in 1651.
1
e maxillary sinus, or antrum of
Highmore, lies within the body of the maxillary bone and is the larg-
estandrsttodevelopoftheparanasalsinuses(Fig.37.1).Adultmax-
illary sinuses are pyramid-shaped, air-lled cavities that are bordered
by the nasal cavity. ere is much debate about the actual function
ofthe maxillarysinus.Possibletheorizedrolesofthe sinusinclude
weight reduction of the skull, phonetic resonance, participation of
warminghumidicationofinspiredair,andolfaction.Abiomechani-
cal adaptation of the maxillary sinus directs forces away from the orbit
and cranial cavity when a force is delivered to the midface.
Development and Expansion of the Maxillary
Sinus
Aprimarypneumatizationoccursatapproximately3monthsof
fetal development by an outpouching of the nasal mucosa within
theethmoidinfundibulum.Atthattime,themaxillarysinusisa
bud situated at the infralateral surface of the ethmoid infundibu-
lumbetweentheupperandmiddlemeatus.Prenatally,asecond-
arypneumatizationoccurs.Atbirth,thesinusisstillanoblong
groove on the mesial side of the maxilla just above the germ of the
rst deciduous molar.
2
Atbirth,thesinuscavitiesarelledwithuid.Postnatallyand
until the child is 3 months old the growth of the maxillary sinus is
closelyrelatedtothepressureexertedbytheeyeontheorbitoor,
the tension of the supercial musculature on the maxilla, and
theformingdentition.Astheskullmatures,thesethreeelements
inuenceitsthree-dimensional(3D)development.At5months,
the sinus appears as a triangular area medial to the infraorbital
foramen.
3
Duringthechild’srstyear,themaxillarysinusexpandslat-
erally underneath the infraorbital canal, which is protected by
a thin bony ridge. e antrum grows apically and progressively
replaces the space formerly occupied by the developing dentition.
egrowthinheightisbestreectedbytherelativepositionof
thesinusoor.At12yearsofage,pneumatizationextendstothe
planeofthelateralorbitalwall,andthesinusoorislevelwith
theoorofthenose.Duringlateryears,pneumatizationspreads
inferiorly as the permanent teeth erupt. e adult sinus has a vol-
umeofapproximately15mL(34mmheightx33lengthx23mm
width).emaindevelopmentoftheantrumoccursastheper-
manentdentitioneruptsandpneumatizationextendsthroughout
thebodyofthemaxillaandthemaxillaryprocessofthezygomatic
bone.Extensionintothealveolarprocesslowerstheoorofthe
sinusapproximately5mm.Anteroposteriorly,thesinusexpansion
corresponds to the growth of the midface and is completed only
with the eruption of the third permanent molars when the young
personisabout16to18yearsofage.
4
Intheadult,thesinusispyramidshapedwithconsistingoffour
bony walls, the base of which faces the lateral nasal wall and the
apexofwhichextendstowardthezygomaticbone(Fig. 37.2).e
oorofthemaxillarysinuscavityisreinforcedbybonyormem-
branous septa, joining the medial or lateral walls with oblique or
transverse buttress-like webs. ey develop as a result of genetics
and stress transfer within the bone over the roots of teeth. ese
have the appearance of reinforcement webs in a wooden boat and

988
PART VII Soft and Hard Tissue Rehabilitation
rarely divide the antrum into separate compartments. ese ele-
ments are present from the canine to the molar region and tend to
disappear in the maxilla of the long-term edentulous patient when
stresses to the bone are reduced. Karmody found that the most
common oblique septum is located in the superior anterior corner
ofthesinusorinfraorbitalrecess(whichmayexpandanteriorlyto
thenasolacrimalduct).
5
e medial wall is juxtaposed with the
middle and inferior meatus.
Althoughthemaxillary sinus maintains its overallsizewhile
the teeth are present, an expansion phenomenon of the maxil-
lary sinus occurs with the loss of posterior teeth.
6
e antrum
expands in both inferior and lateral dimensions. is expansion
may even invade the canine eminence region and proceed to the
lateral piriform rim of the nose. e dimension of available bone
height of the posterior maxilla is greatly reduced as a result of dual
resorptionfromthecrestoftheridgeandpneumatizationofthe
sinus after the loss of teeth. e sinus expansion is more rapid than
thecrestalboneheightchanges.Asaresultoftheinferiorsinus
expansion, the amount of available bone in the posterior maxilla
greatlydecreasesinheight(Fig. 37.3).emaxillarysinustends
to enlarge with age, as well as with edentulism, which further
11
2
3
4
Fig. . Maxillary sinus (1) is the largest of the four paranasal sinuses.
The initial maxillary sinus formation is completed at age 16 to 18 years. 2,
Frontal sinus; 3, ethmoid sinus; 4, sphenoid sinus.
Orbit
Middle
meatus
Maxillary
sinus
at birth
Maxillary
sinus
evolution
Tooth
Sphenoethmoidal sinus
Frontal
sinus
Crista
galli
Superior
meatus
Frontonasal
dura
Nasal
septum
Nasal
fossa
Inferior
meatus
Fig. . Maxillary sinus begins to form in the fetus and by 5 months is the size of a pea, under the
eye, and close to the ostium for drainage. By 16 years of age, the maxillary sinus has four thin, bony walls
around it. The superior wall separates it from the floor of the orbit. The medial wall contains the ostium to
drain the sinus and separates it from the nasal fossa. The lateral wall forms the maxillary bone below the
zygomatic arch. The floor of the antrum rests above the roots of the teeth.

989
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
decreasestheamountofavailablebone.Inadditiontothedimin-
ished quantity, bone in the posterior maxilla often is softer and of
poorerquality.Radiographstypicallyrevealsparsetrabeculations,
and the tactile experience of drilling in this bone resembles a Sty-
rofoamtypeofmaterial(D4Bone).
Afternormalsinusexpansion,withperiodontaldiseaseandtooth
loss increasing the bone loss, inadequate bone will result between
thealveolarridgecrestandtheoorofthemaxillarysinus.Inmost
cases, bone quantity will be compromised for implant placement.
e limited available bone is compounded by a decrease in bone
density and the shifting of the residual ridge in a medial direction.
erefore this area of the maxilla is often reported with an increased
incidence of implant malpositioning and morbidity.
Bone Resorption Process
e maxilla generally has a thinner cortical plate facially compared
with any region of the mandible, and very minimal cortical bone is
presentontheridge.Inaddition,thetrabecularboneintheposterior
maxillaisner(lessdense)thanotherdentateregions.Whenmaxil-
lary posterior teeth are lost, an initial decrease in bone width at the
expense of the labial bony plate results. e width of the posterior
maxilla has been shown to decrease at a more rapid rate than in any
other region of the jaws.
7
e resorption phenomenon is accelerated
bythelossofvascularizationofthealveolarboneandtheexisting
ne trabecular bone type. However, because the initial residual ridge
is inherently wide in the posterior maxilla, even with a signicant
decrease in the width of the ridge, adequate-diameter root-form
implants(5mm)usually canbeplaced. However, astheresorp-
tion process continues, the residual ridge continues to progressively
shift toward the palate until the ridge is signicantly resorbed into a
medially positioned narrower bone volume.
8
is results in the buc-
cal cusp and central fossa of the nal restoration being cantilevered
facially to satisfy esthetic requirements at the expense of biomechan-
ics in the moderate to severe atrophic ridges. is cantilevered part
of the prosthesis is usually in the form of a ridge lap pontic area,
whichinmostcasesresultsinhygienediculties.
Resultant Poor Bone Density
Ingeneral,thebonequalityis poorestinthe posteriormax-
illa, compared with any other intraoral region.
9
A literature
review of clinical studies reveals that the poorest bone density
maydecreaseimplantloadingsurvivalbyanaverageof16%,
andithasbeenreportedaslowas40%.
10
e cause of these
failures is related to several factors. Bone strength is directly
related to its density, and the poor-density bone of this region
isoften5to10timesweaker,comparedwithbonefoundinthe
anteriormandible.Bonedensitiesdirectlyinuencethebone-
to-implantcontactpercentage(BIC),whichaccountsforthe
forcetransmissiontothebone.eBICisleastinD4bone,
and the stress patterns in this bone migrate farther toward the
apexoftheimplant(Fig.37.4).Asaresult,bonelossismore
pronounced and also occurs along the implant body, rather
than only crestally, as in other denser bone conditions. D4
bone also exhibits the greatest biomechanical elastic modulus
dierence compared with titanium under load.
11
Earlierstud-
ies and surgical protocols did not take into consideration the
poorBICinthisarea.
Intheposteriormaxilla,thedecientosseousstructuresand
an absence of cortical plate on the crest of the ridge is often
observed, which further compromises the initial implant stabil-
ity at the time of insertion. e labial cortical plate is thin, and
theridgeisoftenwide.Asaresult,thelateralcorticalBICtosta-
bilizetheimplantisofteninsignicant.eimplantplacement
protocoloftenusesbonecompression(osseodensication)rather
thanboneextraction(removal)tocreatetheimplantosteotomy
tocompensateforthesedeciencies.Ifthesurgicalprotocolis
notmodied,theinitialhealingofanimplantinD4bonewill
be compromised.
1
2
3
3
3
4
AB
Fig. . (A) The fourth expansion phenomenon of the maxillary sinus occurs with the loss of the poste-
rior teeth. The anterior portion of the sinus may expand to the piriform rim of the nose. The inferior expan-
sion may approach the crest of the ridge. 1, Maxillary sinus; 2, frontal sinus; 3, ethmoid sinus; 4, sphenoid
sinus. (B) Coronal section of the posterior region of the edentulous human maxilla. Note expansion of
the sinus floor inferiorly far below the level of the floor of the nose. The alveolar ridge bone is markedly
atrophied, whereas the ridge submucosa has become fibrotic. Stained with Rescorcin Fuchsin stain and
counterstained with Ban Gieson. (Courtesy Mohamed Sharawy, Augusta, Georgia.)

990
PART VII Soft and Hard Tissue Rehabilitation
Bony Walls
e maxillary sinus features six bony walls, each of which contain
important anatomic structures that play a signicant role in the
treatment of the maxillary posterior region. e implant clinician
must have a strong understanding and foundation of the bony
walls associated with the posterior maxilla in the preoperative
assessmentbeforesurgicalprocedures(Fig.37.5)
Anterior Wall
e anterior wall of the maxillary sinus consists of thin, compact
bone extending from the orbital rim to just above the apex of
thecuspid.Withthelossofthecanine,theanteriorwallofthe
antrummayapproximatethecrestoftheresidualridge.Within
theanteriorwallandapproximately6to7mmbelowtheorbital
rim,withanatomicvariantsasfaras14mmfromtheorbitalrim,
is the infraorbital foramen (Fig. 37.6A). e infraorbital nerve
runs along the roof of the sinus and exits through the foramen.
e infraorbital blood vessels and nerves lie directly on the supe-
rior wall of the maxillary sinus and within the sinus mucosa.
Tenderness to pressure over the infraorbital foramen or redness
oftheoverlyingskinmayindicateinammationofthesinusmem-
brane from infection or trauma, which may contraindicate graft
surgeryuntilresolution.Inpatientsexhibitinganatomicvariants
of the infraorbital foramen, neurosensory impairment may occur
during retraction of this area, leading to neurapraxia type injuries.
e use of worn, sharp-edged retractors should be avoided when
reectingtissuesuperiorlyinthisareatoavoidpotentialinjuries.
Within the anterior wall of the sinus, the thinnest part is the
canine fossa, which is directly above the canine tooth. e anterior
wall of the maxillary sinus may also serve as surgical access during
Caldwell-Lucprocedurestotreatapreexistingorpost–sinusgraft,
pathologic condition.
Superior Wall
e superior wall of the maxillary sinus coincides with the thin
inferiororbitaloor.eorbitaloorslantsinferiorlyinamedio-
lateral direction and is convex into the sinus cavity.
Abonyridgeisusuallypresentinthiswallthathousestheinfra-
orbital canal, which contains the infraorbital nerve and associated
bloodvessels.Dehiscenceofthebonychambermaybepresent,
resulting in direct contact between the infraorbital structures and
the sinus mucosa.
Ocular symptoms may result from infections or tumors in the
superior aspects of the sinus region and may include proptosis
(bulging of the eye) and diplopia (double vision). When these
problems occur, the patient is closely supervised, and a medical
consult is advised to decrease the risk of severe complications that
may result from the spread of infection in a superior direction.
Superior-spreading infections may lead to signicant ocular prob-
lemsorbrainabscesses.Asaresult,whenocularorcerebralsymp-
toms appear, aggressive therapy to decrease the spread of infection
is indicated. Overpacking the maxillary sinus with bone graft
material during a sinus graft may result in pressure against the
superiorwallifasinusinfectiondevelops(seeFig.37.6B).
Posterior Wall
e posterior wall of the maxillary sinus corresponds to the
pterygomaxillary region, which separates the antrum from the
infratemporal fossa. e posterior wall usually has several vital
structures in the region of the pterygomaxillary fossa, including
the internal maxillary artery, pterygoid plexus, sphenopalatine
ganglion, and greater palatine nerve. e posterior wall should
always be identied radiographically because when the wall is not
present,apathologiccondition(includingneoplasms)istobesus-
pected(seeFig.37.6C).
Commondonorsitestoobtainautogenousboneforsinusaug-
mentation procedures include the tuberosity area. Special consid-
eration should be taken for the posterior extent of the tuberosity
removal. Aggressivetuberosity removalmay lead to bleeding in
theinfratemporalfossa(pterygoidplexus),resultinginlife-threat-
ening situations.
It should be noted that pterygoid implants placed through
the posterior sinus wall and into this region may approach vital
structures,includingthemaxillaryartery.Ablindsurgicaltech-
nique to place a pterygoid implant through the posterior wall may
have increased surgical risk. However, they are of benet primarily
Fig. . Bone–implant contact percent is often reduced in the posterior
maxilla because the quality of bone is poorer than other regions of the
mouth. This histologic slide depicts the numerous areas of no bone con-
tact at the implant interface.
Fig. . Maxillary sinus is comprised of six walls that contain significant
anatomic and vital structures, which are important in the placement of
implants. 1, Lateral, 2, anterior, 3, medial, 4, posterior, 5, inferior, 6, superior.

991
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
when third or fourth molars are needed for prosthetic reconstruc-
tion or sinus grafts are contraindicated and available bone poste-
rior to the antrum is present.
Medial Wall
e medial wall of the antrum coincides with the lateral wall of
the nasal cavity and is the most complex of the various walls of the
sinus. On the nasal aspect, the lower section of the medial wall
parallelsthelowermeatusandoorofthenasalfossa;theupper
aspect corresponds to the middle meatus. e medial wall is usu-
allyverticalandsmoothontheantralside(seeFig.37.6D).
e main drainage avenue of the maxillary sinus is through the
maxillary ostium. e primary ostium is located in the superior
aspect of the sinus medial wall and drains its secretions via the
ethmoid infundibulum through the hiatus semilunaris into the
middle meatus of the nasal cavity. e infundibulum is approxi-
mately5to10mmlonganddrainsviaciliaryactioninasuperior
andmedialdirection.eostiumdiameteraverages2.4mmin
health;however,pathologicconditionsmayalterthesizetovary
from1to17mm.
12
e maxillary ostium and infundibulum are part of the ante-
rior ethmoid middle meatal complex, the region through which
AA B
C
EF
D
Fig. . Six bony walls of the maxillary sinus. (A) Anterior. (B) Superior. (C) Posterior. (D) Medial. (E)
Lateral. (F) Inferior.

992
PART VII Soft and Hard Tissue Rehabilitation
the frontal and maxillary sinuses drain, which is primarily respon-
sible for mucociliary clearance of the sinuses to the nasopharynx.
Asaresult,obstructioninoneormoreareasofthecomplexwill
usually result in rhinosinusitis or lead to morbidity of the graft or
implant.Patencyofthemaxillaryostiumismostcrucialpreop-
eratively and postoperatively during maxillary graft sinus surgery
to preventinfection and morbidity of the graft. Evaluatingthe
patencyoftheostiumviaconebeamcomputerizedtomography
(CBCT) is easily accomplished with evaluation of serial cross-
sectional images. e patency of the ostium must be ascertained
before surgery to prevent or minimize postoperative complica-
tions. is is easily veried via coronal or cross-sectional images
on CBCT surveys. Of utmost importance when performing
any procedure involving the maxillary sinus, the patency of the
ostium must be maintained throughout the postoperative period.
If ostium patency is compromised, increased morbidity of the
implant or graft will occur because the mucociliary action of the
maxillary sinus will be compromised.
Smaller, accessory or secondary ostia may be present that are
usually located in the middle meatus posterior to the main ostium.
ese additional ostia are most likely the result of chronic sinus
inammationandmucousmembranebreakdown.eyarepres-
ent in approximately 30% of patients, ranging from a fraction
ofamillimeterto0.5cm,andarecommonlyfoundwithinthe
membranous fontanelles of the lateral nasal wall.
13
Fontanelles are
usuallyclassiedeitherasanteriorfontanelles(AFs)orposterior
fontanelles(PFs)andaretermedbytheirrelationtotheuncinated
process. ese weak areas in the sinus wall are sometimes used to
create additional openings into the sinus for treatment of chronic
sinusinfections.Primaryandsecondaryostiamay,onoccasion,
combine and form a large ostium within the infundibulum.
Lateral Wall
e lateral wall of the maxillary sinus forms the posterior max-
illaandthezygomaticprocess.iswallvariesgreatlyinthick-
ness from several millimeters in dentate patients to less than 1
mminanedentulouspatient.ACBCTexaminationwillreveal
the osseous thickness of the lateral wall, which is crucial in den-
ing the osteotomy location and preparation technique. Patients
exhibiting increased parafunction forces will have thicker lateral
walls (see Fig.37.6E). e lateral wall thickness of the maxilla
has been noted to be extremely variable, with some cases being
nonexistent. is will lead to an increased possibility of membrane
perforation,evenoccurringonreection.Incontrast,thelateral
wall may be very thick, which is usually seen with patients that
exhibit parafunction and have just recently lost the posterior teeth.
Inthese situations, lateral wallsinusgraftingbecomes verydif-
cult because of the cortical thickness. e lateral wall houses the
intraosseous anastomosis of the infraorbital and posterior superior
alveolar artery, which may lead to a bleeding complication because
this area is the site for osteotomy preparation of the lateral wall
sinus graft procedure.
Inferior Wall
einferiorwalloroorofthemaxillarysinusisincloserelation-
ship with the apices of the maxillary molars and premolars. e
teeth usually are separated from the sinus mucosa by a thin layer
ofbone;however,onoccasion,teethmayperforatetheoorofthe
sinus and be in direct contact with the sinus lining. Studies have
shown that the rst molar has the most common dehiscent tooth
root,occurringuptoapproximately30%to40%ofthetime.
14
Indentatepatientsthesinusoorisapproximatelyatthelevelof
thenasaloor.Intheedentulousposteriormaxillathesinusoor
isoften1cmbelowthelevelofthenasaloor(seeFig.37.6F).
Radiographically,thesinusinferioroormorphologyiseasily
seenvia3Dimaging.eoorisrarelyatandsmooth;thepres-
ence of irregularities and septa should be determined and their
exact locations noted. Irregularoors are most often seen after
teeth are extracted, leaving residual bony crests that increase risk
ofperforationbecauseofthe dicultyinmembrane reection.
Insomecases,thebonycrestsarenotevenseen onthe CBCT
evaluation.
Complete or incomplete bony septa may exist on the oor
inaverticalorhorizontalplane.Approximately30%ofdentate
maxillae have septa, with three-fourths appearing in the premo-
lar region. Complete septa separating the sinus into compart-
mentsareveryrare,occurringinonly1.0%to2.5%ofmaxillary
sinuses.
15
e presence of septa complicate lateral wall sinus graft
procedures, which leads to an increased likelihood of membrane
perforation.
Ostiomeatal Complex
e ostiomeatal unit is composed of the maxillary ostium, eth-
moid infundibulum, anterior ethmoid cells, hiatus semilunaris,
and the frontal recess, which encompasses the area of the middle
meatus.iscommonchannelallowsforairowandmucociliary
drainage of the frontal, maxillary, and anterior ethmoid sinuses.
Blockage in this area leads to impaired drainage of the maxil-
lary, frontal, and ethmoid sinuses, which may result in rhinosi-
nusitis and postoperative complications after implant or grafting
procedures.
Radiographic identication of the ostiomeatal complex and
related structures must be evaluated to prevent potential postopera-
tivecomplications.Pathologyorvariationswithintheostiomeatal
complex may lead to postoperative sinus graft morbidity or implant
complicationscausedbycompromisedmucociliarydrainage(alter-
ationofnormalsinusphysiology)ofthemaxillarysinus.
Blood Supply and Sensory Innervation
e vascular supply in the maxillary sinus is a vital part of the
healing and regeneration of bone after a sinus graft and healing
of a dental implant. e blood supply to the maxillary sinus is
derived from the maxillary artery, which emanates from the exter-
nal carotid artery. e maxillary artery supplies the bone sur-
rounding the sinus cavity and also the sinus membrane. Branches
of the maxillary artery, which most often include the posterior
superior alveolar artery and infraorbital artery, form endosseous
and extraosseous anastomoses that encompass the maxillary sinus.
e formation of the endosseous and extraosseous anastomoses in
the maxillary sinus is termed the double arterial arcade. Studies
haveshownvascularizationofpostgraftmaterialtodependonthe
intraosseous and extraosseous anastomoses, along with the blood
vessels of the Schneiderian membrane, which is supplied by the
posterior superior alveolar artery and the infraorbital artery along
the lateral wall.
16
ereexistdierentfactorsthatalterthevascularizationinthis
area.Withincreasingage,thenumberand sizeofbloodvessels
inthemaxilladecrease.Asboneresorptionincreases,thecortical
bonebecomesthin,resultinginlessvascularization.Asthelateral
wall becomes thinner, the blood supply to the lateral wall and lat-
eral aspect of the bone graft comes primarily from the periosteum,
resultinginacompromisedvascularizationtotheregion.

993
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
Extraosseous Anastomosis
eextraosseousanastomosisisfoundinapproximately44%of
the population and is usually in close approximation to the peri-
osteum of the lateral wall.
e extraosseous anastomosis is superior to the endosseous
unit,whichisapproximately15to20mmfromthedentatealveo-
larcrest.Tominimizevasculartraumatotheextraosseousanasto-
mosis, surgical and anatomic considerations should be addressed.
Ideally,verticalincisionsshould bemadeasshortaspossibleto
decreasethepossibilityofbloodvesseldamage.Itiscrucialtogain
adequate access to the lateral aspect of the maxilla, and the perios-
teumshouldbereectedfullthicknesswithgreatcare.Haphazard
reectionmayleadtoseveringordamagetotheanastomosis,with
resultant postoperative edema. Severing of the extraosseous anas-
tomosis may result in signicant increased bleeding during the
surgical procedure. is intraoperative complication may give rise
to impaired visibility for the clinician, along with increased sur-
geryduration.Additionally,postoperativecomplicationssuchas
pain, edema, and ecchymosis may result from the severing of these
bloodvessels.Iftraumatothesevesselsoccurs,directpressureor
the use of electrocautery may be used. However, electrocautery may
potentiallycausemembranedamageornecrosis.Ifseverebleed-
ing occurs, curved Kelly hemostats are used to clamp the bleeding
vessel,followedbyligatureplacement.Aslowlyresorbablesuture
withhightensilestrengthsuchasVicrylisrecommended.
Intraosseous Anastomosis
e intraosseous anastomosis is found within the lateral wall of the
sinus,whichsuppliesthelateralwallandthesinusmembrane.In
an edentulous maxilla with posterior vertical bone loss, the endos-
seousanastomosismaybe5to10mmfromtheedentulousridge.
eendosseousarteryhasbeenshowntobeobservedonCBCT
scans in approximately one-half of the patients requiring a sinus
graft.
17
However, anatomic cadaver studies have shown the preva-
lencetobe100%.
17
In82%ofcases,themostcommonanatomic
location was observed between the canine and second premolar
region.
18
However, with a long-term edentulous patient with a thin
lateral wall, the artery may be atrophied and almost nonexistent.
Surgical, radiographic, and anatomic considerations should be
addressedtominimizetraumatothesebloodvessels.eCBCT
radiographic identication is extremely important in identifying
these blood vessels before surgery so preparation may be made.
Radiographically,smalleranastomoseswillnotbeseenifthepixel
size(1.0mm)islessthanone-halfthesizeoftheanastomosis
vessel.Studieshaveshownthattheuseofa0.3or0.4CBCTpixel
sizeforradiographicevaluationwillmostlikelyshowthesmaller
anastomoses.
19
Studies have shown that in 20% of lateral wall osteoto-
mies signicant bleeding complications may occur,
20
mainly
becausetheanastomosisisgreaterthan1.0mmindiameter.
Ithasbeen shownthatvessels larger than1.0mmare more
problematic and associated with signicant bleeding, whereas
smallervessels(<1.0mm)areusuallyinsignicantandeasily
managed(Fig. 37.7;Box37.1).
Inmost cases, bleeding is a minor complication and of short
duration; however, in some instances it may be signicant and
dicultto manage.To controlbleeding, therearemany possible
treatments:(1)thepatientshouldberepositionedintoanupright
A
C
Infraorbital
artery
Maxillar
y artery
Posterior
superior artery
Intraosseous
branch of PSA
D
B
Fig. . Blood supply of the maxillary sinus. (A) Extraosseous and intraosseous anastomosis, which
is made up of the infraorbital and posterior superior artery. (B) Cross-sectional cone beam computerized
tomography image depicting intraosseous anastomosis (arrow). (C) Intraosseous notch (arrow) containing
the intraosseous anastomosis, which comprises the posterior superior artery and infraorbital artery. (D) Pos-
terior lateral nasal artery location in the medial wall of the maxillary sinus. PSA, Posterior Superior Artery.

994
PART VII Soft and Hard Tissue Rehabilitation
positionandpressureappliedwithasurgicalgauze;(2)electrocau-
tery may be used, although this may lead to membrane necrosis and
perforation,withpossiblemigrationofgraftmaterial;(3)asecond
window may be made proximal to the bleeding source to gain access
to the bleeding vessel, especially if location cannot be obtained from
the original window;and(4) cutting the bone and vessel with a
high-speeddiamondwithnoirrigation(whichcauterizesthevessel).
Posterior Lateral Nasal Artery
A posterior lateral nasal artery (branch of the sphenopalatine
arterythatalsorisesfromthemaxillaryartery)suppliesthemedial
aspect of the sinus cavity. e medial and posterior walls of the
maxillary sinus mucosa receive their blood supply from the poste-
rior lateral nasal artery.
During sinus graft surgery the clinician may be in close
approximation to this artery when elevating the membrane o the
medialwall.Careshouldbeexercisedtominimizetraumatothis
areabecauseaggressivereectionofthemembranemayresultin
trauma to the blood vessel or perforation into the nasal cavity.
Trauma to this artery may cause signicant bleeding in the
sinus proper and also within the nasal cavity. Because the medial
sinuswallisverythin(usuallyone-halfthethicknessofthelateral
wall),aggressivemembranereectionmayresultintrauma,lead-
ing to bleeding issues.
Sphenopalatine/Infraorbital Arteries
e sphenopalatine artery is also a branch of the maxillary artery and
enters the nasal cavity through the sphenopalatine foramen, which is
near the posterior portion of the superior meatus of the nose.
Asthesphenopalatinearteryexitstheforamen,itbranchesinto
the posterior lateral nasal artery and the posterior septal artery.
21
Additionally,theinfraorbitalarteryentersthemaxillarysinusviathe
infraorbital ssure in the roof of the sinus and ascends cranially into
the orbital cavity. Because of the anatomic locations of these blood
vessels, it is rarely a concern with respect to sinus graft surgery.
e sphenopalatine and infraorbital blood vessels are usually
not problematic for bleeding complications during lateral-approach
sinus elevation surgery because of their anatomic locations. How-
ever, incorrect incision locations and aggressive reection may
damagethebloodvessels.Ifbleedingdoesoccur,itisusuallyeasily
controlled with pressure and local hemostatic agents.
Maxillary Sinus Mucosa
e epithelial lining of the maxillary sinus is a continuation of the
nasal mucosa and is classied as a pseudostratied, ciliated colum-
nar epithelium, which is also called the respiratory epithelium.
e epithelial lining of the maxillary sinus is much thinner
and contains fewer blood vessels than the nasal epithelium. is
accountsforthemembranespalecolorandbluishhue.Fivepri-
marycelltypesexistinthistissue:(1)ciliatedcolumnarepithelial
cells,(2)nonciliatedcolumnarcells,(3)basalcells,(4)gobletcells,
and (5) seromucinous cells. e ciliated cells contain approxi-
mately50to200ciliapercell.Inahealthymaxillarysinusthe
cilia cells assist in clearing mucus from the sinus and into the naso-
pharynx. e nonciliated cells compose the apical aspect of the
membrane, contain microvilli, and serve to increase surface area.
ese cells have been theorized to facilitate humidication and
warmingofinspiredair.ebasalcell’sfunctionissimilartothat
of a stem cell that can dierentiate as needed. e goblet cells in
the maxillary sinus produce glycoproteins that are responsible for
the viscosity and elasticity of the mucus produced. e maxillary
sinus contains the highest concentration of goblet cells compared
with the other paranasal sinuses. e maxillary sinus membrane
alsoexhibitsfewelasticbersattachedtothebone(notenacious
attachmentisusuallypresent),whichsimplieselevationofthis
tissue from the bone during grafting procedures. e thickness
ofthesinusmucosainhealthvaries,butitisgenerally0.3to0.8
mm.
22
Insmokers,itvariesfromverythinandalmostnonexistent
to very thick, with a squamous type of epithelium.
Radiographically, normal, healthy paranasal sinuses reveal a
completely radiolucent (dark) maxillary sinus. Any radiopaque
(whitish)areawithinthesinuscavityisabnormal,andapatho-
logic condition should be suspected. e normal sinus membrane
isradiographicallyinvisible,whereasanyinammationorthick-
ening of this structure will be radiopaque. e density of the dis-
easedtissueoruidaccumulationwillbeproportionaltovarying
degrees of gray values.
Maintaining the integrity of the sinus membrane is crucial in
decreasing postoperative complications, including loss of graft
material and the possibility of infection.
Many factors may alter the physiology of the sinus mucosa,
such as viruses, bacteria, and foreign bodies (implants). Care
shouldbetakentominimizemembraneperforationsduringsur-
gery.Ifperforationsoccur,appropriaterepairtreatmentprotocols
should be followed.
Maxillary Sinus Mucociliary Clearance
Normal mucociliary ow is crucial to maintaining the healthy
physiologyofthe maxillary sinus.Inahealthysinusanadequate
system of mucus production, clearance, and drainage is maintained.
e key to normal sinus physiology is the proper function of the
cilia, which is the main component of the mucociliary transport
system. e cilia move contaminants toward the natural ostium and
then to the nasopharynx. e cilia of the columnar epithelium beat
towardtheostiumatapproximately15cyclesperminute,witha
sti stroke through the serous layer, reaching into the mucoid layer.
ey recover with a limp reverse stroke within the serous layer. is
mechanism slowly propels the mucoid layer toward the ostium at a
rateof9mmperminuteandintothemiddlemeatusofthenose.
22
Inhealth, mucoid uid is transported towardtheostium of
the maxillary sinus and drains into the nasal cavity, eliminating
inhaled small particles and microorganisms. is mucociliary
transport system is an active transport system that relies heavily
on oxygen. e amount of oxygen absorbed from the blood is not
adequatetomaintainthisdrainagesystem;additionaloxygenhas
to be absorbed from the air in the sinus. is is why the patency of
the ostium is crucial in maintaining the normal transport system.
• Endosseousanastomosis(withinthelateralwallofsinus)
-supplieslateralwallandsinusmembrane
1. Posteriorsuperioralveolarartery
2. Infraorbitalartery
• Extraosseousanastomosis(withinperiosteum)
-suppliessinusmucousmembranes
1. Posteriorsuperioralveolarartery
2. Infraorbitalartery
• Posteriorlateralnasalartery(medialandposteriorwall)
-suppliesmedialandposteriorwallsofmaxillarysinus
BOX
37.1
Arterial Supply to Posterior Maxilla
(Double Arterial Arcade)

995
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
Variouselementsmaydecreasethe numberofcilia andslow
theirbeatingeciency.Viralinfections,pollution, allergicreac-
tions, and certain medications may aect the cilia in this way.
Genetic disorders (e.g., dyskinetic cilia syndrome) and factors
such as long-standing dehydration, anticholinergic medications
and antihistamines, cigarette smoke, and chemical toxins also can
aect ciliary action
23
(Fig.37.8).
An alteration in the sinus ostium patency or the quality
of secretions can lead to disruption in ciliary action, which
may result in rhinosinusitis. For clearance to be maintained,
adequateventilationisnecessary.Ventilationanddrainageare
dependent on the ostiomeatal unit, which is the main sinus
opening.Ciliarymovementsofciliatedepithelialcellsdictate
clearance of the maxillarysinus. Itis important to maintain
the patency of the maxillary ostium and the ostiomeatal com-
plexinthepostoperativeperiodtominimizethepossibilityof
complications.
e physiologic mucociliary transport system may be com-
promised by abnormalities in the cilia, which include a decrease
in overall ciliary number and poor coordination of their move-
ment. is altered physiology may result in an increased mor-
bidity of implant placement or bone graft healing. erefore it
is crucial that the mucociliary drainage mechanism be main-
tained throughout the postoperative treatment period. is
is most likely accomplished with good surgical technique,
evaluation and treatment of prior drainage issues, and strict
adherencetotheuseofpharmacologicagents(e.g.,antibiotics,
corticosteroids).
Organisms trapped on mucus Mucus movement
Ostium
Outer layer
of mucus
Periciliary
serous fluid
Pseudostratified
columnar
epithelial cell
Mucous gland
Cilia
Goblet cell
Basal cell
Air
Gel phase
Propulsion
Aqueous phase
Recovery
Epithelium
A
B
C
D
Fig. . Maxillary sinus membrane (Schneiderian Membrane). (A) The pseudostratified columnar epi-
thelium cells have 50 to 200 cilia per cell that beat toward the ostium to help clear 1 L of mucus from
goblet and mucous glands each day from the sinus. In health, the mucous has two layers: a bottom serous
layer and top mucoid layer. The cilia beat with a stiff stroke in the mucoid layer toward the ostium and a
relaxed recovery stroke within the serous layer. (B) Cross-sectional image depicting an inflamed Schnei-
derian membrane. If the sinus membrane is of normal thickness, it will not be visible on a radiograph. (C)
Clinical image depicting the thinness of the lateral wall and show through (dark blue) of the Schneiderian
membrane. (D) Bluish hue of the membrane after lateral wall window preparation.

996
PART VII Soft and Hard Tissue Rehabilitation
Maxillary Sinus Bacterial Flora
ereismuchdebateonthebacterialoraofthemaxillarysinus.
Maxillary sinuses have been considered to be generally sterile in
health;however, bacteria can colonizewithin the sinus without
producingsymptoms.Intheory,themechanismbywhichaster-
ile environment is maintained includes the mucociliary clearance
system, immune system, and the production of nitric oxide within
thesinuscavity.Inrecentendoscopicstudies,normalsinuseswere
showntobenonsterile,with62.3%exhibitingbacterialcoloniza-
tion. e most common bacteria cultured were Streptococcus viri-
dans, Staphylococcus epidermidis, and S. pneumoniae.
24
e culture
ndings for secretions in acute maxillary sinusitis yielded high
numbers of leukocytes, S. pneumoniae, or S. pyogenes, with Hae-
mophilus inuenzae being recovered from the purulent exudates
with lower numbers of staphylococci. Other reports have indicated
thebacterialoraofthemaxillarysinusconsistsofnonhemolytic
and alpha hemolytic streptococci, as well as Neisseriaspp.Addi-
tional microorganisms identiable in various quantities belong to
staphylococci, Haemophilus spp., pneumococci, Mycoplasma spp.,
and Bacteroides spp. is is important to note because the sinus
graft procedure often violates the sinus mucosa, and bacteria may
contaminate the graft site, leading to postoperative complications.
e implant clinician must understand the importance of reduc-
ing the bacterial count and possible microorganisms that may initiate
infectionsinthemaxillarysinus.Astrictaseptictechniqueshouldbe
adhered to during any surgical procedures that invade the maxillary
sinusproper.iswillminimizethepossibilityofbacterialcoloniza-
tion within the graft, which may lead to increased morbidity. e
type of bacteria inhabiting the sinus is very important because it
dictates what antibiotic is prescribed preoperatively, postoperatively,
and therapeutically in case of infection. e most common bacteria
present in the sinus must be susceptible to the specic antibiotic to
prevent infection and decrease the morbidity of the graft. e antibi-
oticselectedshouldnotbetheclinicians“favorite”;insteaditshould
be the most ideal antibiotic, which is specic for the involved bac-
teria.Ideally,Augmentin(875/125mg)hasbeenshowntobemost
eective antibiotic for bacterial infections in the maxillary sinus.
Maxillary Sinus: Clinical Assessment
To establish adequate osseous morphology for the placement of
endosteal implants in the resorbed maxillary posterior region,
various grafting techniques have been developed to increase bone
volume.In1987Misch
25
developed four dierent categories for
thetreatmentoftheposteriormaxilla(termedsubantral[SA])as
SA-1throughSA-4andwaslatermodiedandupdatedbyResnik
in2017(Fig.37.9). eSA-1posteriormaxilla allowsimplant
placement inferior to the sinus cavity, without penetration into
Fig. . Subantral augmentation classification. (A) SA-1: implant placement that does not extend into
the maxillary sinus proper. (B) SA-2: implant placement that elevates the sinus membrane approximately
1 to 2 mm without bone grafting. (C) SA-3: implant placement and simultaneous bone grafting by either a
crestal or lateral-wall approach. (D) SA-4: lateral wall sinus augmentation with delayed implant placement.

997
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
thesinusproper.Becausethesinusoorisnotaltered,apreexist-
ing sinus pathology or anatomic variant will be less likely to aect
thehealingprocess.Assuch,ifthepatienthasapreexistingmaxil-
lary sinus condition or develops a sinus infection after implant
placement, then implants are not at risk of becoming contami-
nated.However,theSA-2toSA-4surgicalproceduresdoalterthe
sinusmembrane andsinus oor.Withthesetreatmentoptions,
a thorough preoperative evaluation is completed to rule out any
existingpathologicconditioninthemaxillarysinus.Inthisway,
the risk of possible mucus or bacteria contaminating the graft and
creating a bacterial smear layer on the implant is reduced. ere-
fore the possibility of impaired bone formation during healing is
reduced.Inaddition, becauseof theproximityofthe maxillary
sinus to numerous vital structures, postoperative complications
can be very severe and even life-threatening.
Pathologicconditionsassociatedwiththeparanasalsinusesare
commonailmentsandaictmorethan31millionpeopleeach
year.Approximately16millionpeoplewillseekmedicalassistance
related to sinusitis; yet sinusitis is one of the most commonly
overlookeddiseasesinclinicalpractice.Potentialinfectioninthe
regionofthesinusesmayresultinseverecomplications.Infections
in this area have been reported to result in sinusitis, orbital celluli-
tis,meningitis,osteomyelitis,andcavernoussinusthrombosis.In
fact,paranasalsinusinfectionaccountsforapproximately5%to
10%ofallbrainabscessesreportedeachyear.
26
A physical examination of the maxillary sinus evaluates the
middle third of the face for the presence of asymmetry, deformity,
swelling, erythema, ecchymosis, hematoma, or facial tenderness
(Table37.1).Nasalcongestionorobstruction,prevalentnasaldis-
charge,epistaxis(bleedingfromthenose),anosmia(thelossofthe
senseofsmell),and/orhalitosis(badbreath)arenoted.
e clinical examination for maxillary rhinosinusitis concerns the
regions surrounding the maxillary antrum. e examination is con-
ducted to assess each wall surrounding the maxillary sinus separately.
e infraorbital foramen on the facial wall of the antrum is palpated
through the soft tissue of the cheeks or intraorally to determine whether
tenderness or discomfort is present. e intraoral examination assesses
theooroftheantrumbyalveolarulceration,expansion,tenderness,
paresthesia, and oroantral stulae. e eyes are examined to evaluate
the superior wall of the sinus for proptosis, pupillary level, lack of eye
movement,anddiplopia.enasaluidsmaybeusedtoevaluatethe
medial wall of the sinus by asking the patient to blow the nose in a
waxedpaper.emucusshouldbeclearandthininnature.Ayellow
or greenishtintor thickened discharge indicates infection. Infected
maxillary sinuses typically are symptomatic, which can exhibit exudate
in the middle meatus and may be inspected with a nasal speculum
andheadlight(rhinoscopy)throughthenares.emethodsofexami-
nation of the infected maxillary sinus may include transillumination,
nasoendoscopy, bacteriology, cytology, beroptic antroscopy, and radi-
ographyCBCT,ormagneticresonanceimaging[MRI]).
Maxillary Sinus Radiographic Evaluation
Variousradiographictechniqueshavebeenusedinimplantdentistry
toevaluatethemaxillaryposteriorregion.Intheearlydaysoforal
implantology, evaluation of this area was limited to 2-dimensional
(2D)radiographs.However,thesetypesofradiographshaveinher-
ent disadvantages that are aected by magnication and distortion,
whichleadstoerrorsindiagnosisandtreatmentplanning.Currently,
thisanatomicareaisevaluatedmainlybytheuseof3Dradiographic
techniques(CBCT)ormedicalCTbecausetheyhavebecomemore
accurateandecient,withasignicantreducedradiation.
Cone Beam Computerized Tomography
CBCT surveyshave allowedthe implant clinician to evaluate
anatomic structures, anatomic variants, and pathologies more
accurately. Many software programs are available that allow
combining 3D images with computer software and allow an
accurateassessmentofthemaxillarysinus.Becausevisualization
of the maxillary sinus and surrounding structures are crucial for
the proper diagnosis and treatment planning, it is highly sug-
gestedtheimplantclinicianutilizeCBCTanytimeprocedures
involve the maxillary sinus.
Presently,noradiographicmodalityprovidesmoreinformation
abouttheparanasalsinusesthanCBCT.istypeofradiography
provides much more detailed information about the anatomy and
pathologic condition of the sinuses compared with 2D radiog-
raphy.StudieshaveconcludedthatCBCTisthebestoptionfor
viewing the surrounding osseous structures and pathologic condi-
tion in the maxillary sinuses.
27,28
e maxillary sinus can be evaluated with most CBCT images,
including reformatted axial, panoramic, cross-sectional, sagittal, and
3Dimages.Mostphysiciansusethecoronalradiographstoevaluatethe
paranasal sinuses. e implant clinician must have a clear understand-
ingoftheCBCTradiographicanatomyandthepathologicconditions
associated with the posterior maxilla and maxillary sinus regions.
Normal Anatomy
Maxillary Sinus Membrane (Schneiderian
Membrane)
ACBCTscanofnormal,healthyparanasalsinusesrevealsacom-
pletelyradiolucent(dark)maxillarysinus.Anyradiopaque(whit-
ish) area within the sinus cavity is abnormal, and a pathologic
condition should be suspected. e normal sinus membrane is
radiographicallyinvisible,whereasanyinammationorthicken-
ing of this structure will be radiopaque. e density of the dis-
easedtissueoruidaccumulationwillbeproportionaltovarying
degrees of gray values.
Preoperative and Postoperative Physical
Examination
Site Signs of Infection
Inferior wall Bulgeinhardpalate,ill-ttingden-
ture,looseteeth,hypesthesiaor
nonvitalteeth,bleeding,palatal
erosion,oroantralstula
Medial wall Nasalobstruction,nasaldischarge,
epistaxis,cacosmia,visiblemass
innostril
Anterior wall Swelling,pain,skinchanges
Posterior wall Midfacepain,hypesthesiaofone-
halfofface,lossoffunctionof
lowercranialnerves
Superior wall Diplopia(doublevision),proptosis
(eyebulgingout),chemosis,pain
orhypesthesia,decreasedvisual
acuity
TABLE
37.1

998
PART VII Soft and Hard Tissue Rehabilitation
Ostiomeatal Complex
e ostiomeatal unit is composed of the maxillary ostium, eth-
moid infundibulum, anterior ethmoid cells, and the frontal recess.
e main drainage avenue of the maxillary sinus is through the
ostium. e maxillary ostium is bounded superiorly by the eth-
moid sinuses and inferiorly by the uncinate process. e uncinate
process is a bony knifelike projection that is attached inferiorly to
theinferiorturbinateandposteriorlyhasafreemargin.Drainage
continues through the ostium into the infundibulum, which is a
narrow passageway leading into the middle meatus. e middle
meatus is the radiolucent space bounded by the middle and infe-
rior turbinates.
Nasal Cavity
Withinthenasalcavity,threenasalturbinatesorconchae(supe-
rior,middle,andinferior)existandaresmalldownwardprojec-
tions of bone. Between the turbinates is a space or recess termed
a meatus. e respiratory epithelium covers the turbinates and
meatus and warms, moistens, and cleans the air that is respirated
into the lungs.
e nasal septum is the bony partition that creates a barrier
between the right and left sides of the nasal cavity. Obstructions
within any aspect of the nasal system predispose the area to patho-
logicconditions(Fig.37.10).
Maxillary Sinus: Anatomical Variants
Numerous anatomic variants arise that can predispose a patient
topostsurgicalcomplications.Whentheseconditionsarenoted,
apharmacologicprotocolmayneedtobealteredand/orimplants
may be placed after the sinus graft has matured, rather than pre-
disposing them to an increased risk by inserting them at the same
timeasthesinusgraft.Asstatedpreviously,patencyoftheostium
isparamounttomaintaindrainage.Preexistingskeletalandbony
abnormalities of the ostiomeatal complex may compromise the
patency of the maxillary ostium, thereby, predisposing patients to
maxillary rhinosinusitis.
Paradoxical middle turbinate
Deflected
ucinate
process
Polyps
Non-patent
ostium
Mucous
retention cyst
Big nose
variant
Deviated
septum
Concha
bullosa
Hiatus
Semilunaris
Infundibulum
Osteomeatal
complex
Uncinate
process
Middle
meatus
Maxillar
y
sinus
Ostium
Maxillary
sinus
Middle turbinate Inferior meatusInferior turbinate Nasal septum
Eye
Ethmoid
sinus
Ethmoid
bulla
Frontal
sinus
A
B
Fig. . (A) Normal paranasal anatomy. (B) Paranasal pathology and anatomic variants.

999
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
Nasal Septum Deviation
Anasalseptumdeviationisaverycommonanatomicvariant,occur-
ringinasmuchas70%ofthepopulationolderthan14years.is
bony variant in extremes may cause obstruction of the ostiomeatal
unit, which resultsininammationfromairturbulence,causing
increasedmucosaldryingandparticledeposition.Ifthedeviation
is long-standing, then atrophy of the middle turbinate may occur,
resultinginnarrowingoftheostiomeatalcomplex(Fig.37.11).
29
Timmenga and colleagues
30
evaluated45patientswhoreceived
85sinusgraftswithendoscopypostsurgery. Ofthe45patients,
ve were found to have sinusitis postsurgery; all ve of those
patients had a nasal deviation or oversized turbinate. erefore
when these conditions are observed, consideration should be given
to not place the implant at the same time as the sinus graft, and
the recommended preoperative and postoperative pharmacologic
protocol is especially warranted.
Middle Turbinate Variants
e middle turbinate plays a signicant role in proper drainage of
themaxillarysinus.Aconchabullosaisapneumatizationwithin
the middle turbinate and may occlude the ostiomeatal complex,
compromising adequate drainage. is variant is seen in approxi-
mately4%to15%ofthepopulation(Fig.37.12).
31
Anothervari-
ant in this anatomic structure is a paradoxically curved middle
turbinate, which presents a concavity toward the septum, decreas-
ingthesizeofthemeatus.isalsopredisposesthepatienttoa
higher incidence of sinus disease.
Uncinate Process Variants
e uncinate process is a projection of the ethmoid bone which is
located in the wall of the lateral nasal cavity. is bony process is an
importantanatomicstructureinthepatencyoftheostium.Adeected
uncinateprocess(eitherlaterallyormedially)cannarrowtheethmoid
infundibulum, aecting the ostiomeatal complex. Perforations may
also be present within the uncinate process, leading to communication
betweenthenasalcavityandethmoidinfundibulum.Inaddition,the
uncinateprocessmaybepneumatized.Althoughthisisrare,itmay
compromise adequate clearance and drainage of the maxillary sinus.
Supplemental Ostia
Asupplementalostiumorsecondaryostiamayoccurbetweenthe
maxillary sinus and the middle meatus, which is often found in
theposteriorfontanelles(PF).ismaybefoundinapproximately
18%to30%ofindividuals.Becausethesesecondaryopeningsare
usually located posterior and inferior to the natural ostium, they
may predispose the patient to sinusitis by the recirculation of
infected secretions from the primary meatus back into the sinus cav-
ity. On occasion, these secondary ostia may be encountered during
the elevation of the medial wall of the antrum before placement of
thesinusgraft.Whenobserved,apieceofcollagenisplacedoverthe
site to prevent graft material from entering the nasal cavity.
Maxillary Hypoplasia
Hypoplasia of the maxillary sinus may be a direct result from
trauma, infection, surgical intervention, or irradiation to the max-
illa during the development of the maxillary bone. ese condi-
tions interrupt the maxillary growth center, producing a smaller
than normal maxilla. A malformed and positioned uncinate
process is associated with this disorder, leading to chronic sinus
drainage problems. Most often, these patients have adequate bone
Fig. . Nasal septum deviation is a common variant. Extreme cases
may obstruct the ostiomeatal unit and increase the risk of sinusitis after a
sinus graft.
MT
IT
A
B
Fig. . (A) Nasal cavity anatomy: inferior turbinate (IT), middle turbi-
nate (MT), inferior meatus (red arrow), middle meatus (yellow arrow). Note
the paradoxical middle turbinate. (B) Coronal image depicting concha bul-
losa (arrow) and deviated septum.

1000
PART VII Soft and Hard Tissue Rehabilitation
height for endosteal implant placement, and a sinus graft is not
requiredtogainverticalheight(Fig.37.13)
Inferior Turbinate and Meatus Pneumatization
(Big-Nose Variant)
Misch had observed, on rare occasion, that the inferior third of
the nasal cavity pneumatizes within the maxilla and resides over
the alveolar residual ridge. An evaluation of 550 computerized
tomography(CT)scansofcompleteorpartiallyedentulousmaxil-
laefoundthisconditionin18patients(3%incidence).Whenthe
patient has this condition, the maxillary sinus is lateral to the eden-
tulousridge.When inadequateboneheight ispresentbelowthis
structure, a sinus graft does not increase available bone height for an
implant.isconditionisdiculttoobserveonatwo-dimensional
panoramicradiograph.Ifunaware,thentheimplantcanbeplaced
into the nasal cavity above the residual ridge and even penetrate the
inferiorturbinate.Asinusgraftiscontraindicatedwiththispatient
condition because the sinus is lateral to the position of the implants.
Instead,inmostcasesanonlaygraftisrequiredtoincreasebone
height(Fig.37.14).
Maxillary Sinus Pathology
Apre-existing,pathologic,maxillarysinusconditionmaybearela-
tive or absolute contraindication for many procedures that will alter
thesinusoorbeforeorinconjunctionwithsinusgraftingand/or
implant insertion. e risk of postoperative infection is elevated and
may compromise the health of the implant and the patient. ere-
fore pathologic conditions, either preoperative or postoperative, of a
maxillary sinus should be evaluated, diagnosed, and treated.
Pathologic conditions of the maxillary sinus may be divided
into four categories: (1) inammatory lesions, (2) cystic lesions,
(3)neoplasms,and(4)antrolithsandforeignbodies.Studieshave
shownthat20%to45%oftheasymptomaticpopulationhasasub-
clinical pathologic condition in the maxillary sinus. e author has
evaluatedapproximately2000prospectivecandidatesformaxillary
sinusaugmentationproceduresattheMischInternationalImplant
Institute for signs of pathology. e results concluded 38.7% of
asymptomatic patients had maxillary sinus pathologic conditions
on CBCT scan evaluation. Manji and colleagues evaluated 275
patients and concluded that 45.1% were classied as exhibiting
sinus pathology (i.e., 56.5% had mucosal thickening (5 mm),
28.2%withpolypoidalthickening,8.9%partialopacicationand/
orair/uidlevel,and6.5%completeopacication).
32
Because of
this increased incidence, it is highly recommended that a thorough
radiographic evaluation be completed on all prospective sinus eleva-
tion patients.
Inflammatory Disease
Inammatory conditions can aect the maxillary sinus from
odontogenic and nonodontogenic causes.
Odontogenic Rhinosinusitis (Periapical Mucositis)
Odontogenic sinusitis describes a type of sinus disease in which
radiographic,microbiologic,and/orclinicalevidenceindicatesitisof
adentalorigin(i.e.,fromatooth).ecloseproximityoftheroots
ofthemaxillaryposteriorteethtotheoorofthesinussuggestany
inammatorychangesintheperiodontiumorsurroundingalveolar
bone may result in pathologic conditions in the maxillary sinus.
Etiology. Odontogenic sinusitis is usually the result of an
infectedtooth(e.g.,periapicalabscess,cyst,granuloma,periodontal
disease)thatcausesanexpansilelesionwithintheoorofthesinus.
Periapicalinammation has beenshownto becapableofaect-
ing the sinus mucosa, with and without perforation of the cortical
boneofthesinusoor.Infectionandinammatorymediatorsare
capable of spreading directly or via bone marrow, blood vessels,
and lymphatics to the maxillary sinus, causing an inammatory
response.
33
Additionaletiologicfactorsincludesinusperforations
duringextractionsandforeignbodies(e.g.,gutta-percha,roottips,
amalgam).Odontogenicrhinosinusitisisoftenpolymicrobial,with
anaerobic streptococci, Bacteroides spp., Proteus spp., and coliform
bacilliinvolved.Studieshaveshown10%to40%ofallrhinosinus-
itis sinusitis cases may have an underlying dental pathology.
34,35
Radiographic Appearance. e radiographic evaluation of
patients with odontogenic sinusitis will most commonly dem-
onstrate a unilateral maxillary sinusitis. A unilateral maxillary
odontogenicsinusitisisoftenoverlookedonCBCTscansbecause
theyarefrequently asymptomatic. Involvementof the ostiome-
atal complex may result in extension to adjacent paranasal sinuses
(e.g., ethmoid, frontal, sphenoid), ranging from 27% to 60%
among patients with odontogenic sinusitis.
36
Odontogenic sinus-
itishas been shownto exhibit bilateralinvolvementin 20% of
Fig. . Inferior meatus pneumatization (big nose variant). Cone beam
computerized tomographic panoramic image depicting the abnormally
large nasal cavity extending into the molar area.
Fig. . Maxillary hypoplasia. Coronal cone beam computerized
tomographic view of an abnormally small sized maxillary sinus

1001
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
patients.Insomecases,aslightthickeningofthesinusmembrane
may be present adjacent to the oending tooth.
37
Usually the
radiographic appearance will be a radiopaque band that follows
thecontoursofthesinusoor.
Dierential Diagnosis. Odontogenic sinusitis may be confused
withacuterhinosinusitissinusitis;however,acuterhinosinusitisis
almost always symptomatic. Mild mucosal thickening from a non-
odontogenicorigin(e.g.,smoking,allergy)mayalsoshowsimilar
radiographic signs. However, the nonodontogenic origin may be
conrmed from lack of radiographic evidence of a diseased or pain-
ful tooth.
Treatment. Before any type of sinus augmentation or implant
placement into the sinus, the tooth or teeth involved should be
treatedperiodontally,endodontically,orextracted.Afterintraoral
softtissuehealingandresolutionofthepathologiccondition(i.e.,
aminimumof6weeks),thebonegraftand/orimplantmaybe
performed with minimal morbidity. e removal of unhealthy
teeth decreases sinus membrane thickening, but most of the time
itdoesnotcompletelyresolveit.Inaddition,epithelialmetaplasia
with the ciliated mucosa changing to simple cuboidal and strati-
edsquamouskeratinizedtissuemayresult.erefore,depend-
ing on the severity, in some cases the mucosal thickness may
remain because of the change in epithelia structure and metaplasia
changes
6
(Fig.37.15).
Mild Mucosal Thickening (Nonodontogenic)
Sinus membrane thickening has been shown to be present in
approximately46.7%ofpatients,withequaldistributionbetween
healthy and unhealthy natural teeth.
38
e most common area for
the mucosal thickening has been shown to be in the midsagittal
sinusregion,whichisadjacenttotherstandsecondmolars.In
the literature, it is accepted that mucosal thickening greater than 2
mm is considered a pathologic sinus membrane.
39-42
Etiology. Local odontogenic issues, such as periapical pathol-
ogy, periodontal disease, and the health of the adjacent dentition,
havebeenshowntobetheetiologicfactorintheinammatory
responsetothesinusmembraneinapproximately50%ofcases.
43
However, nonodontogenic factors such as smoking,
44
allergies,
sinus congestion, mold, and air pollution may aggravate the sinus
mucosa,resultinginmildthickening.Chronicinammatorycon-
ditionsmayresultinalteredbacterialora,alongwithmucociliary
clearance and cilia changes.
Radiographic Appearance. OnaCBCTimage,usuallythick-
ened mucosa will appear as a radiopaque widened membrane.
ickened mucosa can easily be seen when evaluating axial images.
Treatment. Usually no treatment is necessary because mild
mucosal thickening is asymptomatic. Studies have shown that
slight mucosal thickening allows for sinus grafting procedures to
be completed with a decreased incidence of membrane perfora-
tion(Fig.37.16).
Acute Rhinosinusitis
Anonodontogenicpathologicconditionmayalsoresultininam-
mation in the form of sinusitis. e most common type of sinus-
itis is acute rhinosinusitis (i.e., sinusitis symptoms of less than
3months).e signs and symptomsofacuterhinosinusitis are
rather nonspecic, making it dicult to dierentiate from the
commoncold,inuenzatypeofsymptoms,andallergicrhinitis.
However, the most common symptoms include purulent nasal
discharge, facial pain and tenderness, nasal congestion, and pos-
sible fever.
Acute maxillary rhinosinusitis results in 22 to 25 million
patient visits to a physician in the United States each year, with
a direct or indirect cost of $6 billion. Although four paranasal
sinuses exist in the skull, the most common involved in rhinosi-
nusitis are the maxillary and frontal sinuses.
45
Etiology. An inammatory process that extends from the
nasal cavity after a viral upper respiratory infection often causes
acute maxillary sinusitis. Microbiological cultures have shown the
most common pathogens causing acute rhinosinusitis are S. pneu-
moniae, H. inuenzae, and Moraxella catarrhalis. ese pathogens
includeapproximately20%to27%β-lactamase–resistantbacte-
ria. S. aureus has also been cited, with the microbiology of acute
rhinosinusitis. However, this pathogen is usually only seen in nos-
ocomial(hospital-induced)sinusitisandisunlikelytobeseenin
an elective sinus graft patient.
e most important factor in the pathogenesis of acute rhinosi-
nusitis is the patency of the maxillary ostium.
46,47
Local predispos-
ingcausesofsinusitisincludeinammationandedemaassociated
with a viral upper respiratory tract infection or allergic rhinitis.
As a consequence, mucous production within the sinus may
be abnormal in quality or quantity, along with a compromised
Fig. . Odontogenic rhinosinusitis. Cone beam computerized tomo-
graphic panoramic view showing molar roots extending into the maxillary
sinus, resulting in inflammation of the sinus membrane. Note the com-
munication between the maxillary molar roots and the maxillary sinuses.
Fig. . Mild mucosal thickening. Three-dimensional axial view show-
ing bilateral mucosal thickening (gray area surrounding the bony walls of
the maxillary sinus).

1002
PART VII Soft and Hard Tissue Rehabilitation
mucociliarytransport.Inanoccludedostium,anaccumulationof
inammatorycells,bacteria,andmucusexists.Phagocytosisofthe
bacteriaisimpairedwithimmunoglobulin(Ig)-dependentactivi-
ties decreased by the low concentration of IgA, IgG, and IgM
found in infected secretions.
e oxygen tension inside the maxillary sinus has signicant
eectsonpathologicconditions.Whentheoxygentensioninthe
sinus is altered, resultant sinusitis occurs. Growth of anaerobic and
facultative organisms proliferate in this environment.
48
Many fac-
torsmay alterthe normaloxygentensionwithin thesinuses.A
directcorrelationexistsbetweentheostiumsizeandtheoxygen
tensioninthesinus.Inpatientswithrecurrentepisodesofsinus-
itis, oxygen tension is often reduced, even when infection is not
present.Asaconsequence,ahistoryofrecurrentacuterhinosinus-
itis is relevant to determine whether a bone graft or dental implant
may be at increased risk of morbidity.
Radiographic Appearance. e radiographic hallmark in
acuterhinosinusitisistheappearanceofanair-uidlevel.Alineof
demarcationwillbepresentbetweentheuidandtheairwithin
themaxillarysinus.Ifthepatientisradiographically positioned
supine,thentheuidwillaccumulateintheposteriorarea;ifthe
patientisuprightduringtheimagingsurvey,theuidwillbeseen
on the oor and horizontal in nature. Additional radiographic
signs include smooth, thickened mucosa of the sinus, with pos-
sibleopacication.Inseverecases,thesinuscavitymayllcom-
pletely with supportive exudates, which gives the appearance of a
completelyopaciedsinus.Withthesecharacteristics,theterms
pyocele and empyema have been applied.
Treatment. Because acute rhinosinusitis is one of the most
common health problems today, patients having sinus grafting
procedures should be well screened for a past history and cur-
rentsymptoms.Eventhoughacuterhinosinusitisisaself-limiting
disease, a symptomatic patient should be treated and cleared by
their physician before any grafting procedures. ese patients are
alsomorepronetopostoperativerhinosinusitis.Asaresult,asinus
graft is performed and given a longer healing period before place-
mentofanimplant.Inaddition,thesuggestedantibioticcoverage
may be altered and extended, both before and after the sinus graft
procedure(Fig.37.17).
Chronic Rhinosinusitis
Chronicrhinosinusitisisatermusedforasinusitisthatdoesnot
resolvein3monthsandalsohasrecurrentepisodes.Itisthemost
common chronic disease in the United States, aecting approxi-
mately 37 million people. Symptoms of chronic rhinosinusitis
are associated with periodic episodes of purulent nasal discharge,
nasal congestion, and facial pain.
Etiology. Asmaxillaryrhinosinusitisprogressesfromtheacute
phase to the chronic phase, anaerobic bacteria become the predomi-
nant pathogens. e microbiology of chronic rhinosinusitis is very
dicultto determinebecause oftheinabilitytoacquireaccurate
cultures. Studies have shown that possible bacteria include Bacte-
roides spp., anaerobic gram-positive cocci, Fusobacterium spp., and
aerobicorganisms (Streptococcus spp., Haemophilus spp., Staphylo-
coccusspp.).
49
AMayoClinicstudyshowedthatin96%ofpatients
with chronic rhinosinusitis, active fungal growth was present.
50
Radiographic Appearance. Chronic rhinosinusitis may
appear radiographically as thickened sinus mucosa, complete
opacicationoftheantrum,and/orscleroticchangesinthesinus
walls(which givethe appearanceof densercorticalbonein the
lateralwalls).
Treatment. Medical evaluation and clearance by an experi-
encedphysicianinsinuspathology(e.g.,otolaryngologist[ENT])
is highly recommended for patients with chronic maxillary rhi-
nosinusitis before any sinus grafting, because signicant bacterial
resistance and fungal growth is highly probable. Fungal infections
areoftendiculttotreatandcontrol,andseriouscomplications
mayresultinpostoperativesinusgraftpatients.Inmanychronic
rhinosinusitis patients, a sterile and nonpathologic sinus is dif-
culttoobtain,contraindicating(absolute)sinusgraftingand/or
implants.
Allergic Rhinosinusitis
Etiology. Allergicsinusitisisalocalresponsewithinthemaxil-
lary sinus caused by an irritating allergen in the upper respiratory
tract. erefore allergens may be a cause of acute or chronic rhi-
nosinusitis. is category of sinusitis may be the most common
form, with 15% to 56% of patients undergoing endoscopy for
sinusitisshowingevidenceofallergy.Allergicrhinosinusitisoften
leadstochronicsinusitisin15%to60%ofpatients.
51
e sinus
mucosa frequently becomes irregular or lobulated, with resultant
polyp formation.
Radiographic Appearance. Polypformationrelatedtoallergic
sinusitis is usually characterized by multiple, smooth, rounded,
radiopaque shadows on the walls of the maxillary sinus. Most
commonly, polyps initially are located near the ostium and are
easilyobservedonaCBCTscan.Inadvancedcases,ostiumocclu-
sion, along with displacement or destruction of the sinus walls,
may be present with a radiographic image of a completely opaci-
ed sinus.
Treatment. Whenpatientshaveahistoryofallergicrhinosinus-
itis, special attention must be given to a patent ostium, bacterial
resistance,andclosepostoperativesupervision.Polyps,ifenlarged
or too numerous, may be required to be removed before the sinus
BA
Fig. . Acute rhinosinusitis. (A and B) Flat radiopaque (gray) line within the maxillary sinus, which is
termed an air-fluid level and consistent with acute rhinosinusitis.

1003
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
graft.ismaybeperformedthroughananteriorCaldwell-Luc
approach or by an endoscopic procedure via the maxillary ostium.
Allergicsinusitispatientsoftenhaveagreaterriskofcomplica-
tions related to an increase in allergen production. Because sinus
grafting is an elective procedure, the time of year for the surgery
may be altered to decrease the postoperative infection risk. For
example,ifhayfeveroragrassallergyisrelatedtothepatient’s
sinusitis, then the sinus graft surgery should be performed in the
season or seasons that have least risk to aggravate the sinus mucosa
(i.e.,winter orfall).Inseverecasesof polyposis,any procedure
violating the sinus proper may be an absolute contraindication
(Fig.37.18).
Fungal Rhinosinusitis (Eosinophilic Fungal Rhinosinusitis)
Granulomatousrhinosinusitis is a veryserious (and often over-
looked)disorderwithinthemaxillarysinus.Patientswhoexhibit
signs of fungal rhinosinusitis may indicate an extensive history of
antibiotic use, chronic exposure to mold or fungus in the envi-
ronment, or history of immunosuppression. Fungal rhinosinusitis
has been categorized into ve types: acute necrotizing (fulmi-
nant), chronic invasive, chronic granulomatous invasive, fungal
hall(sinusmycetoma),andallergic.erstthreetypesareclas-
sied as tissue-invasive and the last two are noninvasive fungal
rhinosinusitis.
52
Etiology. Fungal infections are usually caused by aspergillosis,
mucormycosis,orhistoplasmosis.Chronicrhinosinusitispatients
should always be evaluated for granulomatous conditions because
a high percentage of fungal growth exists in this patient popula-
tion. Of concern in these patients is eosinophils are activated that
releasemajorbasicprotein(MBP)intothemucus,whichattacks
and destroys the fungus. However, this may result in the mem-
brane being irritated and possibly irreversibly damaged, which
allows bacteria to proliferate. ree possible clinical signs may
dierentiate fungal rhinosinusitis from acute or chronic rhino-
sinusitis;however,apositivediagnosisrequiresmycologicaland
histologic studies.
53
1. Noresponsetoantibiotictherapy
2. Soft tissue changes in sinus associated with thickened reactive
bone,withlocalizedareasofosteomyelitis
3. Association of inammatory sinus disease that involves the
nasal fossa and facial soft tissue
Radiographic Appearance. Granulomatous rhinosinusitis
is extremely variable and may appear radiographically as mild
thickening(lesscommon)tocompleteopacication(morecom-
mon)ofthesinus.emajorityofsinusesshowcompleteopaci-
cation with hyperdense areas.
54
Extensionbeyondthemaxillary
sinus to other sinuses is common and expansion and erosion of a
sinus wall may be present.
Treatment. Patients with a history or current knowledge of
fungal rhinosinusitis should be referred to their physician or an
ENTfortreatmentandsurgicalclearance(i.e.,inmostcasesclear-
ance will not be given because fungal rhinosinusitis is rarely cur-
able).Treatmentusuallyinvolvesdebridementandtherapywith
anantifungalagent,suchasamphotericinB(Fig.37.19).
Cystic Lesions
Cystic type lesions are a common occurrence in the maxillary
sinus. ey may vary from microscopic lesions to large, destruc-
tive,expansilepathologicconditions.Cysticlesionsmayinclude
pseudocysts, retention cysts, primary mucoceles, and postopera-
tive maxillary cysts.
Pseudocysts (Mucous Retention Cyst)
e most common cysts in the maxillary sinus are mucous reten-
tion cysts. After much controversy, in 1984, Gardner
55
distin-
guishedthesecystsintotwocategories:(1)pseudocystsand(2)
A B
Fig. . Allergic rhinosinusitis. (A) Bilateral polypoid inflammation consistent with allergic rhinosinusitis. (B) Polyp removal on a patient
with chronic allergic rhinosinusitis. Unfortunately the polyps have a high incidence of recurrence, and in many cases this contradicts implant
treatment.
Fig. . Fungal rhinosinusitis. Coronal cone beam computerized
tomographic image of fungal rhinosinusitis, which has the radiographic
appearance of an opacified sinus with localized highly densified areas.

1004
PART VII Soft and Hard Tissue Rehabilitation
retention cysts. Pseudocysts are more common and of much
greater concern during sinus graft surgery, compared with reten-
tion cysts. Pseudocystsrecur in approximately 30% of patients
and are often unassociated with sinus symptoms. As a conse-
quence, many physicians do not treat this condition. However,
when their size is larger (approximately >10 mm in diameter),
pseudocysts may occlude the maxillary ostium during a sinus graft
procedure and increase the risk of postoperative infections. Stud-
ies have shown successful bone graft and implant placement in
maxillary sinuses with pseudocysts.
56
Etiology
Apseudocystiscausedbyanaccumulationofuidbeneaththeperi-
osteum of the sinus mucosa. is elevates the mucosa away from the
oorofthesinus,givingrisetoadome-shapedlesion.Pseudocysts
have also been termed mucosal cysts, serous cysts, and nonsecreting
cysts.Pseudocystsarenottruecystsbecausetheylackanepithelial
lining;however,theyaresurroundedbybrousconnectivetissue.
57
ecauseoftheuidisthoughttoresultfromsinusmucosabacte-
rialtoxinsorfromodontogeniccauses(Fig.37.20).
Radiographic Appearance
Pseudocysts are depicted radiographically as smooth, homog-
enous, dome-shaped, round to ovoid, well-dened radiopaci-
ties.Pseudocystsdonothaveacorticated(radiopaque)marginal
perimeterandalmostalwayslocatedontheoorofthesinuscav-
ity.Insomecases,pseudocystsmayencompasstheentiremaxillary
sinus,makingdiagnosisdicultbecauseitmayberadiographi-
cally similar to rhinosinusitis.
Treatment
Pseudocystsarenotacontraindicationforsinusgraftsurgery,unless
their approximate size increases the possibility of occluding the
maxillaryostium.Ifalargepseudocyst(i.e.,greaterthan8mm)is
present, then the elevation of the membrane during a sinus graft
mayraisethecysttooccludetheostium.Inaddition,onelevation
or placement of the grafting material, the cyst may be perforated,
allowinguidwithinthecysttocontaminatethegraft.Largecysts
of this nature should be drained and allowed to heal before or in
conjunctionwithsinuselevationsurgery.Mostoften,anENTphy-
sicianshouldevaluatetodetermineanyintervention.Ifapseudo-
cystislessthan8mm,thenlessconcernisneededandtheuid
may be drained in conjunction with sinus grafting, depending on
thesurgeonsexperienceinthetreatmentofthiscondition.Caution
shouldbeexercisedtopreventmembraneperforation.Astrictrecall
evaluation of this area during the follow-up period of the sinus graft
surgery is in order because reoccurrence of pseudocysts is common.
Retention Cysts
Retentioncystsmaybelocatedonthesinusoor,neartheostium,
or within antral polyps. Because they contain an epithelial lining,
researchersconsiderthemtobemucoussecretorycystsand“true”
cysts.Retentioncystsareoftenmicroscopicinsize.
Etiology
Retention cysts result from partial blockage of seromucinous
gland ducts located within the connective tissue underlying the
sinusepithelium.Asthesecretionscollect,theyexpandtheduct,
producing a cyst that is encompassed by respiratory or cuboidal
epithelium. ey may be caused by sinus infections, allergies, or
odontogenic reasons.
Radiographic Appearance
Retentioncystsareusuallyverysmallandnotseenclinicallyor
radiographically.Inrareinstances,theymayachieveadequatesize
tobeseeninaCTimageandmayresembletheappearanceofa
small pseudocyst.
Treatment
No treatment for retention cysts exist before or in conjunction
withasinusgraftand/orimplantinsertion.
Fluid
A
B
Fig. . Pseudocyst. (A) Diagram showing fluid accumulation underneath the membrane. (B) Radio-
graph showing the dome-shaped characteristics of a pseudocyst.

1005
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
Primary Maxillary Sinus Mucocele
Aprimarymucoceleisacystic,expansile,destructivelesionthat
may include painful swelling of the cheek, displacement of teeth,
nasal obstruction, and possible ocular symptoms.
58
e primary
mucoceleismorecommonlyfoundintheethmoidsinus(45.5%)
versusthemaxillarysinus(18.3%).
59
Etiology
e primary mucocele arises from blockage of the maxillary
ostium by brous connective tissue. Because of the compromised
drainage, the mucosa expands and herniates through the antral
walls. is mucocele is classied as a cyst because it is lined by
antral epithelium, which contains mucin.
Radiographic Appearance
Intheearlystages,theprimarymucoceleinvolvestheentiresinus
andappearsasanopaciedsinus.Asthecystenlarges,thewalls
becomethinandeventuallyperforate.Inthelatestages,destruc-
tion of one or more surrounding sinus walls is evident.
Treatment
Surgical removal of this cyst is indicated prior to any bone aug-
mentationprocedures(Fig.37.21).
Secondary Maxillary Sinus Mucocele
(Postoperative Maxillary Cyst)
A postoperative maxillary cyst of the maxillarysinus is a cystic
lesion that usually develops secondary to a previous trauma or
surgicalprocedureinthesinuscavity.Italsohasbeentermeda
surgical ciliated cyst, postoperative maxillary sinus mucocele,
or a secondary mucocele.
60-62
Secondary mucoceles occur most
commonlyinthemaxillarysinus(86%)versustheethmoidsinus
(7.1%).
59
Etiology
Apostoperativemaxillarycystisadirectresultoftraumaorpast
history of surgery within the maxillary sinus. e cyst is derived
from the antral epithelium and mucosal remnants that previ-
ously were entrapped within the prior surgical site. is separated
mucosa results in an epithelium-lined cavity in which mucin is
secreted. e antrum becomes divided by a brous septum in
which one part drains normally, whereas the other part is com-
posedofthemucocele.ItisrelativelyrareintheUnitedStates;
however,itconstitutesapproximately24%ofallcystsinJapan.
Atleastthreereportedcasesexistofapostoperativemaxillarycyst
forming after a sinus graft procedure, including one by the author
of this chapter.
63
Radiographic Appearance
e cyst radiographically presents as a well-dened radiolucency
circumscribed by sclerosis. e lesion is usually spherical in the
earlystages,withnobonedestruction.Asitprogresses,thesinus
wallbecomesthinandeventuallyperforates.Inlaterstages,itwill
appear as two separated anatomic compartments.
Treatment
Surgical ciliated cysts should be enucleated before any bone aug-
mentationprocedures.Ifobservedafterthesinusgraft,thenthe
cystsshouldbeenucleatedandregraftedinthesite(Fig. 37.22)
Neoplasms
Etiology
Primarymalignanttumorswithinthemaxillarysinusareusually
caused by squamous cell carcinomas or adenocarcinomas. Signs
and symptoms of malignant disease are related to the surround-
ing sinus wall that the tumor invades and includes swelling in the
cheek area, pain, anesthesia or paresthesia of the infraorbital nerve
(e.g.,anteriorwall),andvisualdisturbances(e.g.,superiorwall).
ese tumors in the sinus are usually nonspecic and give a variety
Fluid
A
B
Fig. . Primary maxillary sinus mucocele. (A) Diagram showing expansive nature of a primary maxil-
lary sinus mucocele. (B) Radiograph showing the initial stage of complete opacification and later stages
including expansion of the bony plates.

1006
PART VII Soft and Hard Tissue Rehabilitation
ofconsequences,includingopaciedsinuses;softtissuemassesin
thesinus;andsclerosis,erosion,ordestructionofthewallsofthe
sinus. Sixty percent of squamous cell carcinomas of the parana-
sal sinuses are located in the maxillary sinus, usually in the lower
one-halfoftheantrum.Clinicalsignsintheoralcavityreectthe
expansion of the tumor and an increased mobility of the involved
teeth.Invasionoftheinfratemporalfossaisalsopossible.
1
Radiographic Appearance
Radiographicsignsofneoplasmsmayincludevarious-sizedradi-
opaquemasses,completeopacication,orbonywallchanges.A
lack of a posterior wall on a panoramic radiograph should be a
signofpossibleneoplasm(Fig. 37.23).
Treatment
Anysignsorsymptomsofalesionofthistypeshouldbeimmedi-
ately referred for medical consultation. Sinus graft surgery is abso-
lutely contraindicated while this condition exists.
Antroliths and Foreign Bodies
Maxillary sinus antroliths are the result of complete or partial
encrustation of a foreign body. ese masses found within the
maxillary sinus originate from a central nidus, which can be
endogenous or exogenous.
64
Etiology
e majority of endogenous sources are from dental origin,
including retained roots, root canal sealer, fractured dental instru-
ments,anddentalimplants. Additionally, bone spicules,blood,
and mucus have been reported to cause antroliths.
65
Reportsin
the literature of exogenous sources include paper, cigarettes, snu,
and glue.
66
Although most antroliths are asymptomatic, they
often are associated with sinusitis.
Radiographic Appearance
e radiographic appearance of a maxillary antrolith resembles
eitherthecentralnidus(e.g.,retainedroot)orappearsasaradi-
opaque,calciedmasswithinthemaxillarysinus(Fig.37.24).
Differential Diagnosis
Because the calcied antrolith is composed of calcium phosphate
(CaPO
4
),calciumcarbonatesalts,water,andorganicmaterial,it
willbe considerably moreradiopaque than an inammatory or
cystic lesion.
67
e central nidus of the antrolith is similar to its
usual radiographic appearance.
Fluid
BA
C D
Fig. . Secondary maxillary sinus mucocele. (A) Diagram showing cystic nature of a secondary
mucocele, which divides the sinus into two compartments. (B) Radiograph of blade implant with well-
defined radiolucency around the implant. (C) Blade implant removed with associated pathology. (D) Histol-
ogy revealing a secondary maxillary sinus mucocele.

1007
CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery
Treatment
Before sinus augmentation and implant placement, the antrolith
shouldbesurgicallyremoved.Ifsinusitisexists,thenthesinuscav-
ity should be allowed to heal completely before sinus augmen-
tation procedures. A nonsymptomatic condition may have the
antrolith removed and sinus graft performed at the same surgery,
only if the sinus membrane is not compromised.
Miscellaneous Factors That Affect the Health
of the Maxillary Sinus
Smoking
e use of tobacco is one of the main factors that may lead to
an increased morbidity after sinus graft procedures. Smoking is
known to be associated with an increased susceptibility to aller-
gies and infections because it interferes with ciliary function and
secretoryimmunityofthenasorespiratorytract.Inthemaxillary
sinus, this may have direct eects on both immune exclusion and
suppressionbecauseIgAandIgMresponsesarereduced,whereas
IgE responses are increased. Smoking is believed to interfere
with bone graft healing because it reduces local blood ow by
increasing peripheral resistance and causing an increased platelet
aggregation. By-product chemicals of smoking, such as hydrogen
cyanide and carbon monoxide, have been shown to inhibit wound
healing, as does nicotine, which inhibits cellular proliferation.
Tobacco may interfere directly with osteoblastic function, and
strong evidence exists of decreased bone formation in smokers.
Inaddition,smokershaveasignicantreductionofbonemineral
content. Bone mineral density can be reduced two to six times
in a chronic smoker. Overall, smoking may contribute to poor
available bone quality and poor healing capacity resulting from
vascular and osteoblastic dysfunction.
68
ere exist many clinical studies with smoking and sinus
graft procedures. Klokkevold evaluated the success rate of dental
implantsplacedintheposteriormaxilla;itshoweda7%greater
failure rate compared with nonsmokers.
69
Lindquist showed that
smokers can also suer detrimental eects around successfully
integrated maxillary implants, with a signicantly greater bleed-
ing index, greater mean peri-implant pocket depth, more frequent
peri-implant inammation, and radiographically greater mesial
and distal bone loss.
70
Olson and colleagues found an association
between dental implants placed in augmented maxillary sinuses
and history of smoking.
71
Widmarkreportedahigherfailurerate
in smokers after rehabilitation of severely resorbed maxillae with
and without bone graft.
72
Schwartz-Aradandcolleaguesevaluated
212implantsintheposteriormaxilla,resultingina95.5%success
rate with nine failures. Of the nine failures, ve were in patients
that smoked.
73
Insummary,smokingisnotanabsolutecontraindicationfor
sinus graft procedures. However, patients should be instructed to
cease smoking before and after sinus graft procedures because of
the literature-based studies showing a higher risk of wound dehis-
cence,graftinfectionand/orresorption,andareducedprobability
ofosseointegration.Itisrecommended,however,thatifadecision
to proceed with surgery has been made, then patients refrain from
smokingatleast15daysbeforesurgery(i.e.,thetimeittakesfor
nicotinetoclearsystemically)and4to6weeksaftersurgery.More-
over, smokers should sign a detailed informed consent in which
risks connected to smoking are clearly dened and explained.
Relative and Absolute Contraindication to
Maxillary Sinus Graft Procedures
In general contraindications for implant surgery also apply to
sinus graft procedures. However, additional specic and local
conditions may exist that increase morbidity. Several conditions
related to the maxillary sinus are a concern, but they are not neces-
sarily contraindications to the sinus graft procedure. e implant
clinician,afterevaluationoftheCBCTscanandevaluationofthe
maxillary sinus, will in some cases need further medical evalua-
tion before proceeding with procedures that may invade the sinus
proper. ere exists a wide variation in the severity of the possible
pathologic conditions that may be present in the maxillary sinus.
For example, a patient may have a mild deviated septum. Because
it does not aect the mucociliary clearance of the maxillary sinus
Fig. . Axial contrast-enhanced computerized tomography (bone
window) shows almost complete radiopacification of the right maxillary
sinus by squamous cell carcinoma. There is destruction of the walls of
the sinus and an air-fluid interface in the left sinus. (From Koenig LJ, etal.
Diagnostic Imaging: Oral and Maxillofacial. 2nd ed. Philadelphia, PA: Else-
vier; 2017.)
Fig. . Antroliths. Any object left in the sinus will calcify and is termed
an antrolith. Antroliths usually will result in mucociliary clearance issues.

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98737Maxillary Sinus Anatomy, Pathology, and Graft SurgeryRANDOLPH R. RESNIK AND CARL E. MISCHThe posterior maxilla has been described as one of the most challenging and complex intraoral regions that confronts the implant clinician. ere exist many treatment planning and patient factors that contribute to these problems in this area, which in many cases require the clinician to have additional train-ing and an increased skill set:• Poorbonedensity• Compromisedavailablebone• Increasedpneumatizationofthemaxillarysinus• Increasedcrownheightspace• Ridgepositionshiftstowardlingual(medial)• Dicultaccessbecauseofanatomiclocation• Increasedbitingforce• RequirementofwiderdiameterimplantsandincreasednumberBefore discussing the various treatment options of the pos-terior maxilla, it is imperative that the implant clinician have a strong foundation for maxillary sinus anatomy, anatomic variants, pathology, and a comprehensive understanding of the various treatment approaches.Maxillary Sinus Anatomye maxillary sinuses were rst illustrated and described by Leonardo DaVinciin1489andlaterdocumentedbytheEnglishanatomistNathaniel Highmore in 1651.1 e maxillary sinus, or antrum of Highmore, lies within the body of the maxillary bone and is the larg-estandrsttodevelopoftheparanasalsinuses(Fig.37.1).Adultmax-illary sinuses are pyramid-shaped, air-lled cavities that are bordered by the nasal cavity. ere is much debate about the actual function ofthe maxillarysinus.Possibletheorizedrolesofthe sinusincludeweight reduction of the skull, phonetic resonance, participation of warminghumidicationofinspiredair,andolfaction.Abiomechani-cal adaptation of the maxillary sinus directs forces away from the orbit and cranial cavity when a force is delivered to the midface.Development and Expansion of the Maxillary SinusAprimarypneumatizationoccursatapproximately3monthsoffetal development by an outpouching of the nasal mucosa within theethmoidinfundibulum.Atthattime,themaxillarysinusisabud situated at the infralateral surface of the ethmoid infundibu-lumbetweentheupperandmiddlemeatus.Prenatally,asecond-arypneumatizationoccurs.Atbirth,thesinusisstillanoblonggroove on the mesial side of the maxilla just above the germ of the rst deciduous molar.2Atbirth,thesinuscavitiesarelledwithuid.Postnatallyanduntil the child is 3 months old the growth of the maxillary sinus is closelyrelatedtothepressureexertedbytheeyeontheorbitoor,the tension of the supercial musculature on the maxilla, and theformingdentition.Astheskullmatures,thesethreeelementsinuenceitsthree-dimensional(3D)development.At5months,the sinus appears as a triangular area medial to the infraorbital foramen.3Duringthechild’srstyear,themaxillarysinusexpandslat-erally underneath the infraorbital canal, which is protected by a thin bony ridge. e antrum grows apically and progressively replaces the space formerly occupied by the developing dentition. egrowthinheightisbestreectedbytherelativepositionofthesinusoor.At12yearsofage,pneumatizationextendstotheplaneofthelateralorbitalwall,andthesinusoorislevelwiththeoorofthenose.Duringlateryears,pneumatizationspreadsinferiorly as the permanent teeth erupt. e adult sinus has a vol-umeofapproximately15mL(34mmheightx33lengthx23mmwidth).emaindevelopmentoftheantrumoccursastheper-manentdentitioneruptsandpneumatizationextendsthroughoutthebodyofthemaxillaandthemaxillaryprocessofthezygomaticbone.Extensionintothealveolarprocesslowerstheoorofthesinusapproximately5mm.Anteroposteriorly,thesinusexpansioncorresponds to the growth of the midface and is completed only with the eruption of the third permanent molars when the young personisabout16to18yearsofage.4Intheadult,thesinusispyramidshapedwithconsistingoffourbony walls, the base of which faces the lateral nasal wall and the apexofwhichextendstowardthezygomaticbone(Fig. 37.2).eoorofthemaxillarysinuscavityisreinforcedbybonyormem-branous septa, joining the medial or lateral walls with oblique or transverse buttress-like webs. ey develop as a result of genetics and stress transfer within the bone over the roots of teeth. ese have the appearance of reinforcement webs in a wooden boat and 988PART VII Soft and Hard Tissue Rehabilitationrarely divide the antrum into separate compartments. ese ele-ments are present from the canine to the molar region and tend to disappear in the maxilla of the long-term edentulous patient when stresses to the bone are reduced. Karmody found that the most common oblique septum is located in the superior anterior corner ofthesinusorinfraorbitalrecess(whichmayexpandanteriorlytothenasolacrimalduct).5 e medial wall is juxtaposed with the middle and inferior meatus.Althoughthemaxillary sinus maintains its overallsizewhilethe teeth are present, an expansion phenomenon of the maxil-lary sinus occurs with the loss of posterior teeth.6 e antrum expands in both inferior and lateral dimensions. is expansion may even invade the canine eminence region and proceed to the lateral piriform rim of the nose. e dimension of available bone height of the posterior maxilla is greatly reduced as a result of dual resorptionfromthecrestoftheridgeandpneumatizationofthesinus after the loss of teeth. e sinus expansion is more rapid than thecrestalboneheightchanges.Asaresultoftheinferiorsinusexpansion, the amount of available bone in the posterior maxilla greatlydecreasesinheight(Fig. 37.3).emaxillarysinustendsto enlarge with age, as well as with edentulism, which further 11234• Fig. . Maxillary sinus (1) is the largest of the four paranasal sinuses. The initial maxillary sinus formation is completed at age 16 to 18 years. 2, Frontal sinus; 3, ethmoid sinus; 4, sphenoid sinus.OrbitMiddlemeatusMaxillarysinusat birthMaxillarysinusevolutionToothSphenoethmoidal sinusFrontalsinusCristagalliSuperiormeatusFrontonasalduraNasalseptumNasalfossaInferiormeatus• Fig. . Maxillary sinus begins to form in the fetus and by 5 months is the size of a pea, under the eye, and close to the ostium for drainage. By 16 years of age, the maxillary sinus has four thin, bony walls around it. The superior wall separates it from the floor of the orbit. The medial wall contains the ostium to drain the sinus and separates it from the nasal fossa. The lateral wall forms the maxillary bone below the zygomatic arch. The floor of the antrum rests above the roots of the teeth. 989CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerydecreasestheamountofavailablebone.Inadditiontothedimin-ished quantity, bone in the posterior maxilla often is softer and of poorerquality.Radiographstypicallyrevealsparsetrabeculations,and the tactile experience of drilling in this bone resembles a Sty-rofoamtypeofmaterial(D4Bone).Afternormalsinusexpansion,withperiodontaldiseaseandtoothloss increasing the bone loss, inadequate bone will result between thealveolarridgecrestandtheoorofthemaxillarysinus.Inmostcases, bone quantity will be compromised for implant placement. e limited available bone is compounded by a decrease in bone density and the shifting of the residual ridge in a medial direction. erefore this area of the maxilla is often reported with an increased incidence of implant malpositioning and morbidity. Bone Resorption Processe maxilla generally has a thinner cortical plate facially compared with any region of the mandible, and very minimal cortical bone is presentontheridge.Inaddition,thetrabecularboneintheposteriormaxillaisner(lessdense)thanotherdentateregions.Whenmaxil-lary posterior teeth are lost, an initial decrease in bone width at the expense of the labial bony plate results. e width of the posterior maxilla has been shown to decrease at a more rapid rate than in any other region of the jaws.7 e resorption phenomenon is accelerated bythelossofvascularizationofthealveolarboneandtheexistingne trabecular bone type. However, because the initial residual ridge is inherently wide in the posterior maxilla, even with a signicant decrease in the width of the ridge, adequate-diameter root-form implants(∼5mm)usually canbeplaced. However, astheresorp-tion process continues, the residual ridge continues to progressively shift toward the palate until the ridge is signicantly resorbed into a medially positioned narrower bone volume.8 is results in the buc-cal cusp and central fossa of the nal restoration being cantilevered facially to satisfy esthetic requirements at the expense of biomechan-ics in the moderate to severe atrophic ridges. is cantilevered part of the prosthesis is usually in the form of a ridge lap pontic area, whichinmostcasesresultsinhygienediculties. Resultant Poor Bone DensityIngeneral,thebonequalityis poorestinthe posteriormax-illa, compared with any other intraoral region.9 A literaturereview of clinical studies reveals that the poorest bone density maydecreaseimplantloadingsurvivalbyanaverageof16%,andithasbeenreportedaslowas40%.10 e cause of these failures is related to several factors. Bone strength is directly related to its density, and the poor-density bone of this region isoften5to10timesweaker,comparedwithbonefoundintheanteriormandible.Bonedensitiesdirectlyinuencethebone-to-implantcontactpercentage(BIC),whichaccountsfortheforcetransmissiontothebone.eBICisleastinD4bone,and the stress patterns in this bone migrate farther toward the apexoftheimplant(Fig.37.4).Asaresult,bonelossismorepronounced and also occurs along the implant body, rather than only crestally, as in other denser bone conditions. D4bone also exhibits the greatest biomechanical elastic modulus dierence compared with titanium under load.11Earlierstud-ies and surgical protocols did not take into consideration the poorBICinthisarea.Intheposteriormaxilla,thedecientosseousstructuresandan absence of cortical plate on the crest of the ridge is often observed, which further compromises the initial implant stabil-ity at the time of insertion. e labial cortical plate is thin, and theridgeisoftenwide.Asaresult,thelateralcorticalBICtosta-bilizetheimplantisofteninsignicant.eimplantplacementprotocoloftenusesbonecompression(osseodensication)ratherthanboneextraction(removal)tocreatetheimplantosteotomytocompensateforthesedeciencies.Ifthesurgicalprotocolisnotmodied,theinitialhealingofanimplantinD4bonewillbe compromised. 123334AB• Fig. . (A) The fourth expansion phenomenon of the maxillary sinus occurs with the loss of the poste-rior teeth. The anterior portion of the sinus may expand to the piriform rim of the nose. The inferior expan-sion may approach the crest of the ridge. 1, Maxillary sinus; 2, frontal sinus; 3, ethmoid sinus; 4, sphenoid sinus. (B) Coronal section of the posterior region of the edentulous human maxilla. Note expansion of the sinus floor inferiorly far below the level of the floor of the nose. The alveolar ridge bone is markedly atrophied, whereas the ridge submucosa has become fibrotic. Stained with Rescorcin Fuchsin stain and counterstained with Ban Gieson. (Courtesy Mohamed Sharawy, Augusta, Georgia.) 990PART VII Soft and Hard Tissue RehabilitationBony Wallse maxillary sinus features six bony walls, each of which contain important anatomic structures that play a signicant role in the treatment of the maxillary posterior region. e implant clinician must have a strong understanding and foundation of the bony walls associated with the posterior maxilla in the preoperative assessmentbeforesurgicalprocedures(Fig.37.5)Anterior Walle anterior wall of the maxillary sinus consists of thin, compact bone extending from the orbital rim to just above the apex of thecuspid.Withthelossofthecanine,theanteriorwalloftheantrummayapproximatethecrestoftheresidualridge.Withintheanteriorwallandapproximately6to7mmbelowtheorbitalrim,withanatomicvariantsasfaras14mmfromtheorbitalrim,is the infraorbital foramen (Fig. 37.6A). e infraorbital nerveruns along the roof of the sinus and exits through the foramen. e infraorbital blood vessels and nerves lie directly on the supe-rior wall of the maxillary sinus and within the sinus mucosa.Tenderness to pressure over the infraorbital foramen or redness oftheoverlyingskinmayindicateinammationofthesinusmem-brane from infection or trauma, which may contraindicate graft surgeryuntilresolution.Inpatientsexhibitinganatomicvariantsof the infraorbital foramen, neurosensory impairment may occur during retraction of this area, leading to neurapraxia type injuries. e use of worn, sharp-edged retractors should be avoided when reectingtissuesuperiorlyinthisareatoavoidpotentialinjuries.Within the anterior wall of the sinus, the thinnest part is thecanine fossa, which is directly above the canine tooth. e anterior wall of the maxillary sinus may also serve as surgical access during Caldwell-Lucprocedurestotreatapreexistingorpost–sinusgraft,pathologic condition. Superior Walle superior wall of the maxillary sinus coincides with the thin inferiororbitaloor.eorbitaloorslantsinferiorlyinamedio-lateral direction and is convex into the sinus cavity.Abonyridgeisusuallypresentinthiswallthathousestheinfra-orbital canal, which contains the infraorbital nerve and associated bloodvessels.Dehiscenceofthebonychambermaybepresent,resulting in direct contact between the infraorbital structures and the sinus mucosa.Ocular symptoms may result from infections or tumors in the superior aspects of the sinus region and may include proptosis (bulging of the eye) and diplopia (double vision). When theseproblems occur, the patient is closely supervised, and a medical consult is advised to decrease the risk of severe complications that may result from the spread of infection in a superior direction. Superior-spreading infections may lead to signicant ocular prob-lemsorbrainabscesses.Asaresult,whenocularorcerebralsymp-toms appear, aggressive therapy to decrease the spread of infection is indicated. Overpacking the maxillary sinus with bone graft material during a sinus graft may result in pressure against the superiorwallifasinusinfectiondevelops(seeFig.37.6B). Posterior Walle posterior wall of the maxillary sinus corresponds to the pterygomaxillary region, which separates the antrum from the infratemporal fossa. e posterior wall usually has several vital structures in the region of the pterygomaxillary fossa, including the internal maxillary artery, pterygoid plexus, sphenopalatine ganglion, and greater palatine nerve. e posterior wall should always be identied radiographically because when the wall is not present,apathologiccondition(includingneoplasms)istobesus-pected(seeFig.37.6C).Commondonorsitestoobtainautogenousboneforsinusaug-mentation procedures include the tuberosity area. Special consid-eration should be taken for the posterior extent of the tuberosity removal. Aggressivetuberosity removalmay lead to bleeding intheinfratemporalfossa(pterygoidplexus),resultinginlife-threat-ening situations.It should be noted that pterygoid implants placed throughthe posterior sinus wall and into this region may approach vital structures,includingthemaxillaryartery.Ablindsurgicaltech-nique to place a pterygoid implant through the posterior wall may have increased surgical risk. However, they are of benet primarily • Fig. . Bone–implant contact percent is often reduced in the posterior maxilla because the quality of bone is poorer than other regions of the mouth. This histologic slide depicts the numerous areas of no bone con-tact at the implant interface.• Fig. . Maxillary sinus is comprised of six walls that contain significant anatomic and vital structures, which are important in the placement of implants. 1, Lateral, 2, anterior, 3, medial, 4, posterior, 5, inferior, 6, superior. 991CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerywhen third or fourth molars are needed for prosthetic reconstruc-tion or sinus grafts are contraindicated and available bone poste-rior to the antrum is present. Medial Walle medial wall of the antrum coincides with the lateral wall of the nasal cavity and is the most complex of the various walls of the sinus. On the nasal aspect, the lower section of the medial wall parallelsthelowermeatusandoorofthenasalfossa;theupperaspect corresponds to the middle meatus. e medial wall is usu-allyverticalandsmoothontheantralside(seeFig.37.6D).e main drainage avenue of the maxillary sinus is through the maxillary ostium. e primary ostium is located in the superior aspect of the sinus medial wall and drains its secretions via the ethmoid infundibulum through the hiatus semilunaris into the middle meatus of the nasal cavity. e infundibulum is approxi-mately5to10mmlonganddrainsviaciliaryactioninasuperiorandmedialdirection.eostiumdiameteraverages2.4mminhealth;however,pathologicconditionsmayalterthesizetovaryfrom1to17mm.12e maxillary ostium and infundibulum are part of the ante-rior ethmoid middle meatal complex, the region through which AA BCEFD• Fig. . Six bony walls of the maxillary sinus. (A) Anterior. (B) Superior. (C) Posterior. (D) Medial. (E) Lateral. (F) Inferior. 992PART VII Soft and Hard Tissue Rehabilitationthe frontal and maxillary sinuses drain, which is primarily respon-sible for mucociliary clearance of the sinuses to the nasopharynx. Asaresult,obstructioninoneormoreareasofthecomplexwillusually result in rhinosinusitis or lead to morbidity of the graft or implant.Patencyofthemaxillaryostiumismostcrucialpreop-eratively and postoperatively during maxillary graft sinus surgery to preventinfection and morbidity of the graft. Evaluatingthepatencyoftheostiumviaconebeamcomputerizedtomography(CBCT) is easily accomplished with evaluation of serial cross-sectional images. e patency of the ostium must be ascertained before surgery to prevent or minimize postoperative complica-tions. is is easily veried via coronal or cross-sectional images on CBCT surveys. Of utmost importance when performingany procedure involving the maxillary sinus, the patency of the ostium must be maintained throughout the postoperative period. If ostium patency is compromised, increased morbidity of theimplant or graft will occur because the mucociliary action of the maxillary sinus will be compromised.Smaller, accessory or secondary ostia may be present that are usually located in the middle meatus posterior to the main ostium. ese additional ostia are most likely the result of chronic sinus inammationandmucousmembranebreakdown.eyarepres-ent in approximately 30% of patients, ranging from a fractionofamillimeterto0.5cm,andarecommonlyfoundwithinthemembranous fontanelles of the lateral nasal wall.13 Fontanelles are usuallyclassiedeitherasanteriorfontanelles(AFs)orposteriorfontanelles(PFs)andaretermedbytheirrelationtotheuncinatedprocess. ese weak areas in the sinus wall are sometimes used to create additional openings into the sinus for treatment of chronic sinusinfections.Primaryandsecondaryostiamay,onoccasion,combine and form a large ostium within the infundibulum. Lateral Walle lateral wall of the maxillary sinus forms the posterior max-illaandthezygomaticprocess.iswallvariesgreatlyinthick-ness from several millimeters in dentate patients to less than 1mminanedentulouspatient.ACBCTexaminationwillrevealthe osseous thickness of the lateral wall, which is crucial in den-ing the osteotomy location and preparation technique. Patientsexhibiting increased parafunction forces will have thicker lateral walls (see Fig.37.6E). e lateral wall thickness of the maxillahas been noted to be extremely variable, with some cases being nonexistent. is will lead to an increased possibility of membrane perforation,evenoccurringonreection.Incontrast,thelateralwall may be very thick, which is usually seen with patients that exhibit parafunction and have just recently lost the posterior teeth. Inthese situations, lateral wallsinusgraftingbecomes verydif-cult because of the cortical thickness. e lateral wall houses the intraosseous anastomosis of the infraorbital and posterior superior alveolar artery, which may lead to a bleeding complication because this area is the site for osteotomy preparation of the lateral wall sinus graft procedure. Inferior Walleinferiorwalloroorofthemaxillarysinusisincloserelation-ship with the apices of the maxillary molars and premolars. e teeth usually are separated from the sinus mucosa by a thin layer ofbone;however,onoccasion,teethmayperforatetheoorofthesinus and be in direct contact with the sinus lining. Studies have shown that the rst molar has the most common dehiscent tooth root,occurringuptoapproximately30%to40%ofthetime.14 Indentatepatientsthesinusoorisapproximatelyatthelevelofthenasaloor.Intheedentulousposteriormaxillathesinusoorisoften1cmbelowthelevelofthenasaloor(seeFig.37.6F).Radiographically,thesinusinferioroormorphologyiseasilyseenvia3Dimaging.eoorisrarelyatandsmooth;thepres-ence of irregularities and septa should be determined and their exact locations noted. Irregularoors are most often seen afterteeth are extracted, leaving residual bony crests that increase risk ofperforationbecauseofthe dicultyinmembrane reection.Insomecases,thebonycrestsarenotevenseen onthe CBCTevaluation.Complete or incomplete bony septa may exist on the oorinaverticalorhorizontalplane.Approximately30%ofdentatemaxillae have septa, with three-fourths appearing in the premo-lar region. Complete septa separating the sinus into compart-mentsareveryrare,occurringinonly1.0%to2.5%ofmaxillarysinuses.15 e presence of septa complicate lateral wall sinus graft procedures, which leads to an increased likelihood of membrane perforation. Ostiomeatal Complexe ostiomeatal unit is composed of the maxillary ostium, eth-moid infundibulum, anterior ethmoid cells, hiatus semilunaris, and the frontal recess, which encompasses the area of the middle meatus.iscommonchannelallowsforairowandmucociliarydrainage of the frontal, maxillary, and anterior ethmoid sinuses. Blockage in this area leads to impaired drainage of the maxil-lary, frontal, and ethmoid sinuses, which may result in rhinosi-nusitis and postoperative complications after implant or grafting procedures.Radiographic identication of the ostiomeatal complex andrelated structures must be evaluated to prevent potential postopera-tivecomplications.Pathologyorvariationswithintheostiomeatalcomplex may lead to postoperative sinus graft morbidity or implant complicationscausedbycompromisedmucociliarydrainage(alter-ationofnormalsinusphysiology)ofthemaxillarysinus. Blood Supply and Sensory Innervatione vascular supply in the maxillary sinus is a vital part of the healing and regeneration of bone after a sinus graft and healing of a dental implant. e blood supply to the maxillary sinus is derived from the maxillary artery, which emanates from the exter-nal carotid artery. e maxillary artery supplies the bone sur-rounding the sinus cavity and also the sinus membrane. Branches of the maxillary artery, which most often include the posterior superior alveolar artery and infraorbital artery, form endosseous and extraosseous anastomoses that encompass the maxillary sinus. e formation of the endosseous and extraosseous anastomoses in the maxillary sinus is termed the double arterial arcade. Studies haveshownvascularizationofpostgraftmaterialtodependontheintraosseous and extraosseous anastomoses, along with the blood vessels of the Schneiderian membrane, which is supplied by the posterior superior alveolar artery and the infraorbital artery along the lateral wall.16ereexistdierentfactorsthatalterthevascularizationinthisarea.Withincreasingage,thenumberand sizeofbloodvesselsinthemaxilladecrease.Asboneresorptionincreases,thecorticalbonebecomesthin,resultinginlessvascularization.Asthelateralwall becomes thinner, the blood supply to the lateral wall and lat-eral aspect of the bone graft comes primarily from the periosteum, resultinginacompromisedvascularizationtotheregion. 993CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryExtraosseous Anastomosiseextraosseousanastomosisisfoundinapproximately44%ofthe population and is usually in close approximation to the peri-osteum of the lateral wall.e extraosseous anastomosis is superior to the endosseous unit,whichisapproximately15to20mmfromthedentatealveo-larcrest.Tominimizevasculartraumatotheextraosseousanasto-mosis, surgical and anatomic considerations should be addressed. Ideally,verticalincisionsshould bemadeasshortaspossibletodecreasethepossibilityofbloodvesseldamage.Itiscrucialtogainadequate access to the lateral aspect of the maxilla, and the perios-teumshouldbereectedfullthicknesswithgreatcare.Haphazardreectionmayleadtoseveringordamagetotheanastomosis,withresultant postoperative edema. Severing of the extraosseous anas-tomosis may result in signicant increased bleeding during the surgical procedure. is intraoperative complication may give rise to impaired visibility for the clinician, along with increased sur-geryduration.Additionally,postoperativecomplicationssuchaspain, edema, and ecchymosis may result from the severing of these bloodvessels.Iftraumatothesevesselsoccurs,directpressureorthe use of electrocautery may be used. However, electrocautery may potentiallycausemembranedamageornecrosis.Ifseverebleed-ing occurs, curved Kelly hemostats are used to clamp the bleeding vessel,followedbyligatureplacement.AslowlyresorbablesuturewithhightensilestrengthsuchasVicrylisrecommended. Intraosseous Anastomosise intraosseous anastomosis is found within the lateral wall of the sinus,whichsuppliesthelateralwallandthesinusmembrane.Inan edentulous maxilla with posterior vertical bone loss, the endos-seousanastomosismaybe5to10mmfromtheedentulousridge.eendosseousarteryhasbeenshowntobeobservedonCBCTscans in approximately one-half of the patients requiring a sinus graft.17 However, anatomic cadaver studies have shown the preva-lencetobe100%.17In82%ofcases,themostcommonanatomiclocation was observed between the canine and second premolar region.18 However, with a long-term edentulous patient with a thin lateral wall, the artery may be atrophied and almost nonexistent.Surgical, radiographic, and anatomic considerations should be addressedtominimizetraumatothesebloodvessels.eCBCTradiographic identication is extremely important in identifying these blood vessels before surgery so preparation may be made. Radiographically,smalleranastomoseswillnotbeseenifthepixelsize(∼1.0mm)islessthanone-halfthesizeoftheanastomosisvessel.Studieshaveshownthattheuseofa0.3or0.4CBCTpixelsizeforradiographicevaluationwillmostlikelyshowthesmalleranastomoses.19Studies have shown that in 20% of lateral wall osteoto-mies signicant bleeding complications may occur,20 mainly becausetheanastomosisisgreaterthan1.0mmindiameter.Ithasbeen shownthatvessels larger than1.0mmare moreproblematic and associated with signicant bleeding, whereas smallervessels(<1.0mm)areusuallyinsignicantandeasilymanaged(Fig. 37.7;Box37.1).Inmost cases, bleeding is a minor complication and of shortduration; however, in some instances it may be signicant anddicultto manage.To controlbleeding, therearemany possibletreatments:(1)thepatientshouldberepositionedintoanuprightACInfraorbitalarteryMaxillary arteryPosteriorsuperior arteryIntraosseousbranch of PSADB• Fig. . Blood supply of the maxillary sinus. (A) Extraosseous and intraosseous anastomosis, which is made up of the infraorbital and posterior superior artery. (B) Cross-sectional cone beam computerized tomography image depicting intraosseous anastomosis (arrow). (C) Intraosseous notch (arrow) containing the intraosseous anastomosis, which comprises the posterior superior artery and infraorbital artery. (D) Pos-terior lateral nasal artery location in the medial wall of the maxillary sinus. PSA, Posterior Superior Artery. 994PART VII Soft and Hard Tissue Rehabilitationpositionandpressureappliedwithasurgicalgauze;(2)electrocau-tery may be used, although this may lead to membrane necrosis and perforation,withpossiblemigrationofgraftmaterial;(3)asecondwindow may be made proximal to the bleeding source to gain access to the bleeding vessel, especially if location cannot be obtained from the original window;and(4) cutting the bone and vessel with ahigh-speeddiamondwithnoirrigation(whichcauterizesthevessel). Posterior Lateral Nasal ArteryA posterior lateral nasal artery (branch of the sphenopalatinearterythatalsorisesfromthemaxillaryartery)suppliesthemedialaspect of the sinus cavity. e medial and posterior walls of the maxillary sinus mucosa receive their blood supply from the poste-rior lateral nasal artery.During sinus graft surgery the clinician may be in closeapproximation to this artery when elevating the membrane o the medialwall.Careshouldbeexercisedtominimizetraumatothisareabecauseaggressivereectionofthemembranemayresultintrauma to the blood vessel or perforation into the nasal cavity.Trauma to this artery may cause signicant bleeding in the sinus proper and also within the nasal cavity. Because the medial sinuswallisverythin(usuallyone-halfthethicknessofthelateralwall),aggressivemembranereectionmayresultintrauma,lead-ing to bleeding issues. Sphenopalatine/Infraorbital Arteriese sphenopalatine artery is also a branch of the maxillary artery and enters the nasal cavity through the sphenopalatine foramen, which is near the posterior portion of the superior meatus of the nose.Asthesphenopalatinearteryexitstheforamen,itbranchesintothe posterior lateral nasal artery and the posterior septal artery.21 Additionally,theinfraorbitalarteryentersthemaxillarysinusviatheinfraorbital ssure in the roof of the sinus and ascends cranially into the orbital cavity. Because of the anatomic locations of these blood vessels, it is rarely a concern with respect to sinus graft surgery.e sphenopalatine and infraorbital blood vessels are usually not problematic for bleeding complications during lateral-approach sinus elevation surgery because of their anatomic locations. How-ever, incorrect incision locations and aggressive reection maydamagethebloodvessels.Ifbleedingdoesoccur,itisusuallyeasilycontrolled with pressure and local hemostatic agents. Maxillary Sinus Mucosae epithelial lining of the maxillary sinus is a continuation of the nasal mucosa and is classied as a pseudostratied, ciliated colum-nar epithelium, which is also called the respiratory epithelium.e epithelial lining of the maxillary sinus is much thinner and contains fewer blood vessels than the nasal epithelium. is accountsforthemembrane’spalecolorandbluishhue.Fivepri-marycelltypesexistinthistissue:(1)ciliatedcolumnarepithelialcells,(2)nonciliatedcolumnarcells,(3)basalcells,(4)gobletcells,and (5) seromucinous cells. e ciliated cells contain approxi-mately50to200ciliapercell.Inahealthymaxillarysinusthecilia cells assist in clearing mucus from the sinus and into the naso-pharynx. e nonciliated cells compose the apical aspect of the membrane, contain microvilli, and serve to increase surface area. ese cells have been theorized to facilitate humidication andwarmingofinspiredair.ebasalcell’sfunctionissimilartothatof a stem cell that can dierentiate as needed. e goblet cells in the maxillary sinus produce glycoproteins that are responsible for the viscosity and elasticity of the mucus produced. e maxillary sinus contains the highest concentration of goblet cells compared with the other paranasal sinuses. e maxillary sinus membrane alsoexhibitsfewelasticbersattachedtothebone(notenaciousattachmentisusuallypresent),whichsimplieselevationofthistissue from the bone during grafting procedures. e thickness ofthesinusmucosainhealthvaries,butitisgenerally0.3to0.8mm.22Insmokers,itvariesfromverythinandalmostnonexistentto very thick, with a squamous type of epithelium.Radiographically, normal, healthy paranasal sinuses reveal acompletely radiolucent (dark) maxillary sinus. Any radiopaque(whitish)areawithinthesinuscavityisabnormal,andapatho-logic condition should be suspected. e normal sinus membrane isradiographicallyinvisible,whereasanyinammationorthick-ening of this structure will be radiopaque. e density of the dis-easedtissueoruidaccumulationwillbeproportionaltovaryingdegrees of gray values.Maintaining the integrity of the sinus membrane is crucial in decreasing postoperative complications, including loss of graft material and the possibility of infection.Many factors may alter the physiology of the sinus mucosa, such as viruses, bacteria, and foreign bodies (implants). Careshouldbetakentominimizemembraneperforationsduringsur-gery.Ifperforationsoccur,appropriaterepairtreatmentprotocolsshould be followed. Maxillary Sinus Mucociliary ClearanceNormal mucociliary ow is crucial to maintaining the healthyphysiologyofthe maxillary sinus.Inahealthysinusanadequatesystem of mucus production, clearance, and drainage is maintained. e key to normal sinus physiology is the proper function of the cilia, which is the main component of the mucociliary transport system. e cilia move contaminants toward the natural ostium and then to the nasopharynx. e cilia of the columnar epithelium beat towardtheostiumatapproximately15cyclesperminute,withasti stroke through the serous layer, reaching into the mucoid layer. ey recover with a limp reverse stroke within the serous layer. is mechanism slowly propels the mucoid layer toward the ostium at a rateof9mmperminuteandintothemiddlemeatusofthenose.22Inhealth, mucoid uid is transported towardtheostium ofthe maxillary sinus and drains into the nasal cavity, eliminating inhaled small particles and microorganisms. is mucociliary transport system is an active transport system that relies heavily on oxygen. e amount of oxygen absorbed from the blood is not adequatetomaintainthisdrainagesystem;additionaloxygenhasto be absorbed from the air in the sinus. is is why the patency of the ostium is crucial in maintaining the normal transport system.• Endosseousanastomosis(withinthelateralwallofsinus)-supplieslateralwallandsinusmembrane 1. Posteriorsuperioralveolarartery 2. Infraorbitalartery• Extraosseousanastomosis(withinperiosteum)-suppliessinusmucousmembranes 1. Posteriorsuperioralveolarartery 2. Infraorbitalartery• Posteriorlateralnasalartery(medialandposteriorwall)-suppliesmedialandposteriorwallsofmaxillarysinus • BOX 37.1 Arterial Supply to Posterior Maxilla (Double Arterial Arcade) 995CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryVariouselementsmaydecreasethe numberofcilia andslowtheirbeatingeciency.Viralinfections,pollution, allergicreac-tions, and certain medications may aect the cilia in this way. Genetic disorders (e.g., dyskinetic cilia syndrome) and factorssuch as long-standing dehydration, anticholinergic medications and antihistamines, cigarette smoke, and chemical toxins also can aect ciliary action23(Fig.37.8).An alteration in the sinus ostium patency or the qualityof secretions can lead to disruption in ciliary action, which may result in rhinosinusitis. For clearance to be maintained, adequateventilationisnecessary.Ventilationanddrainagearedependent on the ostiomeatal unit, which is the main sinus opening.Ciliarymovementsofciliatedepithelialcellsdictateclearance of the maxillarysinus. Itis important to maintainthe patency of the maxillary ostium and the ostiomeatal com-plexinthepostoperativeperiodtominimizethepossibilityofcomplications.e physiologic mucociliary transport system may be com-promised by abnormalities in the cilia, which include a decrease in overall ciliary number and poor coordination of their move-ment. is altered physiology may result in an increased mor-bidity of implant placement or bone graft healing. erefore it is crucial that the mucociliary drainage mechanism be main-tained throughout the postoperative treatment period. is is most likely accomplished with good surgical technique, evaluation and treatment of prior drainage issues, and strict adherencetotheuseofpharmacologicagents(e.g.,antibiotics,corticosteroids). Organisms trapped on mucus Mucus movementOstiumOuter layerof mucusPericiliaryserous fluidPseudostratifiedcolumnarepithelial cellMucous glandCiliaGoblet cellBasal cellAirGel phasePropulsionAqueous phaseRecoveryEpitheliumABCD• Fig. . Maxillary sinus membrane (Schneiderian Membrane). (A) The pseudostratified columnar epi-thelium cells have 50 to 200 cilia per cell that beat toward the ostium to help clear 1 L of mucus from goblet and mucous glands each day from the sinus. In health, the mucous has two layers: a bottom serous layer and top mucoid layer. The cilia beat with a stiff stroke in the mucoid layer toward the ostium and a relaxed recovery stroke within the serous layer. (B) Cross-sectional image depicting an inflamed Schnei-derian membrane. If the sinus membrane is of normal thickness, it will not be visible on a radiograph. (C) Clinical image depicting the thinness of the lateral wall and show through (dark blue) of the Schneiderian membrane. (D) Bluish hue of the membrane after lateral wall window preparation. 996PART VII Soft and Hard Tissue RehabilitationMaxillary Sinus Bacterial Floraereismuchdebateonthebacterialoraofthemaxillarysinus.Maxillary sinuses have been considered to be generally sterile in health;however, bacteria can colonizewithin the sinus withoutproducingsymptoms.Intheory,themechanismbywhichaster-ile environment is maintained includes the mucociliary clearance system, immune system, and the production of nitric oxide within thesinuscavity.Inrecentendoscopicstudies,normalsinuseswereshowntobenonsterile,with62.3%exhibitingbacterialcoloniza-tion. e most common bacteria cultured were Streptococcus viri-dans, Staphylococcus epidermidis, and S. pneumoniae.24 e culture ndings for secretions in acute maxillary sinusitis yielded high numbers of leukocytes, S. pneumoniae, or S. pyogenes, with Hae-mophilus inuenzae being recovered from the purulent exudates with lower numbers of staphylococci. Other reports have indicated thebacterialoraofthemaxillarysinusconsistsofnonhemolyticand alpha hemolytic streptococci, as well as Neisseriaspp.Addi-tional microorganisms identiable in various quantities belong to staphylococci, Haemophilus spp., pneumococci, Mycoplasma spp., and Bacteroides spp. is is important to note because the sinus graft procedure often violates the sinus mucosa, and bacteria may contaminate the graft site, leading to postoperative complications.e implant clinician must understand the importance of reduc-ing the bacterial count and possible microorganisms that may initiate infectionsinthemaxillarysinus.Astrictaseptictechniqueshouldbeadhered to during any surgical procedures that invade the maxillary sinusproper.iswillminimizethepossibilityofbacterialcoloniza-tion within the graft, which may lead to increased morbidity. e type of bacteria inhabiting the sinus is very important because it dictates what antibiotic is prescribed preoperatively, postoperatively, and therapeutically in case of infection. e most common bacteria present in the sinus must be susceptible to the specic antibiotic to prevent infection and decrease the morbidity of the graft. e antibi-oticselectedshouldnotbetheclinician’s“favorite”;insteaditshouldbe the most ideal antibiotic, which is specic for the involved bac-teria.Ideally,Augmentin(875/125mg)hasbeenshowntobemosteective antibiotic for bacterial infections in the maxillary sinus. Maxillary Sinus: Clinical AssessmentTo establish adequate osseous morphology for the placement of endosteal implants in the resorbed maxillary posterior region, various grafting techniques have been developed to increase bone volume.In1987Misch25 developed four dierent categories for thetreatmentoftheposteriormaxilla(termedsubantral[SA])asSA-1throughSA-4andwaslatermodiedandupdatedbyResnikin2017(Fig.37.9). eSA-1posteriormaxilla allowsimplantplacement inferior to the sinus cavity, without penetration into ABCD• Fig. . Subantral augmentation classification. (A) SA-1: implant placement that does not extend into the maxillary sinus proper. (B) SA-2: implant placement that elevates the sinus membrane approximately 1 to 2 mm without bone grafting. (C) SA-3: implant placement and simultaneous bone grafting by either a crestal or lateral-wall approach. (D) SA-4: lateral wall sinus augmentation with delayed implant placement. 997CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerythesinusproper.Becausethesinusoorisnotaltered,apreexist-ing sinus pathology or anatomic variant will be less likely to aect thehealingprocess.Assuch,ifthepatienthasapreexistingmaxil-lary sinus condition or develops a sinus infection after implant placement, then implants are not at risk of becoming contami-nated.However,theSA-2toSA-4surgicalproceduresdoalterthesinusmembrane andsinus oor.Withthesetreatmentoptions,a thorough preoperative evaluation is completed to rule out any existingpathologicconditioninthemaxillarysinus.Inthisway,the risk of possible mucus or bacteria contaminating the graft and creating a bacterial smear layer on the implant is reduced. ere-fore the possibility of impaired bone formation during healing is reduced.Inaddition, becauseof theproximityofthe maxillarysinus to numerous vital structures, postoperative complications can be very severe and even life-threatening.Pathologicconditionsassociatedwiththeparanasalsinusesarecommonailmentsandaictmorethan31millionpeopleeachyear.Approximately16millionpeoplewillseekmedicalassistancerelated to sinusitis; yet sinusitis is one of the most commonlyoverlookeddiseasesinclinicalpractice.Potentialinfectionintheregionofthesinusesmayresultinseverecomplications.Infectionsin this area have been reported to result in sinusitis, orbital celluli-tis,meningitis,osteomyelitis,andcavernoussinusthrombosis.Infact,paranasalsinusinfectionaccountsforapproximately5%to10%ofallbrainabscessesreportedeachyear.26A physical examination of the maxillary sinus evaluates themiddle third of the face for the presence of asymmetry, deformity, swelling, erythema, ecchymosis, hematoma, or facial tenderness (Table37.1).Nasalcongestionorobstruction,prevalentnasaldis-charge,epistaxis(bleedingfromthenose),anosmia(thelossofthesenseofsmell),and/orhalitosis(badbreath)arenoted.e clinical examination for maxillary rhinosinusitis concerns the regions surrounding the maxillary antrum. e examination is con-ducted to assess each wall surrounding the maxillary sinus separately. e infraorbital foramen on the facial wall of the antrum is palpated through the soft tissue of the cheeks or intraorally to determine whether tenderness or discomfort is present. e intraoral examination assesses theooroftheantrumbyalveolarulceration,expansion,tenderness,paresthesia, and oroantral stulae. e eyes are examined to evaluate the superior wall of the sinus for proptosis, pupillary level, lack of eye movement,anddiplopia.enasaluidsmaybeusedtoevaluatethemedial wall of the sinus by asking the patient to blow the nose in a waxedpaper.emucusshouldbeclearandthininnature.Ayellowor greenishtintor thickened discharge indicates infection. Infectedmaxillary sinuses typically are symptomatic, which can exhibit exudate in the middle meatus and may be inspected with a nasal speculum andheadlight(rhinoscopy)throughthenares.emethodsofexami-nation of the infected maxillary sinus may include transillumination, nasoendoscopy, bacteriology, cytology, beroptic antroscopy, and radi-ographyCBCT,ormagneticresonanceimaging[MRI]). Maxillary Sinus Radiographic EvaluationVariousradiographictechniqueshavebeenusedinimplantdentistrytoevaluatethemaxillaryposteriorregion.Intheearlydaysoforalimplantology, evaluation of this area was limited to 2-dimensional (2D)radiographs.However,thesetypesofradiographshaveinher-ent disadvantages that are aected by magnication and distortion, whichleadstoerrorsindiagnosisandtreatmentplanning.Currently,thisanatomicareaisevaluatedmainlybytheuseof3Dradiographictechniques(CBCT)ormedicalCTbecausetheyhavebecomemoreaccurateandecient,withasignicantreducedradiation.Cone Beam Computerized TomographyCBCT surveyshave allowedthe implant clinician to evaluateanatomic structures, anatomic variants, and pathologies more accurately. Many software programs are available that allow combining 3D images with computer software and allow anaccurateassessmentofthemaxillarysinus.Becausevisualizationof the maxillary sinus and surrounding structures are crucial for the proper diagnosis and treatment planning, it is highly sug-gestedtheimplantclinicianutilizeCBCTanytimeproceduresinvolve the maxillary sinus.Presently,noradiographicmodalityprovidesmoreinformationabouttheparanasalsinusesthanCBCT.istypeofradiographyprovides much more detailed information about the anatomy and pathologic condition of the sinuses compared with 2D radiog-raphy.StudieshaveconcludedthatCBCTisthebestoptionforviewing the surrounding osseous structures and pathologic condi-tion in the maxillary sinuses.27,28e maxillary sinus can be evaluated with most CBCT images,including reformatted axial, panoramic, cross-sectional, sagittal, and 3Dimages.Mostphysiciansusethecoronalradiographstoevaluatetheparanasal sinuses. e implant clinician must have a clear understand-ingoftheCBCTradiographicanatomyandthepathologicconditionsassociated with the posterior maxilla and maxillary sinus regions. Normal AnatomyMaxillary Sinus Membrane (Schneiderian Membrane)ACBCTscanofnormal,healthyparanasalsinusesrevealsacom-pletelyradiolucent(dark)maxillarysinus.Anyradiopaque(whit-ish) area within the sinus cavity is abnormal, and a pathologiccondition should be suspected. e normal sinus membrane is radiographicallyinvisible,whereasanyinammationorthicken-ing of this structure will be radiopaque. e density of the dis-easedtissueoruidaccumulationwillbeproportionaltovaryingdegrees of gray values.  Preoperative and Postoperative Physical ExaminationSite Signs of InfectionInferior wall Bulgeinhardpalate,ill-ttingden-ture,looseteeth,hypesthesiaornonvitalteeth,bleeding,palatalerosion,oroantralstulaMedial wall Nasalobstruction,nasaldischarge,epistaxis,cacosmia,visiblemassinnostrilAnterior wall Swelling,pain,skinchangesPosterior wall Midfacepain,hypesthesiaofone-halfofface,lossoffunctionoflowercranialnervesSuperior wall Diplopia(doublevision),proptosis(eyebulgingout),chemosis,painorhypesthesia,decreasedvisualacuity TABLE 37.1 998PART VII Soft and Hard Tissue RehabilitationOstiomeatal Complexe ostiomeatal unit is composed of the maxillary ostium, eth-moid infundibulum, anterior ethmoid cells, and the frontal recess. e main drainage avenue of the maxillary sinus is through the ostium. e maxillary ostium is bounded superiorly by the eth-moid sinuses and inferiorly by the uncinate process. e uncinate process is a bony knifelike projection that is attached inferiorly to theinferiorturbinateandposteriorlyhasafreemargin.Drainagecontinues through the ostium into the infundibulum, which is a narrow passageway leading into the middle meatus. e middle meatus is the radiolucent space bounded by the middle and infe-rior turbinates. Nasal CavityWithinthenasalcavity,threenasalturbinatesorconchae(supe-rior,middle,andinferior)existandaresmalldownwardprojec-tions of bone. Between the turbinates is a space or recess termed a meatus. e respiratory epithelium covers the turbinates and meatus and warms, moistens, and cleans the air that is respirated into the lungs.e nasal septum is the bony partition that creates a barrier between the right and left sides of the nasal cavity. Obstructions within any aspect of the nasal system predispose the area to patho-logicconditions(Fig.37.10). Maxillary Sinus: Anatomical VariantsNumerous anatomic variants arise that can predispose a patient topostsurgicalcomplications.Whentheseconditionsarenoted,apharmacologicprotocolmayneedtobealteredand/orimplantsmay be placed after the sinus graft has matured, rather than pre-disposing them to an increased risk by inserting them at the same timeasthesinusgraft.Asstatedpreviously,patencyoftheostiumisparamounttomaintaindrainage.Preexistingskeletalandbonyabnormalities of the ostiomeatal complex may compromise the patency of the maxillary ostium, thereby, predisposing patients to maxillary rhinosinusitis.Paradoxical middle turbinateDeflecteducinateprocessPolypsNon-patentostiumMucousretention cystBig nosevariantDeviatedseptumConchabullosaHiatusSemilunarisInfundibulumOsteomeatalcomplexUncinateprocessMiddlemeatusMaxillarysinusOstiumMaxillarysinusMiddle turbinate Inferior meatusInferior turbinate Nasal septumEyeEthmoidsinusEthmoidbullaFrontalsinusAB• Fig. . (A) Normal paranasal anatomy. (B) Paranasal pathology and anatomic variants. 999CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryNasal Septum DeviationAnasalseptumdeviationisaverycommonanatomicvariant,occur-ringinasmuchas70%ofthepopulationolderthan14years.isbony variant in extremes may cause obstruction of the ostiomeatal unit, which resultsininammationfromairturbulence,causingincreasedmucosaldryingandparticledeposition.Ifthedeviationis long-standing, then atrophy of the middle turbinate may occur, resultinginnarrowingoftheostiomeatalcomplex(Fig.37.11).29Timmenga and colleagues30evaluated45patientswhoreceived85sinusgraftswithendoscopypostsurgery. Ofthe45patients,ve were found to have sinusitis postsurgery; all ve of thosepatients had a nasal deviation or oversized turbinate. ereforewhen these conditions are observed, consideration should be given to not place the implant at the same time as the sinus graft, and the recommended preoperative and postoperative pharmacologic protocol is especially warranted. Middle Turbinate Variantse middle turbinate plays a signicant role in proper drainage of themaxillarysinus.Aconchabullosaisapneumatizationwithinthe middle turbinate and may occlude the ostiomeatal complex, compromising adequate drainage. is variant is seen in approxi-mately4%to15%ofthepopulation(Fig.37.12).31Anothervari-ant in this anatomic structure is a paradoxically curved middle turbinate, which presents a concavity toward the septum, decreas-ingthesizeofthemeatus.isalsopredisposesthepatienttoahigher incidence of sinus disease. Uncinate Process Variantse uncinate process is a projection of the ethmoid bone which is located in the wall of the lateral nasal cavity. is bony process is an importantanatomicstructureinthepatencyoftheostium.Adeecteduncinateprocess(eitherlaterallyormedially)cannarrowtheethmoidinfundibulum, aecting the ostiomeatal complex. Perforations mayalso be present within the uncinate process, leading to communication betweenthenasalcavityandethmoidinfundibulum.Inaddition,theuncinateprocessmaybepneumatized.Althoughthisisrare,itmaycompromise adequate clearance and drainage of the maxillary sinus. Supplemental OstiaAsupplementalostiumorsecondaryostiamayoccurbetweenthemaxillary sinus and the middle meatus, which is often found in theposteriorfontanelles(PF).ismaybefoundinapproximately18%to30%ofindividuals.Becausethesesecondaryopeningsareusually located posterior and inferior to the natural ostium, they may predispose the patient to sinusitis by the recirculation of infected secretions from the primary meatus back into the sinus cav-ity. On occasion, these secondary ostia may be encountered during the elevation of the medial wall of the antrum before placement of thesinusgraft.Whenobserved,apieceofcollagenisplacedoverthesite to prevent graft material from entering the nasal cavity. Maxillary HypoplasiaHypoplasia of the maxillary sinus may be a direct result from trauma, infection, surgical intervention, or irradiation to the max-illa during the development of the maxillary bone. ese condi-tions interrupt the maxillary growth center, producing a smaller than normal maxilla. A malformed and positioned uncinateprocess is associated with this disorder, leading to chronic sinus drainage problems. Most often, these patients have adequate bone • Fig. . Nasal septum deviation is a common variant. Extreme cases may obstruct the ostiomeatal unit and increase the risk of sinusitis after a sinus graft.MTITAB• Fig. . (A) Nasal cavity anatomy: inferior turbinate (IT), middle turbi-nate (MT), inferior meatus (red arrow), middle meatus (yellow arrow). Note the paradoxical middle turbinate. (B) Coronal image depicting concha bul-losa (arrow) and deviated septum. 1000PART VII Soft and Hard Tissue Rehabilitationheight for endosteal implant placement, and a sinus graft is not requiredtogainverticalheight(Fig.37.13)Inferior Turbinate and Meatus Pneumatization (Big-Nose Variant)Misch had observed, on rare occasion, that the inferior third of the nasal cavity pneumatizes within the maxilla and resides overthe alveolar residual ridge. An evaluation of 550 computerizedtomography(CT)scansofcompleteorpartiallyedentulousmaxil-laefoundthisconditionin18patients(3%incidence).Whenthepatient has this condition, the maxillary sinus is lateral to the eden-tulousridge.When inadequateboneheight ispresentbelowthisstructure, a sinus graft does not increase available bone height for an implant.isconditionisdiculttoobserveonatwo-dimensionalpanoramicradiograph.Ifunaware,thentheimplantcanbeplacedinto the nasal cavity above the residual ridge and even penetrate the inferiorturbinate.Asinusgraftiscontraindicatedwiththispatientcondition because the sinus is lateral to the position of the implants. Instead,inmostcasesanonlaygraftisrequiredtoincreaseboneheight(Fig.37.14). Maxillary Sinus PathologyApre-existing,pathologic,maxillarysinusconditionmaybearela-tive or absolute contraindication for many procedures that will alter thesinusoorbeforeorinconjunctionwithsinusgraftingand/orimplant insertion. e risk of postoperative infection is elevated and may compromise the health of the implant and the patient. ere-fore pathologic conditions, either preoperative or postoperative, of a maxillary sinus should be evaluated, diagnosed, and treated.Pathologic conditions of the maxillary sinus may be dividedinto four categories: (1) inammatory lesions, (2) cystic lesions,(3)neoplasms,and(4)antrolithsandforeignbodies.Studieshaveshownthat20%to45%oftheasymptomaticpopulationhasasub-clinical pathologic condition in the maxillary sinus. e author has evaluatedapproximately2000prospectivecandidatesformaxillarysinusaugmentationproceduresattheMischInternationalImplantInstitute for signs of pathology. e results concluded 38.7% ofasymptomatic patients had maxillary sinus pathologic conditions on CBCT scan evaluation. Manji and colleagues evaluated 275patients and concluded that 45.1% were classied as exhibitingsinus pathology (i.e., 56.5% had mucosal thickening (≥5 mm),28.2%withpolypoidalthickening,8.9%partialopacicationand/orair/uidlevel,and6.5%completeopacication).32 Because of this increased incidence, it is highly recommended that a thorough radiographic evaluation be completed on all prospective sinus eleva-tion patients.Inflammatory DiseaseInammatory conditions can aect the maxillary sinus fromodontogenic and nonodontogenic causes.Odontogenic Rhinosinusitis (Periapical Mucositis)Odontogenic sinusitis describes a type of sinus disease in which radiographic,microbiologic,and/orclinicalevidenceindicatesitisofadentalorigin(i.e.,fromatooth).ecloseproximityoftherootsofthemaxillaryposteriorteethtotheoorofthesinussuggestanyinammatorychangesintheperiodontiumorsurroundingalveolarbone may result in pathologic conditions in the maxillary sinus.Etiology. Odontogenic sinusitis is usually the result of an infectedtooth(e.g.,periapicalabscess,cyst,granuloma,periodontaldisease)thatcausesanexpansilelesionwithintheoorofthesinus.Periapicalinammation has beenshownto becapableofaect-ing the sinus mucosa, with and without perforation of the cortical boneofthesinusoor.Infectionandinammatorymediatorsarecapable of spreading directly or via bone marrow, blood vessels, and lymphatics to the maxillary sinus, causing an inammatoryresponse.33Additionaletiologicfactorsincludesinusperforationsduringextractionsandforeignbodies(e.g.,gutta-percha,roottips,amalgam).Odontogenicrhinosinusitisisoftenpolymicrobial,withanaerobic streptococci, Bacteroides spp., Proteus spp., and coliform bacilliinvolved.Studieshaveshown10%to40%ofallrhinosinus-itis sinusitis cases may have an underlying dental pathology.34,35 Radiographic Appearance. e radiographic evaluation of patients with odontogenic sinusitis will most commonly dem-onstrate a unilateral maxillary sinusitis. A unilateral maxillaryodontogenicsinusitisisoftenoverlookedonCBCTscansbecausetheyarefrequently asymptomatic. Involvementof the ostiome-atal complex may result in extension to adjacent paranasal sinuses (e.g., ethmoid, frontal, sphenoid), ranging from 27% to 60%among patients with odontogenic sinusitis.36 Odontogenic sinus-itishas been shownto exhibit bilateralinvolvementin 20% of• Fig. . Inferior meatus pneumatization (big nose variant). Cone beam computerized tomographic panoramic image depicting the abnormally large nasal cavity extending into the molar area.• Fig. . Maxillary hypoplasia. Coronal cone beam computerized tomographic view of an abnormally small sized maxillary sinus 1001CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerypatients.Insomecases,aslightthickeningofthesinusmembranemay be present adjacent to the oending tooth.37 Usually the radiographic appearance will be a radiopaque band that follows thecontoursofthesinusoor. Dierential Diagnosis. Odontogenic sinusitis may be confused withacuterhinosinusitissinusitis;however,acuterhinosinusitisisalmost always symptomatic. Mild mucosal thickening from a non-odontogenicorigin(e.g.,smoking,allergy)mayalsoshowsimilarradiographic signs. However, the nonodontogenic origin may be conrmed from lack of radiographic evidence of a diseased or pain-ful tooth. Treatment. Before any type of sinus augmentation or implant placement into the sinus, the tooth or teeth involved should be treatedperiodontally,endodontically,orextracted.Afterintraoralsofttissuehealingandresolutionofthepathologiccondition(i.e.,aminimumof6weeks),thebonegraftand/orimplantmaybeperformed with minimal morbidity. e removal of unhealthy teeth decreases sinus membrane thickening, but most of the time itdoesnotcompletelyresolveit.Inaddition,epithelialmetaplasiawith the ciliated mucosa changing to simple cuboidal and strati-edsquamouskeratinizedtissuemayresult.erefore,depend-ing on the severity, in some cases the mucosal thickness may remain because of the change in epithelia structure and metaplasia changes6(Fig.37.15). Mild Mucosal Thickening (Nonodontogenic)Sinus membrane thickening has been shown to be present in approximately46.7%ofpatients,withequaldistributionbetweenhealthy and unhealthy natural teeth.38 e most common area for the mucosal thickening has been shown to be in the midsagittal sinusregion,whichisadjacenttotherstandsecondmolars.Inthe literature, it is accepted that mucosal thickening greater than 2 mm is considered a pathologic sinus membrane.39-42Etiology. Local odontogenic issues, such as periapical pathol-ogy, periodontal disease, and the health of the adjacent dentition, havebeenshowntobetheetiologicfactorintheinammatoryresponsetothesinusmembraneinapproximately50%ofcases.43 However, nonodontogenic factors such as smoking,44 allergies, sinus congestion, mold, and air pollution may aggravate the sinus mucosa,resultinginmildthickening.Chronicinammatorycon-ditionsmayresultinalteredbacterialora,alongwithmucociliaryclearance and cilia changes. Radiographic Appearance. OnaCBCTimage,usuallythick-ened mucosa will appear as a radiopaque widened membrane. ickened mucosa can easily be seen when evaluating axial images. Treatment. Usually no treatment is necessary because mild mucosal thickening is asymptomatic. Studies have shown that slight mucosal thickening allows for sinus grafting procedures to be completed with a decreased incidence of membrane perfora-tion(Fig.37.16). Acute RhinosinusitisAnonodontogenicpathologicconditionmayalsoresultininam-mation in the form of sinusitis. e most common type of sinus-itis is acute rhinosinusitis (i.e., sinusitis symptoms of less than3months).e signs and symptomsofacuterhinosinusitis arerather nonspecic, making it dicult to dierentiate from thecommoncold,inuenzatypeofsymptoms,andallergicrhinitis.However, the most common symptoms include purulent nasal discharge, facial pain and tenderness, nasal congestion, and pos-sible fever.Acute maxillary rhinosinusitis results in 22 to 25 millionpatient visits to a physician in the United States each year, with a direct or indirect cost of $6 billion. Although four paranasalsinuses exist in the skull, the most common involved in rhinosi-nusitis are the maxillary and frontal sinuses.45Etiology. An inammatory process that extends from thenasal cavity after a viral upper respiratory infection often causes acute maxillary sinusitis. Microbiological cultures have shown the most common pathogens causing acute rhinosinusitis are S. pneu-moniae, H. inuenzae, and Moraxella catarrhalis. ese pathogens includeapproximately20%to27%β-lactamase–resistantbacte-ria. S. aureus has also been cited, with the microbiology of acute rhinosinusitis. However, this pathogen is usually only seen in nos-ocomial(hospital-induced)sinusitisandisunlikelytobeseeninan elective sinus graft patient.e most important factor in the pathogenesis of acute rhinosi-nusitis is the patency of the maxillary ostium.46,47 Local predispos-ingcausesofsinusitisincludeinammationandedemaassociatedwith a viral upper respiratory tract infection or allergic rhinitis. As a consequence, mucous production within the sinus maybe abnormal in quality or quantity, along with a compromised • Fig. . Odontogenic rhinosinusitis. Cone beam computerized tomo-graphic panoramic view showing molar roots extending into the maxillary sinus, resulting in inflammation of the sinus membrane. Note the com-munication between the maxillary molar roots and the maxillary sinuses.• Fig. . Mild mucosal thickening. Three-dimensional axial view show-ing bilateral mucosal thickening (gray area surrounding the bony walls of the maxillary sinus). 1002PART VII Soft and Hard Tissue Rehabilitationmucociliarytransport.Inanoccludedostium,anaccumulationofinammatorycells,bacteria,andmucusexists.Phagocytosisofthebacteriaisimpairedwithimmunoglobulin(Ig)-dependentactivi-ties decreased by the low concentration of IgA, IgG, and IgMfound in infected secretions.e oxygen tension inside the maxillary sinus has signicant eectsonpathologicconditions.Whentheoxygentensioninthesinus is altered, resultant sinusitis occurs. Growth of anaerobic and facultative organisms proliferate in this environment.48 Many fac-torsmay alterthe normaloxygentensionwithin thesinuses.Adirectcorrelationexistsbetweentheostiumsizeandtheoxygentensioninthesinus.Inpatientswithrecurrentepisodesofsinus-itis, oxygen tension is often reduced, even when infection is not present.Asaconsequence,ahistoryofrecurrentacuterhinosinus-itis is relevant to determine whether a bone graft or dental implant may be at increased risk of morbidity. Radiographic Appearance. e radiographic hallmark in acuterhinosinusitisistheappearanceofanair-uidlevel.Alineofdemarcationwillbepresentbetweentheuidandtheairwithinthemaxillarysinus.Ifthepatientisradiographically positionedsupine,thentheuidwillaccumulateintheposteriorarea;ifthepatientisuprightduringtheimagingsurvey,theuidwillbeseenon the oor and horizontal in nature. Additional radiographicsigns include smooth, thickened mucosa of the sinus, with pos-sibleopacication.Inseverecases,thesinuscavitymayllcom-pletely with supportive exudates, which gives the appearance of a completelyopaciedsinus.Withthesecharacteristics,thetermspyocele and empyema have been applied. Treatment. Because acute rhinosinusitis is one of the most common health problems today, patients having sinus grafting procedures should be well screened for a past history and cur-rentsymptoms.Eventhoughacuterhinosinusitisisaself-limitingdisease, a symptomatic patient should be treated and cleared by their physician before any grafting procedures. ese patients are alsomorepronetopostoperativerhinosinusitis.Asaresult,asinusgraft is performed and given a longer healing period before place-mentofanimplant.Inaddition,thesuggestedantibioticcoveragemay be altered and extended, both before and after the sinus graft procedure(Fig.37.17). Chronic RhinosinusitisChronicrhinosinusitisisatermusedforasinusitisthatdoesnotresolvein3monthsandalsohasrecurrentepisodes.Itisthemostcommon chronic disease in the United States, aecting approxi-mately 37 million people. Symptoms of chronic rhinosinusitis are associated with periodic episodes of purulent nasal discharge, nasal congestion, and facial pain.Etiology. Asmaxillaryrhinosinusitisprogressesfromtheacutephase to the chronic phase, anaerobic bacteria become the predomi-nant pathogens. e microbiology of chronic rhinosinusitis is very dicultto determinebecause oftheinabilitytoacquireaccuratecultures. Studies have shown that possible bacteria include Bacte-roides spp., anaerobic gram-positive cocci, Fusobacterium spp., and aerobicorganisms (Streptococcus spp., Haemophilus spp., Staphylo-coccusspp.).49AMayoClinicstudyshowedthatin96%ofpatientswith chronic rhinosinusitis, active fungal growth was present.50 Radiographic Appearance. Chronic rhinosinusitis mayappear radiographically as thickened sinus mucosa, complete opacicationoftheantrum,and/orscleroticchangesinthesinuswalls(which givethe appearanceof densercorticalbonein thelateralwalls). Treatment. Medical evaluation and clearance by an experi-encedphysicianinsinuspathology(e.g.,otolaryngologist[ENT])is highly recommended for patients with chronic maxillary rhi-nosinusitis before any sinus grafting, because signicant bacterial resistance and fungal growth is highly probable. Fungal infections areoftendiculttotreatandcontrol,andseriouscomplicationsmayresultinpostoperativesinusgraftpatients.Inmanychronicrhinosinusitis patients, a sterile and nonpathologic sinus is dif-culttoobtain,contraindicating(absolute)sinusgraftingand/orimplants. Allergic RhinosinusitisEtiology. Allergicsinusitisisalocalresponsewithinthemaxil-lary sinus caused by an irritating allergen in the upper respiratory tract. erefore allergens may be a cause of acute or chronic rhi-nosinusitis. is category of sinusitis may be the most common form, with 15% to 56% of patients undergoing endoscopy forsinusitisshowingevidenceofallergy.Allergicrhinosinusitisoftenleadstochronicsinusitisin15%to60%ofpatients.51 e sinus mucosa frequently becomes irregular or lobulated, with resultant polyp formation. Radiographic Appearance. Polypformationrelatedtoallergicsinusitis is usually characterized by multiple, smooth, rounded,radiopaque shadows on the walls of the maxillary sinus. Most commonly, polyps initially are located near the ostium and are easilyobservedonaCBCTscan.Inadvancedcases,ostiumocclu-sion, along with displacement or destruction of the sinus walls, may be present with a radiographic image of a completely opaci-ed sinus. Treatment. Whenpatientshaveahistoryofallergicrhinosinus-itis, special attention must be given to a patent ostium, bacterial resistance,andclosepostoperativesupervision.Polyps,ifenlargedor too numerous, may be required to be removed before the sinus BA• Fig. . Acute rhinosinusitis. (A and B) Flat radiopaque (gray) line within the maxillary sinus, which is termed an air-fluid level and consistent with acute rhinosinusitis. 1003CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerygraft.ismaybeperformedthroughananteriorCaldwell-Lucapproach or by an endoscopic procedure via the maxillary ostium.Allergicsinusitispatientsoftenhaveagreaterriskofcomplica-tions related to an increase in allergen production. Because sinus grafting is an elective procedure, the time of year for the surgery may be altered to decrease the postoperative infection risk. For example,ifhayfeveroragrassallergyisrelatedtothepatient’ssinusitis, then the sinus graft surgery should be performed in the season or seasons that have least risk to aggravate the sinus mucosa (i.e.,winter orfall).Inseverecasesof polyposis,any procedureviolating the sinus proper may be an absolute contraindication (Fig.37.18). Fungal Rhinosinusitis (Eosinophilic Fungal Rhinosinusitis)Granulomatousrhinosinusitis is a veryserious (and often over-looked)disorderwithinthemaxillarysinus.Patientswhoexhibitsigns of fungal rhinosinusitis may indicate an extensive history of antibiotic use, chronic exposure to mold or fungus in the envi-ronment, or history of immunosuppression. Fungal rhinosinusitis has been categorized into ve types: acute necrotizing (fulmi-nant), chronic invasive, chronic granulomatous invasive, fungalhall(sinusmycetoma),andallergic.erstthreetypesareclas-sied as tissue-invasive and the last two are noninvasive fungal rhinosinusitis.52Etiology. Fungal infections are usually caused by aspergillosis, mucormycosis,orhistoplasmosis.Chronicrhinosinusitispatientsshould always be evaluated for granulomatous conditions because a high percentage of fungal growth exists in this patient popula-tion. Of concern in these patients is eosinophils are activated that releasemajorbasicprotein(MBP)intothemucus,whichattacksand destroys the fungus. However, this may result in the mem-brane being irritated and possibly irreversibly damaged, which allows bacteria to proliferate. ree possible clinical signs may dierentiate fungal rhinosinusitis from acute or chronic rhino-sinusitis;however,apositivediagnosisrequiresmycologicalandhistologic studies.531. Noresponsetoantibiotictherapy2. Soft tissue changes in sinus associated with thickened reactive bone,withlocalizedareasofosteomyelitis3. Association of inammatory sinus disease that involves thenasal fossa and facial soft tissue Radiographic Appearance. Granulomatous rhinosinusitis is extremely variable and may appear radiographically as mild thickening(lesscommon)tocompleteopacication(morecom-mon)ofthesinus.emajorityofsinusesshowcompleteopaci-cation with hyperdense areas.54Extensionbeyondthemaxillarysinus to other sinuses is common and expansion and erosion of a sinus wall may be present. Treatment. Patients with a history or current knowledge offungal rhinosinusitis should be referred to their physician or an ENTfortreatmentandsurgicalclearance(i.e.,inmostcasesclear-ance will not be given because fungal rhinosinusitis is rarely cur-able).Treatmentusuallyinvolvesdebridementandtherapywithanantifungalagent,suchasamphotericinB(Fig.37.19). Cystic LesionsCystic type lesions are a common occurrence in the maxillarysinus. ey may vary from microscopic lesions to large, destruc-tive,expansilepathologicconditions.Cysticlesionsmayincludepseudocysts, retention cysts, primary mucoceles, and postopera-tive maxillary cysts.Pseudocysts (Mucous Retention Cyst)e most common cysts in the maxillary sinus are mucous reten-tion cysts. After much controversy, in 1984, Gardner55 distin-guishedthesecystsintotwocategories:(1)pseudocystsand(2)A B• Fig. . Allergic rhinosinusitis. (A) Bilateral polypoid inflammation consistent with allergic rhinosinusitis. (B) Polyp removal on a patient with chronic allergic rhinosinusitis. Unfortunately the polyps have a high incidence of recurrence, and in many cases this contradicts implant treatment.• Fig. . Fungal rhinosinusitis. Coronal cone beam computerized tomographic image of fungal rhinosinusitis, which has the radiographic appearance of an opacified sinus with localized highly densified areas. 1004PART VII Soft and Hard Tissue Rehabilitationretention cysts. Pseudocysts are more common and of muchgreater concern during sinus graft surgery, compared with reten-tion cysts. Pseudocystsrecur in approximately 30% of patientsand are often unassociated with sinus symptoms. As a conse-quence, many physicians do not treat this condition. However, when their size is larger (approximately >10 mm in diameter),pseudocysts may occlude the maxillary ostium during a sinus graft procedure and increase the risk of postoperative infections. Stud-ies have shown successful bone graft and implant placement in maxillary sinuses with pseudocysts.56EtiologyApseudocystiscausedbyanaccumulationofuidbeneaththeperi-osteum of the sinus mucosa. is elevates the mucosa away from the oorofthesinus,givingrisetoadome-shapedlesion.Pseudocystshave also been termed mucosal cysts, serous cysts, and nonsecreting cysts.Pseudocystsarenottruecystsbecausetheylackanepitheliallining;however,theyaresurroundedbybrousconnectivetissue.57 ecauseoftheuidisthoughttoresultfromsinusmucosabacte-rialtoxinsorfromodontogeniccauses(Fig.37.20). Radiographic AppearancePseudocysts are depicted radiographically as smooth, homog-enous, dome-shaped, round to ovoid, well-dened radiopaci-ties.Pseudocystsdonothaveacorticated(radiopaque)marginalperimeterandalmostalwayslocatedontheoorofthesinuscav-ity.Insomecases,pseudocystsmayencompasstheentiremaxillarysinus,makingdiagnosisdicultbecauseitmayberadiographi-cally similar to rhinosinusitis. TreatmentPseudocystsarenotacontraindicationforsinusgraftsurgery,unlesstheir approximate size increases the possibility of occluding themaxillaryostium.Ifalargepseudocyst(i.e.,greaterthan8mm)ispresent, then the elevation of the membrane during a sinus graft mayraisethecysttooccludetheostium.Inaddition,onelevationor placement of the grafting material, the cyst may be perforated, allowinguidwithinthecysttocontaminatethegraft.Largecystsof this nature should be drained and allowed to heal before or in conjunctionwithsinuselevationsurgery.Mostoften,anENTphy-sicianshouldevaluatetodetermineanyintervention.Ifapseudo-cystislessthan8mm,thenlessconcernisneededandtheuidmay be drained in conjunction with sinus grafting, depending on thesurgeon’sexperienceinthetreatmentofthiscondition.Cautionshouldbeexercisedtopreventmembraneperforation.Astrictrecallevaluation of this area during the follow-up period of the sinus graft surgery is in order because reoccurrence of pseudocysts is common. Retention CystsRetentioncystsmaybelocatedonthesinusoor,neartheostium,or within antral polyps. Because they contain an epithelial lining, researchersconsiderthemtobemucoussecretorycystsand“true”cysts.Retentioncystsareoftenmicroscopicinsize.EtiologyRetention cysts result from partial blockage of seromucinousgland ducts located within the connective tissue underlying the sinusepithelium.Asthesecretionscollect,theyexpandtheduct,producing a cyst that is encompassed by respiratory or cuboidal epithelium. ey may be caused by sinus infections, allergies, or odontogenic reasons. Radiographic AppearanceRetentioncystsareusuallyverysmallandnotseenclinicallyorradiographically.Inrareinstances,theymayachieveadequatesizetobeseeninaCTimageandmayresembletheappearanceofasmall pseudocyst. TreatmentNo treatment for retention cysts exist before or in conjunction withasinusgraftand/orimplantinsertion. FluidAB• Fig. . Pseudocyst. (A) Diagram showing fluid accumulation underneath the membrane. (B) Radio-graph showing the dome-shaped characteristics of a pseudocyst. 1005CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryPrimary Maxillary Sinus MucoceleAprimarymucoceleisacystic,expansile,destructivelesionthatmay include painful swelling of the cheek, displacement of teeth, nasal obstruction, and possible ocular symptoms.58 e primary mucoceleismorecommonlyfoundintheethmoidsinus(45.5%)versusthemaxillarysinus(18.3%).59Etiologye primary mucocele arises from blockage of the maxillary ostium by brous connective tissue. Because of the compromised drainage, the mucosa expands and herniates through the antral walls. is mucocele is classied as a cyst because it is lined by antral epithelium, which contains mucin. Radiographic AppearanceIntheearlystages,theprimarymucoceleinvolvestheentiresinusandappearsasanopaciedsinus.Asthecystenlarges,thewallsbecomethinandeventuallyperforate.Inthelatestages,destruc-tion of one or more surrounding sinus walls is evident. TreatmentSurgical removal of this cyst is indicated prior to any bone aug-mentationprocedures(Fig.37.21). Secondary Maxillary Sinus Mucocele (Postoperative Maxillary Cyst)A postoperative maxillary cyst of the maxillarysinus is a cysticlesion that usually develops secondary to a previous trauma or surgicalprocedureinthesinuscavity.Italsohasbeentermedasurgical ciliated cyst, postoperative maxillary sinus mucocele, or a secondary mucocele.60-62 Secondary mucoceles occur most commonlyinthemaxillarysinus(86%)versustheethmoidsinus(7.1%).59EtiologyApostoperativemaxillarycystisadirectresultoftraumaorpasthistory of surgery within the maxillary sinus. e cyst is derived from the antral epithelium and mucosal remnants that previ-ously were entrapped within the prior surgical site. is separated mucosa results in an epithelium-lined cavity in which mucin is secreted. e antrum becomes divided by a brous septum in which one part drains normally, whereas the other part is com-posedofthemucocele.ItisrelativelyrareintheUnitedStates;however,itconstitutesapproximately24%ofallcystsinJapan.Atleastthreereportedcasesexistofapostoperativemaxillarycystforming after a sinus graft procedure, including one by the author of this chapter.63 Radiographic Appearancee cyst radiographically presents as a well-dened radiolucency circumscribed by sclerosis. e lesion is usually spherical in the earlystages,withnobonedestruction.Asitprogresses,thesinuswallbecomesthinandeventuallyperforates.Inlaterstages,itwillappear as two separated anatomic compartments. TreatmentSurgical ciliated cysts should be enucleated before any bone aug-mentationprocedures.Ifobservedafterthesinusgraft,thenthecystsshouldbeenucleatedandregraftedinthesite(Fig. 37.22) NeoplasmsEtiologyPrimarymalignanttumorswithinthemaxillarysinusareusuallycaused by squamous cell carcinomas or adenocarcinomas. Signs and symptoms of malignant disease are related to the surround-ing sinus wall that the tumor invades and includes swelling in the cheek area, pain, anesthesia or paresthesia of the infraorbital nerve (e.g.,anteriorwall),andvisualdisturbances(e.g.,superiorwall).ese tumors in the sinus are usually nonspecic and give a variety FluidAB• Fig. . Primary maxillary sinus mucocele. (A) Diagram showing expansive nature of a primary maxil-lary sinus mucocele. (B) Radiograph showing the initial stage of complete opacification and later stages including expansion of the bony plates. 1006PART VII Soft and Hard Tissue Rehabilitationofconsequences,includingopaciedsinuses;softtissuemassesinthesinus;andsclerosis,erosion,ordestructionofthewallsofthesinus. Sixty percent of squamous cell carcinomas of the parana-sal sinuses are located in the maxillary sinus, usually in the lower one-halfoftheantrum.Clinicalsignsintheoralcavityreecttheexpansion of the tumor and an increased mobility of the involved teeth.Invasionoftheinfratemporalfossaisalsopossible.1 Radiographic AppearanceRadiographicsignsofneoplasmsmayincludevarious-sizedradi-opaquemasses,completeopacication,orbonywallchanges.Alack of a posterior wall on a panoramic radiograph should be a signofpossibleneoplasm(Fig. 37.23). TreatmentAnysignsorsymptomsofalesionofthistypeshouldbeimmedi-ately referred for medical consultation. Sinus graft surgery is abso-lutely contraindicated while this condition exists. Antroliths and Foreign BodiesMaxillary sinus antroliths are the result of complete or partial encrustation of a foreign body. ese masses found within the maxillary sinus originate from a central nidus, which can be endogenous or exogenous.64Etiologye majority of endogenous sources are from dental origin, including retained roots, root canal sealer, fractured dental instru-ments,anddentalimplants. Additionally, bone spicules,blood,and mucus have been reported to cause antroliths.65Reportsinthe literature of exogenous sources include paper, cigarettes, snu, and glue.66 Although most antroliths are asymptomatic, theyoften are associated with sinusitis. Radiographic Appearancee radiographic appearance of a maxillary antrolith resembles eitherthecentralnidus(e.g.,retainedroot)orappearsasaradi-opaque,calciedmasswithinthemaxillarysinus(Fig.37.24). Differential DiagnosisBecause the calcied antrolith is composed of calcium phosphate (CaPO4),calciumcarbonatesalts,water,andorganicmaterial,itwillbe considerably moreradiopaque than an inammatory orcystic lesion.67 e central nidus of the antrolith is similar to its usual radiographic appearance. FluidBAC D• Fig. . Secondary maxillary sinus mucocele. (A) Diagram showing cystic nature of a secondary mucocele, which divides the sinus into two compartments. (B) Radiograph of blade implant with well-defined radiolucency around the implant. (C) Blade implant removed with associated pathology. (D) Histol-ogy revealing a secondary maxillary sinus mucocele. 1007CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryTreatmentBefore sinus augmentation and implant placement, the antrolith shouldbesurgicallyremoved.Ifsinusitisexists,thenthesinuscav-ity should be allowed to heal completely before sinus augmen-tation procedures. A nonsymptomatic condition may have theantrolith removed and sinus graft performed at the same surgery, only if the sinus membrane is not compromised. Miscellaneous Factors That Affect the Health of the Maxillary SinusSmokinge use of tobacco is one of the main factors that may lead to an increased morbidity after sinus graft procedures. Smoking is known to be associated with an increased susceptibility to aller-gies and infections because it interferes with ciliary function and secretoryimmunityofthenasorespiratorytract.Inthemaxillarysinus, this may have direct eects on both immune exclusion and suppressionbecauseIgAandIgMresponsesarereduced,whereasIgE responses are increased. Smoking is believed to interferewith bone graft healing because it reduces local blood ow byincreasing peripheral resistance and causing an increased platelet aggregation. By-product chemicals of smoking, such as hydrogen cyanide and carbon monoxide, have been shown to inhibit wound healing, as does nicotine, which inhibits cellular proliferation. Tobacco may interfere directly with osteoblastic function, and strong evidence exists of decreased bone formation in smokers. Inaddition,smokershaveasignicantreductionofbonemineralcontent. Bone mineral density can be reduced two to six times in a chronic smoker. Overall, smoking may contribute to poor available bone quality and poor healing capacity resulting from vascular and osteoblastic dysfunction.68ere exist many clinical studies with smoking and sinus graft procedures. Klokkevold evaluated the success rate of dental implantsplacedintheposteriormaxilla;itshoweda7%greaterfailure rate compared with nonsmokers.69 Lindquist showed that smokers can also suer detrimental eects around successfully integrated maxillary implants, with a signicantly greater bleed-ing index, greater mean peri-implant pocket depth, more frequent peri-implant inammation, and radiographically greater mesialand distal bone loss.70 Olson and colleagues found an association between dental implants placed in augmented maxillary sinuses and history of smoking.71Widmarkreportedahigherfailureratein smokers after rehabilitation of severely resorbed maxillae with and without bone graft.72Schwartz-Aradandcolleaguesevaluated212implantsintheposteriormaxilla,resultingina95.5%successrate with nine failures. Of the nine failures, ve were in patients that smoked.73Insummary,smokingisnotanabsolutecontraindicationforsinus graft procedures. However, patients should be instructed to cease smoking before and after sinus graft procedures because of the literature-based studies showing a higher risk of wound dehis-cence,graftinfectionand/orresorption,andareducedprobabilityofosseointegration.Itisrecommended,however,thatifadecisionto proceed with surgery has been made, then patients refrain from smokingatleast15daysbeforesurgery(i.e.,thetimeittakesfornicotinetoclearsystemically)and4to6weeksaftersurgery.More-over, smokers should sign a detailed informed consent in which risks connected to smoking are clearly dened and explained. Relative and Absolute Contraindication to Maxillary Sinus Graft ProceduresIn general contraindications for implant surgery also apply tosinus graft procedures. However, additional specic and local conditions may exist that increase morbidity. Several conditions related to the maxillary sinus are a concern, but they are not neces-sarily contraindications to the sinus graft procedure. e implant clinician,afterevaluationoftheCBCTscanandevaluationofthemaxillary sinus, will in some cases need further medical evalua-tion before proceeding with procedures that may invade the sinus proper. ere exists a wide variation in the severity of the possible pathologic conditions that may be present in the maxillary sinus. For example, a patient may have a mild deviated septum. Because it does not aect the mucociliary clearance of the maxillary sinus • Fig. . Axial contrast-enhanced computerized tomography (bone window) shows almost complete radiopacification of the right maxillary sinus by squamous cell carcinoma. There is destruction of the walls of the sinus and an air-fluid interface in the left sinus. (From Koenig LJ, etal. Diagnostic Imaging: Oral and Maxillofacial. 2nd ed. Philadelphia, PA: Else-vier; 2017.)• Fig. . Antroliths. Any object left in the sinus will calcify and is termed an antrolith. Antroliths usually will result in mucociliary clearance issues. 1008PART VII Soft and Hard Tissue Rehabilitationand there is no associated pathology, no medical consultation byanENTiswarranted.However,ifadeviatedseptumispres-entandsevere,resultinginanonpatentostium,anENTreferralwould be highly recommended.A list of relative and absolute contraindications is listed inBoxes 37.2 and 37.3. Reduction of Sinus Graft ComplicationsEventhoughsinusgraftprocedureshavehighsuccessrates,theseprocedures tend to have a higher risk of infection than implant placement surgery because the patient is predisposed to infec-tionsoriginatingfromtheoralsurgicalprocedure(i.e.,intraoralinfection originating from the surgical site) or from the sinusgraft procedure (i.e., infection within the sinus proper). ere-fore a surgical environment that includes a strict aseptic technique including intraoral and extraoral scrubbing with chlorhexidine, scrubbing and draping the patient, and gowning the doctor and assistant should be considered in addition to sterile gloves and sterile instruments. e risk of postoperative sinus infection is generallylessthan5%whentheseproceduresandapreoperativeand postoperative pharmacologic regimen are used.73,74Prophylactic MedicationsSystemic Antimicrobial Medicationse risks of bacterial contamination before and after sinus graft procedures are much dierent than routine implant surgical pro-cedures. erefore the pharmacologic protocol for sinus graft pro-cedures should be eective against the organisms in this surgical site. e recommended pharmacologic regimen includes a pro-phylacticantibiotic,anti-inammatorymedications,andantimi-crobial rinses.Comparedwithroutinedentalimplantsurgery,sinusaugmen-tation has a greater chance of morbidity because of the possible additional routes of infection. Bacterial invasion may originate fromdierentsourcessuchas(1)intraoralsurgery,(2)bonegraftmaterial, and (3) bacteria from the sinus cavity. Additionally, ithas been well documented that the inclusion of foreign bodies (e.g.,implants,autografts,allografts)increasesinfectionrates.75,76 Because a greater chance of infection and morbidity exists with this type of surgical procedure, a strict antibiotic protocol is of benet. Antibioticmedicationshavebeenshowntosignicantlyreducethenumber of sinus graft or implant failures caused by infection.77Following the principles of prophylactic antibiotic administra-tion, the antibiotic should be eective against the bacteria most likely to cause infection. e most likely contaminating organisms after intraoral surgery are primarily streptococci, anaerobic gram-positive cocci, and anaerobic gram-negative rods. S. pneumoniae, H. inuenzae, and M. catarrhalis are the three most common patho-gens found within the maxillary sinus that may lead to acute sinus infections.78 S. aureusisnotcommonwithacuteepisodes;however,it has been shown to have a signicant role in causing chronic rhi-nosinusitis disease, along with anaerobic bacteria. e organisms associated with infection in general oral surgical procedures include α-hemolytic streptococci and S. viridans.79 erefore a pharmaco-logic protocol should be eective against these organisms.Whenevaluatingvariousclassesofantibioticmedicationsusedfor treatment of maxillary sinus infections, the antibiotic class of choice is the β-lactamantibioticdrugs.Withthe widerangeof possible routes of bacterial invasion and types of bacteria, the antibiotic drug must be broad spectrum to account for all these possibilities. However, bacterial resistance has become a signi-cant problem in the treatment of these pathogens. Bacterial resis-tanceisinitiatedbytwocommonmechanisms:(1)productionofantibiotic-inactivatingenzymes(S. aureus, H. inuenzae, and M. catarrhalis)and(2)alterationintargetsite(S. pneumoniae).Stud-ieshaveshownthefollowingresistance(i.e.,β-lactamase produc-tion)results80:H.inuenzae:36.8%M.catarrhalis:98%S.pneumoniae:28.6%Becauseofthehighrateofbacterialresistance,amoxicillin(thedrugofchoiceformanyyears)isnolongerrecommendedforanti-bioticprophylaxisforthesinusgraftsurgery.Instead,amoxicillin-clavulanate(Augmentin)isusedbecausetheadditionofclavulanicacidenhancesamoxicillin’sactivityagainsttheβ-lactamase–pro-ducing strains of bacteria.e patient with a history of nonanaphylactic allergic reaction to penicillin may take cefuroxime axetil (Ceftin) as an alterna-tive.81Ceftinisasecond-generationcephalosporinthatpossessesgood potency, eciency, and strong activity against resistant S. pneumoniae and H. inuenzae.Ifapatienthasatruehistoryofanaphylactic reaction to penicillin, recurrent sinus infections, or No referral1. Mildmucosalthickening2. Smallcyst(<8mm)3. HistoryofmildSinusitiswithnoradiographicevidenceofpathologyReferral recommendation1. Air-uidLevel2. Cyst(~>8mm)3. Primary/secondarymucocele4. Polyps5. Opaciedsinus6. Chronicsinusitis(MRSA,fungal)7. Bonywallexpansion/destruction8. Previoustrauma8. Foreignbodyinsinus10. EarlylearningcurveENT, Ear, nose, and throat (otolaryngologist); MRSA, methicillin-resistant Staphylococcus aureus. • BOX 37.3 Medical Consultation: Otolaryngologist (ENT)Relative contraindications:1. Limitedanatomic/structuralimpairmentsofthesinusornasalwallsthatarecorrectable(i.e.,deviatedseptum)2. Inammatory/infectiousprocessesthataretreatable3. Foreignbodies4. OroantralstulasAbsolute contraindications:1. Anatomic/structuralimpairmentsofthesinusornasalwallsthatarenoncorrectable.2. Inammatory/infectiousprocessesthatcannotberesolved(i.e.,chronicrhinosinusitis)3. Fungalorgranulomatousdiseasesofthenasosinus.4. Benign/malignantneoplasmsofthenasosinus. • BOX 37.2 Absolute versus Relative Contraindications 1009CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerya recent history of antibiotic use, then doxycycline may be used. In the past, the quinolone class of antibiotics (e.g., Levaquin,Avelox)havebeenusedwithexcellentsuccessbecausetheyexhibitsuperior activity against most types of involved bacteria. However, recentlythe Food and Drug Administration (FDA) has recom-mended the adverse eect of tendon damage does not warrant its routine use anymore.Maximum eectiveness of prophylactic antibiotic drugs occurs when the antibiotic is in adequate concentrations in the tissue before bacterial invasion is initiated. Because the sinus mucosa has limitedbloodsupplywhen infection and inammation is pres-ent, poor antibiotic blood levels are achieved. erefore to combat possible bacterial invasion from the sinus surgery, antibiotic medi-cationsshouldbeadministeredatleast1fullday(24hours)beforesurgeryandextendedforapproximately5daysaftersurgery. Local Antibiotic Medicationse antibiotic concentration within a blood clot of the sinus graftdependsonthesystemicbloodtiter.Aftertheclotstabilizes,furtherantibioticdrugsdonotentertheareauntilrevasculariza-tion.82 e bone graft is a dead space with minimum blood supply andabsenceofprotection by the host’scellular defense mecha-nisms. is leaves the graft prone to infections that would nor-mally be eliminated by either the host defenses or the antibiotic. e osteogenic induction of autografts and allografts is greatly retarded when contaminated with infectious bacteria.83 To ensure adequateantibioticlevelsinanSAgraft,itisrecommendedtoaddantibiotic to the graft mixture.84,85 is local antibiotic may pro-tect the graft from early contamination and infection. Numerous studies have shown that an antibiotic added to graft material has nodeleteriouseects onbonegrowth.Antibioticdrugssuchaspenicillin, cephalosporin, and clindamycin, even in high concen-trations, have not been found to be destructive to bone-inductive proteins.86e locally delivered antibiotic should have ecacy againstthe most likely organisms encountered. Because the incidence of allergy is so high with β-lactam antibiotic drugs, the parenteral formofcefazolin(Ancef)isrecommended.Ifthereexistsatrueallergytopenicillin(i.e.,anaphylactic),thenCleocinmaybeusedas an alternative. Orally administered capsules and tablets should not be used within the graft because they contain llers that inter-fere with bone regeneration.Clinical experience indicates that less risk of infection existswhen preoperative and postoperative antibiotic drugs are used both orally and in the graft. Because infection considerably impairs bone formation for patients undergoing sinus graft pro-cedures,oralantibioticcoverageiscontinuedforapproximately5daysafterthesurgery.Recommendedantibioticdrugsareshownin Box37.4. Oral Antimicrobial RinseAnadditionalantimicrobialmedicationusedwithrespecttosinusaugmentation surgery is chlorhexidine gluconate. is category of antimicrobial rinse has been shown to successfully decrease infec-tious episodes and minimizes postoperative complications fromthe incision line.87 Gentle oral rinses of chlorhexidine gluconate 0.12%shouldbeusedtwicedailyfor2weeksaftersurgeryoruntilthe incision line is completely healed.88 Glucocorticoid MedicationsSinus augmentation surgery usually results in increased post-operative inammation. erefore a pharmacologic regimenis recommended to decrease postoperative edema. Glucocor-ticoidshavebeenwelldocumentedtodecreaseinammationofthesoft tissue and minimize postoperativepain,swelling,andincisionlineopening.Inaddition,theclinicalmanifesta-tions of surgery on the sinus mucosa also can be decreased by use of a glucocorticoid medication.89 erefore the usual surgi-cal protocol for most implant surgeries, including sinus grafts, includesashort-termdoseofdexamethasone(Decadron)(Box 37.5).Toensurepatencyoftheostiumandminimizeinam-mation in the sinus before surgery, steroid medications are ini-tiated1fulldaybeforesurgery.ismedicationshouldalsobeextended 2 days postoperatively because edema peaks at 2 to 3 days postsurgery. Decongestant MedicationsSympathomimetic drugs that inuence α-adrenergic receptors have been used as therapeutic agents for the decongestion of mucous membranes. Both systemic and topical decongestant medications are useful in reopening a blocked sinus ostium and facilitating drainage. Oxymetazoline 0.05% (Afrin or VicksNasalSpray)andphenylephrine1%areusefultopicaldeconges-tantmedications.e vasoconstrictor action ofoxymetazolinelastsapproximately5to8hours,whichispreferredcomparedwith 1 hour for phenylephrine. However, decongestant drugshave many disadvantages. Topical decongestant drugs can cause a rebound phenomenon and the development of rhinitis medi-camentosaifusedmorethan3to4days.eeectivenessofthetopical decongestant is markedly enhanced by proper position of thepatient’sheadduringadministrationofthedrug.ItshouldSystemic Antibiotic Prophylaxis1. Augmentin(amoxicillin-clavulanicacid)(825mg/125mg),onetabletbidstarting1daybeforesurgeryand5daysaftersurgery Non-anaphylactic allergy to penicillin2. Ceftin(cefuroximeaxetil)(500mg),,onetabletbidstarting1daybeforesurgeryand5daysaftersurgery Anaphylactic allergy to penicillin3. Doxycycline(100mg),onetabletbidstarting1daybeforesurgeryand5daysaftersurgery Local Antibiotic in Graft1. Ancef(Cefazolin1gm):Dilutewith2mLsaline(500mg/mL)a. 0.2mLor100mg:addtocollagenmembraneb. 0.8mLor400mg:addtograftmaterial2. Clindamycin150mg/1mLa. 0.2mLor30mg:addtocollagenmembraneb. 0.8mLor120mg:addtograftmaterialbid, Twice a day. • BOX 37.4 Recommended Prophylactic Antibiotic Drugs for Sinus Grafting ProceduresDexamethasone (4 mg) × 6 tablets• Twotablets(8mg)inthemorning,thedaybeforesurgery• Twotablets(8mg)inthemorningofsurgery• Onetablet(4mg)inthemorning,thedayaftersurgery• Onetablet(4mg)inthemorning,theseconddayaftersurgery • BOX 37.5 Glucocorticoid Protocol 1010PART VII Soft and Hard Tissue Rehabilitationalsobe noted that thepulseamplitude and bloodowin thesinus mucosa is reduced with decongestant drugs, such as oxy-metazoline.ismay,inturn,decreasethedefensemechanismwithin the tissues.90Asaconsequenceofthemedicalandlocalrisksofdeconges-tant medications, the modied sinus graft pharmacologic proto-col no longer recommends the prophylactic use of decongestant medications. Analgesic MedicationsInmostcases,sinusgraftproceduresusuallyrequireverymini-malpostoperativeanalgesiccoverage.Ifanarcoticisrequired,any analgesic combination containing codeine, such as Tyle-nol 3, is prescribed postoperatively because codeine is a potent antitussive, and coughing may place additional pressure on the sinus membrane and introduce bacteria into the graft. e patient is instructed to cough (if necessary)with the mouthopen so excessive air pressure does not occur through the ostium. CryotherapyWithsinuselevationprocedures,postoperativeinammationinthe posterior maxilla is very common because of the extent of tis-suereection.Becausepostoperativeswellingcanadverselyaecttheincisionline,measuresshouldbetakentominimizethiscon-dition.Applicationofcolddressingsandcoldoralliquids,alongwith elevation of the head and limited activity for 2 to 3 days, willhelpminimizetheswelling.eappliedcolddressingandliquids will cause vasoconstriction of the capillary vessels, reduc-ingtheowofbloodandlymph,resultinginalowerdegreeofswelling.Iceorcolddressingsshouldonlybeusedfortherst24to48hours.After2to3days,heatmaybeappliedtotheregiontoincreasebloodandlymphow,whichhelpstocleartheareaoftheinammatoryconsequences.isalsoassistsinthereduc-tion of ecchymosis that may have occurred from the bleeding andtissuereection. Aseptic TechniqueBecauseoftheextentoftissuereection,techniquesensitivityof sinus surgery, and need for asepsis, oral or conscious seda-tionisusuallyrecommendedforsinusgraftprocedures.Aftersedation and adequate inltration anesthesia (i.e., posteriorandmiddlealveolarnerve,greaterpalatinenerve)areobtained,the patient is preparedfor surgery.Preparationof the surgi-cal site is important in sinus manipulation surgery to reduce contaminationbythepatient’sownnormalora.eoralcav-ity cannot become a sterile environment for surgery. However, intraoral preparation before surgery may signicantly reduce the bacterial count in the mouth. Studies reveal a signicant reduction in bacteremia during extractions and implant sur-gery complications after preparation with antiseptic mouth rinse.89,90Iodophor compounds (Betadine) are a most eective anti-septic. However, because the iodine is complexed with organic surface-active agents, it has been shown to inhibit the osteoinduc-tionofallograftbone.ereforetheuseof0.12%chlorhexidinegluconate(Peridex)scrubandrinseismostoftenusedasintraoralpreparationofthesurgicalsiterequiringabonegraft.Extraoralpresurgical scrubbing of the skin should also be performed with chlorhexidine antiseptics prior to surgery. Surgical Treatment of the Maxillary Sinus: HistoryIntheearly1970s,Tatumbegantoaugmenttheposteriormaxillawith autogenous rib bone to produce adequate vertical bone for implant support.91,92 He found that onlay grafts below the exist-ing alveolar crest would decrease the posterior intradental height signicantly, yet very little bone for endosteal implants would be gained.ereforein1974TatumdevelopedamodiedCaldwell-Lucprocedureforsinusaugmentation(SA)grafting.ecrestofthe maxilla was infractured to elevate the maxillary sinus mem-brane.Autogenousbone was then added in the area previouslyoccupied by the inferior third of the sinus. Endosteal implantswereinsertedinthisgraftedboneafterapproximately6months.Implantswerethenloadedwithnalprosthesesafteranadditional6months.In1975Tatumdevelopedalateral-approachsurgicaltechniqueto elevate the sinus membrane and place implants simultaneously. e implant system used was a one-piece ceramic implant, and apermucosalpostwasrequiredduringthehealingperiod.Earlyceramic implants were not designed adequately for this procedure, andresultswiththetechniquewereunpredictable.In1981Tatumdeveloped a submerged titanium implant for use in the posterior maxilla and achieved predictable results.From 1974 to 1979, the primary graft material for sinusgrafts was autologous bone. In 1980 Tatum55,93 further expandedtheapplicationof the SA augmentation techniquewith a lateral maxillary approach and the use of synthetic bone. e same year, Boyne and James rst reported on the sinusgrafttechniqueusingautogenousboneforSAgrafts.60 Most of thepublicationsinthe1980swereanecdotalorbasedonverysmallsamplesizes. Treatment Classifications for the Posterior MaxillaIn1984,Misch61organizedatreatmentapproachtotheposteriormaxilla based on the amount of bone below the antrum, and in 1986heexpandedthetreatmentapproachtoincludetheavailablebonewidththatwas relatedto implant design. In1987 Mischincludedthe techniqueofthe sinusoorelevation throughtheimplant osteotomy before implant placement.62 He reported on 170sinusgraftcases,withtwocomplicationsandanuneventfulresolution.In the Misch SA classication, the treatment modality isdependentontheavailableboneheightbetweentheooroftheantrum and the crest of the residual ridge in the region of the idealimplantlocations.eSAprotocolalsosuggestedasurgi-cal approach, bone graft material, and a time table for healing beforeprosthetic reconstruction. In 1995 Misch94 modied his 1987classicationstoincludethelateraldimensionofthesinuscavity;thisdimensionwasusedtomodifythehealingperiodpro-tocolbecausesmallerwidthsinuses(0–10mm)formbonefasterthanlargerwidth(>15mm)sinuses.eDivisionA–widthridgewasalsoincreasedto6mmtopermitmorebonetoencompassthe implant on each side. In 2017 Resnik modied the Mischclassication to include alternative treatment options with short implants, crestal grafting approaches, and treatment plan modi-cations based on force-related factors, which are detailed in Box 37.6(Figs.37.25–37.28).  1011CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgerySurgical TechniqueSubantral Option One: Conventional Implant Placemente rst Misch SA treatment option, SA-1, occurs when su-cient bone height is available to permit the placement of endosteal implants following the usual surgical protocol, with no maxillary sinus involvement. Because the quality of bone in the posterior max-illaoftenisD3orD4bone,bonecompactionorosseodensicationto prepare the implant site is common. is technique permits a morerigidinitialinsertionoftheimplantandalsoincreasestheBIC.Required Bone DimensionsIntheabundantbonevolume(DivisionA),theminimumidealboneheightfortheSA-1isrelatedtotheassociatedforcefac-tors.Underfavorableconditions,aminimumof8mmofboneisrequiredfromthecrestoftheridgetotheinferioroorofthesinusfortheplacementofan8-mmimplant.eliteraturehasconcludedthatshort implants(8 mm)havebeenshowntobesuccessfulintheposteriormaxilla.Ifmultipleimplantsare placed, then ideally the implants should be splinted for force distribution. For unfavorable conditions, greater than 10mmofbone isrequiredinheighttoallowforplacementof an implant so it does not invade the maxillary sinus. is willallowanimplant of 10mmin lengthtobe placed thatwillallowforagreaterinsertiontorqueandBIC.ereforetheimplant will be less likely to have force-related eects that may cause micromovement during the healing phase and poorer healing(Fig.37.29).Because the maxillary sinus proper is not invaded during an SA-1 approach, it is less critical if preexisting pathology in thesinus is present. However, if pathology is present that warrants medical referral, then this should be completed before any implant placement. erefore in general the sinus pathologic contraindi-cations for sinus graft surgery do not apply for implant insertion when adequate bone is present below the sinus for implants of adequatesizeto support the load of the prosthesis.Althoughacommon axiom in implant dentistry is to remain 2 mm or more fromanopposinglandmark,thisisnotnecessaryintheSAregion.Narrowerbonevolumepatients(DivisionB)inSA-1maybe treated with osteoplasty or augmentation to increase the widthofbone.einsertionofsmallersurfaceareaimplants(assmall-diameterroot-formimplants)arenotsuggestedbecausethe forces are greater in the posterior regions of the mouth, and thebonedensityislessthaninmostregions.Inaddition,thenarrow ridge is often more medial than the central fossa of the mandibular teeth and will result in an oset load on the res-toration, which will increase the strain to the bone. However, multiple narrow diameter implants may be placed to support onetooth(i.e.,twonarrowdiameterimplantstosupportonemolar).OsteoplastyintheSA-1posteriormaxillamaychangetheSAcategoryiftheheightoftheremainingboneissucienttoallowforadequatebonepostosteoplasty.Augmentationforwidthmaybe accomplished with bone spreading, membrane grafting, or autogenous grafts. Larger diameter implants are often required in the molar region, and bone spreading to place wider implants is the most common approach when the bone density is poor. Iflessthan 2.5 mm ofwidthis availableinthe posterior edentu-lousregion(C–w),thenthemostpredictabletreatmentoptionistoincreasewidthusingonlayautogenousbonegrafts.Aftergraftmaturation the area is reevaluated to determine the proper treat-ment plan classication.EndostealimplantsintheSA-1categoryarelefttohealinanonfunctionalenvironmentforapproximately4to8months(dependingonbonedensityandforcefactors)beforetheabut-mentpost(s)areaddedforprosthodonticreconstruction.Careistakentoensurethattheimplantsarenottraumatizedduringtheinitialhealingperiod.Progressiveloadingduringthepros-theticphasesofthetreatmentissuggestedinD3orD4bone(Box 37.7). Favorable Conditions• Goodqualityofbone(D2/D3bone)withthepresenceofcorticalbonepresent• Minimalocclusalforcefactors• Noparafunction• Idealcrown/implantratio Unfavorable Conditions• Poorqualityofbone(D3/D4bone)withnocorticalbonepresent• Increasedocclusalforcefactors• Parafunctionalforcespresent• Poorcrown/implantratio • BOX 37.6 Force-Related FactorsBA• Fig. . Bone quality. (A) Thick cortical bone and a dense cancellous bone, which is consistent with a D2 type of bone, (B) No cortical bone present, with very fine trabecular bone, which is usually consistent with D4 bone and mainly found in the posterior maxilla. 1012PART VII Soft and Hard Tissue RehabilitationSubantral Option Two: Sinus Lift and Simultaneous Implant PlacementesecondSAoptionintheMischSAclassication,SA-2,isselectedwhentheintendedimplantlengthis1to2mmgreaterthantheverticalbonepresent(Fig.37.30).Inthistechnique,1to 2 mm may be achieved via elevating the sinus membrane with-out bone grafting. Tatum95 originally developed this technique in 1970, and Misch96 rst published it in 1987. Summers97 published a similar procedurein 1994, 24 yearsafterTatum’srst presentation.BecausetheSA-2surgicalapproachmodiestheoorofthemaxillary sinus, a preexisting pathologic condition of the sinus should not be present because it may aect the implant site by retrograde infection.istechniqueisreservedfor8to10mmofhostbonebelowthe sinus in which an implant is placed via an osteotome tech-niquethatelevatesthemembraneapproximately1to2mmwiththeuseofnografting.Ideally,an8-mmimplantisusedwithcau-tion in these cases.RationaleInsome situations, a longer implantmayberequiredforpros-theticsupport andinitialxation.Worthand Stoneman98 have reported a comparable phenomenon of bone growth under an elevatedsinusmembranecalleda“haloformation”.eyobservedthe natural elevation of the sinus membrane around teeth with periapical disease. e elevation of the membrane resulted in new boneformationonce the tooth infection was eliminated.InanarticlebyPalmaandcolleagues99 the elevation of the sinus mem-brane in implant insertion, with or without a graft material below the mucosa, gave similar results in primates regarding implant stabilityorBICafterhealing.AsaresultoftheautologousbonepresentabovetheapicalportionoftheimplantwithanSA-2tech-nique,andthesinusoorfracture(whichincreasestheregionalaccelerated phenomenon of bone repair and formation), newbone formation over the implant apex is predictable. Incision and ReflectionInanedentulousposteriormaxilla,afull-thicknessincisionismadeon the crest of the edentulous ridge from the tuberosity to the distal ofthecanineregion.Avertical,lateralreliefincisionismadeatitsdistal and anterior extension of the crestal incision for approximately 5mm.Ifminimalattachedtissueexistsonthecrestoftheridge,which is more often observed in the premolar region, then the pri-maryincisionismademorepalataltoplacemorekeratinizedtissueonthefacialaspect.Whenteetharepresentintheregion,thecrestalincisionextendsatleastonetoothbeyondtheedentuloussite.Ifonetoothismissing,thereectionissimilartoasingle-toothreplace-mentoption,andevenadirect(aplesstechnique)maybeused.Afull-thicknesspalatalapisrstreectedbecausethepalataldense cortical plate facilitates soft tissue reection. Specialatten-tion is given to avoid the pathway of the greater palatine artery or to remain completely subperiosteal so that this structure remains • Fig. . Force factors. The posterior maxilla is very susceptible to force-related issues because of strong muscles such as the temporalis (green) and masseter (red).• Fig. . Parafunction. Forces are significantly increased in patients who exhibit parafunction. In this radiograph, the prominent antegonial notch is consistent with parafunctional forces and masseter hypertrophy.AB• Fig. . Crown/implant ratio. The maxillary posterior region often is confronted with a an increased interocclusal space because of the vertical and horizontal bone resorption. (A) Three-dimensional image showing the apical positioning of implants caused by vertical bone resorption. (B) Cone beam computer-ized tomography interactive treatment planning evaluating the increased crown height space. 1013CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerywithinthesofttissue.elabialmucosaisreectedotheeden-tulous ridge, rather than elevating the tissue from the bone. e crest should not be used to leverage the tissue because the ridge may have minimal cortical bone and a perforation may result. is could result in damage to the residual ridge or possibly even penetrate the sinusornasalcavity.Oncethetissueisreected,thewidthoftheavailableboneisevaluatedtoensurethatitisgreaterthan6-7mmwideandallowstheplacementofDivisionAroot-formimplants. Osteotomy and Sinus Elevation (SA-2)e endosteal implant osteotomy is prepared as determined by the densityofboneprotocol,whichisusuallyD3orD4bone.edepthoftheosteotomyisapproximately1to2mmshortoftheooroftheantrum.Whenindoubtoftheheightdimension,theosteotomy should err on a shorter length. e implant osteotomy is prepared to the appropriate nal diameter, short of the antral oor,byapproximately1mm.Aat-endorcupped-shapeosteotomeisselectedfortheinfrac-tureofthe sinusoor.UsuallyinD3 bone,an osteotomeof thesamediameterasthenalosteotomyisselected.InD4bone,anosteotomyonetotwosizessmallerthanthenalimplantsizemaybeused, performing an osseodensication technique. e osteotome is insertedandtappedrmlyin0.5-to1.0-mmincrementsbeyondthe osteotomy until reaching its nal vertical position, up to 2 mmbeyondthepreparedimplantosteotomy.Aslowelevationofthesinusoorislesslikelytotearthesinusmucosa.issurgicalapproach compresses the bone below the antrum, causes a green-stick-typefractureintheantraloor,andslowlyelevatestheunpre-paredboneandsinusmembraneoverthebroad-basedosteotome.Ifthe osteotome cannot proceed to the desired osteotomy depth after tapping, then it is removed and the osteotomy is prepared again withrotarydrillsanadditional1mmindepth.eosteotomeisthenreinsertedtoattemptthegreenstickfractureoftheantraloor.Care should be exercised when removing the osteotomesfrom the osteotomy site. e osteotome should never be luxated because this will increase the width of the nal osteotomy, leading to less insertion torque. Once the osteotome prepares the implant site, the implant may then be threaded into the osteotomy and extendedupto2mmabovetheoorofthesinus.eimplantis slowly threaded into position so the membrane is less likely to tear as it is elevated. e apical portion of the implant engages themoredenseboneonthecorticaloor,ideallywithboneoverthe apex, and an intact sinus membrane. e implant may extend 0to2mmbeyondthesinusoor,andthe1mmofcompressedbone covering over the implant apex results in as much as a 3-mm elevationof the sinus mucosa(Fig.37.31).Ideally,theimplantdesign should include a convex apex with no apical openings as this design will be less likely to cause a membrane perforation. Modified SA2 TechniquesRosenand associates100,101developed amodicationto the SA-2treatment approach for use at the time of an extraction of a maxil-lary molar. e technique is indicated when the maxillary molar is extracted, the surrounding walls of bone are intact, and no periapi-cal pathologic condition is present. e crest of the ridge to the antraloorshouldbe7mmormoreinheight.Oncethetoothisextracted and the surrounding bony walls conrmed, a modica-tionoftheSA-2techniqueisinorder.A5-to6-mmtrephineburisusedinthecenteroftheextractionsiteandpreparesthebone1to2mmbelowtheantraloor.A5-to6-mm-diameter,at-endedor cup-shaped osteotome and mallet intrudes the core of bone 2 mmabovethesinusoor,creating9mmormoreofverticalbone.Asocketgraftmaybeusedwithintheextractionsocketbutisnotpushed into the surgical space of the sinus because it may perforate thesinusmucosa.After4months,animplantmaybeinserted.SomeauthorshaveusedtheSA-2sinusliftproceduretogainmore than 2 mm of implant vertical height. However, these blind surgical techniques increase the risk of sinus membrane perforation.e success of the intact sinus membrane lift cannot be con-rmedbeforeoratthetimeofimplantplacement.Attemptsto“feel”theelevationofthemembranefromwithinan8-mm-deepimplant osteotomy may cause tearing of the sinus lining.Attempting to elevate the sinus mucosa more than 2 mmthroughanimplantosteotomy3to4mmwideand8mmdeepisnotpredictable.Reiserandcolleagues102 reported that when the sinus elevation was 4 to 8 mm in cadavers, almost 25%resultedinsinusperforation.eimplantosteotomysinusoorBA• Fig. . SA-1 (A and B) Treatment plan which includes implant placement below the maxillary sinus proper.• Favorable conditions:>8mmhostbone(implantapproximately8mminlengthorgreater)• Unfavorable conditions:>10mmhostbone(implantapproximately10mminlengthorgreater) • BOX 37.7 SA-1 Requirements 1014PART VII Soft and Hard Tissue Rehabilitationtechnique is often attempted because of the perceived ease of surgeryofanSA-2techniqueversusalateral-wallortranscrestalapproach. ComplicationsIf a sinus membrane perforation occurred during the initialimplant placement procedure, then bone height growth is less likely to occur. is is the primary reason why only 0 to 2 mm of additional bone height is attempted with this technique. How-ever, even when membrane perforation occurs and/or no bonegrowsaroundtheapicalendoftheimplant,theSA-2techniqueis of benet because the apical end of the implant is surrounded by denser bone. is enhances rigid xation during healing and increasesBIC,leadingtoimprovedloadingconditions.If inad-equate bone is formed around the apical portion of an implant, thenaprogressive-loadingprotocolforD4boneissuggesteddur-ingprostheticreconstruction(Box37.8). Subantral Option Three: Sinus Graft with Immediate Endosteal Implant Placemente third approach to the maxillary posterior edentulous region, SA-3,isindicatedwhenatleast5mmofverticalboneandsuf-cientwidtharepresentbetweentheantraloorandthecrestofthe residual ridge in the area of the intended prosthesis abutment (Fig. 37.32).A residual height of 5 mm for the SA-3 category has beenselectedfortwomainreasons:(1)thisheight(inadequateboneBA• Fig. . (A) SA-3 crestal. Treatment plan that includes implant insertion with bone grafting via the crestal (osteotomy) approach gaining approximately 3 to 4 mm of height. (B) Lateral wall. Treatment plan that includes implant insertion with bone grafting via the lateral-wall approach gaining more than 4 mm of height (i.e., amount of height is determined by size of lateral wall).• Favorable conditions:(>8mmhostbone,ideally10-mmimplant)• Unfavorable conditions:(>10mmhostbone,ideally12-mmimplant) • BOX 37.8 SA-2 RequirementsA B• Fig. . SA-2. (A) Radiograph depicting an SA-2 (maxillary second premolar) and SA-1 (maxillary first molar). (B) SA-2 implant that includes implant insertion with penetration into the maxillary sinus proper 1 to 2 mm without bone grafting. 1015CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerywidthandquality)canbeconsideredsucienttoallowprimarystability of implants placed at the same time as the sinus graft pro-cedure,and(2)becauseoftheamountofresidualbone(5mm),greater blood supply is present, which allows for more predictable and faster healing.AnesthesiaInltrationanesthesiahasbeenusedwithsuccessforsinusgraftsurgeriesinthepast;however,moreprofoundregionalanesthesiais achieved by blocking the secondary division of the maxillary nerve(V2).esinusgraftsurgeryoftenrequiresthereectionofthesofttissueextendingtothezygomaticprocess.Inaddition,several branches of the maxillary division of the fth cranial nerve innervatethesinusmucosa.Assuch,aV2blockisadvantageousfor patient comfort, and this achieves anesthesia of the hemimax-illa, side of the nose, cheek, lip, and sinus area.TwooptionsexistforV2blockanesthesia:(1)highandwithinthe pterygomaxillary tissue behind the posterior wall of the max-illaor(2)atthedepthofapproximately1inchwithalong-gaugeneedlewithinthegreaterpalatineforamen(Fig. 37.33).erstmethod is easier to perform but may injure the pterygoid plexus or the maxillary artery and result in hematoma, or it may fail to reachtheproper landmark.Withthesecondoption,itis moredicult to locate the foramen and negotiate up the canal. Itmay also injure the greater palatine artery or nerve. Too deep an administration with a greater palatine approach may result in the penetrationoftheorbitoor.Possiblesequelaeincludeperiorbitalswelling and proptosis, diplopia, retrobulbar block with dilated pupil, corneal anesthesia, motionless eye, retrobulbar hemorrhage, and optic nerve block with transient loss of vision. However, the success rate is greater, and the clinical risks appear minimal. ere-fore most often, the rst attempt for block anesthesia is within the greaterpalatineforamen;ifunsuccessful,thenthehighposteriorapproachisused.Preventionofthesecomplicationsisensuredbyreduction of the needle depth measurement for smaller patients and the strict application of the technique. Proper angulationduring soft tissue penetration prevents possible entrance into the nasal cavity through the medial wall of the pterygopalatal fossa.Inltration anesthesia is rst administered to the posteriorand middle alveolar nerve and greater palatine nerve. Scrubbing, gowning, and draping of the patient is next. en after the inl-trationis eective,theV2blockis administered.Along-actinganesthetic such as bupivacaine 0.5% (Marcaine) is preferred.Block anesthesia with these agents is longer acting than inltra-tion in the maxilla.103e greater palatine foramen is found using an open-bore instrument(i.e., thehandle ofa mouthmirrorwiththemirrorportionremoved).Pressureisappliedwiththisinstrumentalongthe palatal tissue, at the union of the residual ridge and hard pal-ate, in the region of the second molar. Most often, the open-bore handle will feel and recede into the foramen. Slight pressure for a few seconds then marks the tissue over the opening of the fora-men. A long, 1.5 inch needle is introduced into the foramenfrom the opposite side of the mouth and negotiates the canal for approximately1inch. Surgical Approachesere exist two options for grafting the sinus along with simulta-neous implant placement.AB• Fig. . Anesthesia, V2 block. (A) Greater palatine foramen approach through the greater palatine foramen located 1 cm medial and adjacent to the second molar teeth. (B) Cotton swab may be pressed at the junction of the hard palate and the maxillary alveolar process until it falls into the foramen depression. The needle is advanced perpendicular until bone is contacted slowly at an angle of 45 degrees to the long axis of the hard palate.• Fig. . SA-4. Treatment plan that includes bone grafting via the lateral-wall approach with no implant placement. Implant placement is delayed according to the healing of the sinus graft sites. 1016PART VII Soft and Hard Tissue RehabilitationLateral Wall. ATatumlateralmaxillarywallapproachisper-formed by performing an osteotomy over the lateral wall of the maxillary sinus, infracturing the window, elevating the sinus membrane and window, grafting to the medial wall, and then placingtheimplant(SA-3).Incision and Reection. Acrestalincisionismadeonthepal-atal aspect of the maxillary posterior edentulous ridge from the tuberosity to one tooth anterior to the anterior wall of the maxil-lary sinus, leaving at least 2 mm of attached tissue on the facial aspect of the incision. Because ridge resorption occurs toward the midline at the expense of the buccal dimension, the incision is made with awareness of the greater palatal artery, which proceeds closetothecrestoftheridgeintheseverelyatrophicmaxilla.Ifbleedingfromthepalatalapoccurs,thenahemostatmaybeusedto constrict the blood vessels distal to the bleeding, pressure may be applied over the greater palatine foramen with a blunt instru-ment, or electrocoagulation at the bleeding site may be used.Averticalreliefincisionismadeonthedistaloftheincisiontoenhancesurgicalaccesstothemaxillarytuberosity.Abroad-baseanteriorverticalreliefincisionisalsomadeatleast10mmanteriorto the anterior vertical wall of the sinus. is may result in the incision being made over the distal aspect of the rst bicuspid or canine. e facial soft tissue ap is designed, following generalprinciples, with a base wider than the crest to ensure proper blood supply.epalatalportionoftheapisrstreected,followedbythefacialcrestaltissue,whichisreectedothecrest.e facial full-thickness mucoperiosteal ap is reected toexpose the complete lateral wall of the maxilla and a portion of thezygoma.efacialapshouldbereectedtoprovidecom-plete vision and access to the maxillary lateral wall. e superior aspect of the ap should never approach the infraorbital fora-menbecauseaggressivereectionof the facialapmaycause aneuropraxia type of nerve impairment and damage to this nerve structure.ereectedlabialtissuecanbesuturedtothecheekmucosa,carefullyavoidingtheparotidduct.Allbrousandsofttissue should be removed from the lateral-wall access site to avoid softtissuecontaminationofthebonegraft.Entrappingsofttissuewithin the sinus may lead to formation of a secondary mucocele orsurgicalciliatedcyst.Amoist4x4gauzeora2-4moltwithascrapingmotioneasilyremovesthistissue(Fig.37.34). Access Window. e overall design of the lateral-access window is determined after the review of the CBCT scan, which helpsdetermine the thickness of the lateral wall of the antrum, the posi-tionoftheantraloorfromthecrestoftheridge,theposterioroftheanteriorwallinrelationshiptotheteeth(if present),thepresenceofseptaontheoorand/orwallsofthesinus,andanyassociated pathology within the maxillary sinus.e outline of the Tatum lateral-access window is scored on the bonewitharotaryhandpieceundercopiouscooledsterilesaline.Itisofteneasiertoperformthisstepat50,000rpm(1:1handpiece),butitispossibleevenat2000rpm,dependingonthelateral-wallbone thickness. ere exist multiple techniques to score the sinus window:(1)carbidebur(No.6orNo.8),(2)diamondbur,(3)boneremovalburs(e.g.,Daskbur),or(4)Piezosurgeryunits.Withexperience,therst bur is usually a No. 8roundcarbide, whichscratches the bone and designs the overall window dimension. is burisfollowedwithaNo.8rounddiamond,which“polishes”awaythebonewithinthegroovemadebythecarbidebur.ANo.8rounddiamond bur for the entire process is of benet for an early learning curvebecausecarbideburs“chatter”moreandmaytearthesinusmembrane if the bur inadvertently comes in contact with it.e inferior score line of the rectangular access window on the lateralmaxillaisplacedapproximately1to2mmabovetheleveloftheantraloor(i.e.,whichinanSA-3is>5mmfromthecrest).Iftheinferiorscorelineismadeatorbelowtheleveloftheantraloor,theninfractureofthelateralwallwillbeimpossiblebecausethescorelinewillbeoverhostbone.Iftheinferiorscorelineismadetoohigh(>4mm)abovethesinusoor,thenaledgeabovethesinusoorwillresultinablinddissectionofthemembraneontheoor,whichmayalsoleadtoperforation.e most superior aspect of the lateral-access window should beapproximately2-3mmabovetheplannedimplantlength(i.e.,12-mmimplantwouldrequirethewindowtobe15mmfromtheridgecrest).Asofttissueretractorplacedabovethesuperiormar-ginofthelateral-accesswindow(i.e.,alwaysmaintainedonbone,notsofttissue)helpsretractthefacialapandpreventstheretrac-tor’sinadvertentslipintotheaccesswindow,whichmaydamagethe underlying membrane of the sinus.e anterior vertical line of the access window is scored approximately 1 to 2 mm from the anterior sinus border. eA B• Fig. . Incision/reflection. Full-thickness reflection is necessary to expose the lateral wall. (A) For a single-tooth sinus augmentation, usually the incision extends one tooth on each side of the edentulous site. (B) For a large SA4 edentulous area, the anterior incision must extend 5-10 mm anterior to the anterior wall (approximately distal of cuspid) and posteriorly to the tuberosity. 1017CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerydistalverticallineshouldbemadeapproximately5mmdistaltothemostposteriorplannedimplantsite(i.e.,thiswillallowforadequatespaceiftheimplantpositionischangedmoredistally).Ifthepatientisfullyedentulous,thedistalverticallineshouldbemadeapproximately5mmdistaltotherstmolarposition.Ifthesinusaccesswindowoutlineisdiculttodetermineinrelationto the sinus cavity, then it should err over the antrum rather than over the bone around this structure.Ingeneral,alargeraccesswindowoersmanyadvantages,includ-ing easier access, less stress on the membrane during initial elevation, and ease of additional membrane elevation with instruments because of the direct access that facilitates graft placement. e corners of the access window should always be rounded, not right or acute angles. Ifthecorneranglesaretoosharp,thenmembraneperforationmayoccur from the use of a surgical curette at the corner or during the infracture of the lateral wall. Once the lateral-access window is delin-eated, the rotary bur continues to scratch the outline with a paint-brush stroke approach under cooled sterile saline irrigation, until a bluish hue is observed below the bur or hemorrhage from the site is observed. e expansion of the maxillary sinus after tooth loss pushes the arteries of the membrane to the outside of the structure and just below the surrounding bone. erefore either the bluish hue of the membrane or bleeding in the area are signs of approaching the sinus membrane. is observation should be achieved circumferen-tially around the access window. e access window should not be overprepared in depth because direct contact with the membrane withrotarybursmaycauseaperforation(Fig.37.35).ComplicationsEndosseous Anastomosis. Itshouldbenotedthatthelargestbloodvessel in the lateral wall is from an endosseous anastomosis from the posterior superior alveolar and the infraorbital artery. How-ever, when the lateral wall is very thin in the edentulous patient, the anastomosis will atrophy and become nonexistent. e anas-tomosishasbeenshowntobelocatedapproximately15to20mmfrom the alveolar crest.ehorizontallinesoftheaccesswindowshouldideallynotbepositioned directly over this structure. e vertical lines of the access window often cut through the artery. Because the blood supply may be from either direction, both vertical access lines may have bleeding. is is rarely a concern for vision or blood loss during the procedure. Ifintraosseousbleedingisaproblem,thenthehigh-speeddiamondused to score the window may be used without irrigation and polish the bleeding site, which cauterizes the vessel fromtheheat on thebonywall.Electrocauterymayalsobeusedonthisvessel,ifneces-sary.Ahemostatmaybeused;however,careshouldbeexercisedtoavoidfracturingthelateralwalland/orperforatingthesinusmucosa.Elevatingtheheadandasurgicalspongeappliedtothesiteforafewminutes also aides in the control of hemorrhage. Sinus Membrane Elevation. e rst step in elevating the win-dowistoensurethatthelateralwindowiscompletely“free”fromthehostbone.Aat-endedmetalpunch(ormirrorhandle)andmallet may be used to gently infracture the lateral-access window from the surrounding bone while still attached to the thin sinus membrane.eat-endedpunchisrstpositionedinthecenterofthewindow.Iflighttappingdoesnotgreenstickfracturethebone,thentheat-endedpunchisplacedalongtheperipheryoftheaccesswindowandtappedagain.Ifthewindowdoesnotsepa-rate easily, then the punch is rotated so that only an edge comes in contact with the scored line. is decreases the surface area of the punch against the score line of the window and increases the AD EBC• Fig. . Window preparation. (A) Window osteotomy should be made just through the cortical bone. (B) Initially, an outline form should be completed with a round carbide (No. 8), (C) Final preparation should be completed through the cortical bone with a round diamond (No. 8). (D and E) Osteotomy is complete when the window is free 360°. 1018PART VII Soft and Hard Tissue Rehabilitationstressagainstthebone.Anotherlighttapwiththemalletwillmostlikely cause greenstick fracture of the bone along the scored line. Ifthisstilldoesnotfreethewindow,thenfurtherscoringofthebone with the handpiece and diamond bur is indicated, and the tapping procedure is repeated.Ashort-bladedsofttissuecurettedesignedwithtworight-anglebends is introduced along the margin of the window (i.e., Sal-vinSinusCuretteNo. 1). e curvedportion is placed againstthe window, whereas the sharp edge is placed between the sinus membrane and the margin of the inner wall of the antrum for a depth of 2 to 4 mm. e curette should always stay on theboneandbeusedinascrapingmotion.Ifanysharpedgesofboneremainonthebone’smargin,thentheymaybeickedowiththecurette.ecuretteisslidalongthebonemargin360degreesaround the access window. is ensures the release of the mem-brane from the surrounding walls of the sinus without tearing from the sharp bony access margins. e sinus membrane may be elevated from the antral walls easily because it has few elastic bers and is not attached to the cortical wall. Specially designed and shaped curettes are available to facilitate this surgical maneu-ver.Alargercurvedperiostealorsinusmembraneelevatoristhenintroduced through the lateral-access window along the inferior border(i.e.,SalvinSinusCuretteNo.2).Onceagain,thecurvedportion is placed against the window, and the sharp margin of the curetteisdraggedalongtheooroftheantrumwhileelevatingthe sinus membrane. e curette should always be maintained on thebonyoorto avoidamembraneperforation.ecuretteisnever blindly placed into the access window. e implant clinician shouldseeand/orfeelthecuretteagainsttheantraloororsinuswallsatalltimes.Oncethemucosaontheantralooriselevated,the lateral, distal, and medial wall of the sinus is addressed. e curetteispushedagainst thebonethat easilyreectsthemem-brane. e sinus membrane is inspected for perforations or open-ings into the antrum proper.Itiseasier togaindirect visionand access tothedistal por-tions of the antrum than the anterior portions when the sinus area expands beyond the access window. erefore whenever the peri-osteal elevator or curette cannot stay against the bone with good access in the anterior area, the access window should be increased insizetowardtheanterior.AKerrisonrongeurorasecondwin-dow similar to the initial score-and-fracture technique may be usedtoexpandthesizeoftheaccesswindow.eperiostealelevatorsandcurettesfurtherreectthemembraneotheanteriorverticalwall,oor,andmedialverticalwall.Itisbet-ter to err on the high side to ensure that ideal implant height may be placed without compromise (i.e., always maintaining a patentostium).elateral-accesswindowispositionedaspartofthesupe-riorwallofthegraftsite,onceinnalposition.eSAspacehastheoriginalsinusoorasthebase;theposteriorantralwall,medialantralwall,andanteriorantralwallasitssides;andthelateral-accesswindowandelevatedsinusmucosaasitssuperiorwall(Figs.37.36and37.37). Sinus Graft: Layered Approach. Top Layer: Collagen and Antibiotic. A resorbable collagenmembrane (Oratape) soaked with a parental form of antibiotic(Ancef 0.2 mL) is then prepared (Box 37.9). e collagen andantibiotic are placed onto the elevated antral oor region andattach to the sinus mucosa on the superior part of the graft site. e collagen is a carrier for the antibiotic to decrease the risk of postoperativeinfection.Inaddition,incaseofmembranetearingorseparationofthesinusmucosa(withorwithouttheawarenessoftheclinician),thecollagenmembranesealstheopening(Fig. 37.38).Itisimperativethataportionofthe membranebe leftACDB• Fig. . Sinus membrane reflection. (A) Membrane reflection starts on the floor, (B) is extended to the anterior wall, (C) extended to the posterior, (D) and then to the superior. Curette should always be main-tained on the bone to prevent perforation. 1019CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgeryoutsideofthesinus, preventing “intrusion” of the entire mem-brane into the sinus during bone placement.Second Layer: Sinus Graft Materials. e second layer of the sinus graft layered approach is the most abundant and con-sists of the allograft bone grafting material. Many materials have been proposed in single or combination mixes, including min-eralizedanddemineralizedfreeze-driedbone,104,105 β-tricalcium phosphate (β-TCP),106 xenograft hydroxyapatite (HA) (bovineanorganicbone),andcalciumcarbonates(bioactiveglass).107Inaddition,morerecentresearchhasfocusedoncombining“tradi-tional”bonesubstituteswithbonegrowthfactors.108Eachgraftmaterial used in the sinus graft technique presents a similar, yet distinct, biological approach to the healing process.What Type of Graft Material? Autogenousboneforyearshasbeenconsidered the gold standard of grafting material. Tatum rst de-veloped and reported the use of autogenous bone for sinus grafts inthe1970s,andBoyne109,110andJamesrstpublishedthein-formationin1980.Inprimates(Macaca fascicularis),Misch111,112 found the use of iliac crest or tail bone in sinus grafts produced bone slightly denser than typical in the region, as evidenced from histology sections harvested at the reentry procedure. Similar nd-ings have been observed during case series studies, with patients undergoing sinus grafts with autologous bone from the iliac crest or intraoral donor sites.113Itisinterestingtonotethatsinusgraftsintheliteraturethathaveused100%autogenousbonehavelowersuccessratesthansinusgraftswithsyntheticsubstitutes(e.g.,DelFabbroandcol-leagues114reported87.70%versus95.98%).115 Many additional studieshaveconcludedthat100%autogenousboneresultsinlessbone formation that a composite type of graft. Hallman and col-leagues showedthat sinuses grafted with 100% xenograft com-paredwith100%autogenousexhibitedgreaterhealingandhigherimplant survival rates.116 Froum and colleagues reported that if 20% autogenous bone was added to other bone substitutes, agreater mean vital bone formation was found.117Demineralized freeze-dried bone (DFDB) has been shownto be osteoinductive, which is capable of inducing undierenti-ated mesenchymal cells to form osteoblasts. e mechanism for this process appears to relate to the bone morphogenic protein (BMP)foundprimarilyincorticalbone.Inanimalandhumanstudies,DFDBallograft(DFDBA)powderusedaloneinsinusgrafts did not provide satisfactory results. Bone was present but notinsucientvolumeasthegraftmaterialoriginallyplaced.Speculation exists that the material resorbs more rapidly than the bone formation process, resulting in less bone formation. Inaddition,studieshaveshownthatDFDB,whenplacedintoanareaoflow-oxygentension(hypoxicorhypocellulartissue),results in brous or cartilage tissue rather than bone.118 Other authors have observed similar conclusions on the poor perfor-manceofDFDBusedaloneinanimalandhumanstudies.119AttheSinusGraftConsensusConference,14 high success rates were reported for all materials and combinations, with the exception ofDFDBwhenusedalone.Mineralizedfreeze-driedboneallografts(FDBAs)areanallo-genicbonethatdoesnotundergothedemineralizationprocess.FDBAhasthesameBMPcontentinitsorganicmatrix;however,itdoesnothavethesameosteoinductivecapabilityasDFDBA.FDBAhasbeenshowntobeabetterscaold(osteoconduction)than DFDBA, which allows for superior space maintenance.120 Eventually,osteoclastsbreakdownthemineralcontentofFDBAuntildemineralizationoccurs,inducingnewboneformationanda prolonged protein release.Cammackandcolleaguesexaminedmineralizedanddeminer-alizedfreezedriedallograftusedinsinusaugmentationproceduresand found no statistical signicance between the two bone sub-stitutes.AhistomorphometricstudybyFroumandcolleagues121 at 26 to 32 weeks after grafting evaluated mineralized cancel-lousboneallograft(MCBA)andanorganicbovine bone material (ABBM)forsinusaugmentation.Bilateralsinusgrafts,onelledwithMCBAandtheotherwithABBM,werecompared.eaver-agevitalbonecontentoftheMCBAwas28.25%,comparedwiththeABBMofonly12.44%.ereforemineralizedcorticocancel-lousboneofapproximately250to1000μm is advantageous for AB• Fig. . Window elevation. (A and B) The window should not be “intruded” but elevated. When com-plete, the lateral wall will be at 90 degrees and the medial bone exposed (green arrow).1. Top layer (superior)a. Collagenmembraneb. Localantibiotic(Ancef)2. Middle layer (intermediate)a. 70%mineralizedfreeze-driedboneallograftb. 30%demineralizedfreeze-driedboneallograftc. Platelet-richbrinfrom10mLofwholebloodd. Antibiotic(Ancef500mg/mL)3. Bottom layer (inferior)a. Autogenousbone,tuberosity**Dependent on the amount of host bone present • BOX 37.9 Sinus Graft Layered Technique 1020PART VII Soft and Hard Tissue Rehabilitationbone graft material because it fullls space maintenance require-ments and allows for cell migration.122Allograft bone material is available in three particle forms:cortical,cancellous,andcorticocancellous.Corticalallograftsareassociated with an increased density and greater space maintenance properties,whichallowforslowerresorption.Cancellouschipsareadvantageous because they allow for osteoconductive scaolding anddepositionofosteoblastswhilebeingfasterresorbing.Ideally,the use of corticocancellous bone is advantageous because it allows for both the benets of cancellous and cortical bone to be used in the grafting process.eidealparticlesizeoftheallograftmaterialisveryimportantin the bone regeneration process because too small (<125 μm)particle size leads to fast resorption, with an inconsistent boneformation.Alargerparticlesize(>1000μm)restrictsresorptionand may be sequestered or result in delayed healing. Studies have shownanidealparticlesizeforpredictableboneregenerationtobeapproximately250to1000μm.123Inadditiontothemineralizedbone,bonegraftfactorsintheformofplatelet-richbrinmaybeused.Wholebloodisdrawn(approximately10ml)fromthepatientandplacedintoacen-trifugefor10to15minutesat3000rpm.ebloodissepa-ratedbythecentrifugeintothreelayers:(1)redbloodcells,(2)platelet-richbrin(PRF),and(3)platelet-poorplasma(PPM).ePRFlayercontainsmanygrowthfactorsthatareinvolvedinthecascadeofbonemineralization.124ePRFisaddedtothebone substitutes, along with a local antibiotic to be added into thesinusproper.Aparenteralformofantibioticisusedratherthan a tablet form because oral antibiotic drugs often have llers in the product that are not osteoconductive. e most common antibioticisAncef500mg/mL,and0.8mLofsolutionisaddedtothegraft(Fig.37.39). A B• Fig. . Middle layer. The middle layer consists of allograft (i.e., 70% mineralized, 30% demineralized) plus antibiotic. (A) Allograft syringed into the sinus proper. (B) Packing of the sinus with a packer.BA• Fig. . Top layer. (A and B) Fast-resorbing collagen (e.g., Collatape) is used with antibiotic as the top layer. The collagen membrane should be positioned to the medial wall and with a small segment exposed outside the superior aspect of the window. A longer acting collagen may be used if a known membrane perforation is present. 1021CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgerySummary: 2nd Layer. e second layer of the lateral-wall sinus graft will consist of the following:1.a. 70%mineralizedFDBA,30%demineralizedDFDBAOR b. MineralizedFDBA:(Corticocancellous) • ParticleSize=250–100μm • Approximately250–1000μm2. PRF3. Localantibiotic(Ancef)ese materials are mixed in a surgical bowl and lled into a bone graftingsyringeor1cchypodermicsyringe.Whenplacingthegraftmaterial, insert the syringe into the sinus proper in approximation to the medial wall and material is extruded as the syringe is removed. e grafting material should be deposited in an anterior and inferior direction. is will ensure material raises the lateral window instead of intrusiontowardthemedialwall.Intrusionwillleadtolackofboneformation near the medial wall and may aect implant placement and post-sinus mucociliary function. By extruding the material in the anterior direction, bone graft material will be placed into the anterior segment of the sinus incorporating graft material in contact with the anterior wall and increasing blood supply for healing. e material should be condensed with a serrated packer, and packing pressure shouldbermbutnotexcessive.Inadequatepressurewillresultinair-spaces,whichmaypredisposethegrafttofutureinfection.Excessivecondensation may lead to perforation of the membrane and extrusion of material into the sinus proper.Bottom Layer Regional Acceleratory Phenomenon. e third or bottom layer will consist of multiple steps to enhance bone growth. First, especially iflittlebleedingispresentfromthesinusoorandtheanteriorwall,a sharp instrument (e.g.,scaler,curette)isusedto scratchthe bone. is trauma will initiate the regional acceleratory phe-nomenon(RAP),whichintroducesmoregrowthfactorsintothesite and starts the angiogenesis process. e blood vessels allow migration of osteoclasts and osteoblasts that resorb and replace the graftwithlive,viablebone.Inaddition,thebloodvesselsprovideblood supply to the autologous bone portion of the graft, which is required for initial osteogenesis. e medial wall should not be scratched because it is very thin and perforation may occur. Autogenous Bone. e second part of the third layer is the use of autogenous bone. Osteogenic material is capable of producing bone, even in the absence of local undierentiated mesenchymal cells.Autogenousbonepredictablyexhibitsthisactivityinthesi-nusgraft.Mischhasperformedreentryofmorethan1500sinusgrafts(atimplantplacement)accompaniedbymorethan50hu-manhistologicsectionsand18primatesinusgraftsandhistology.Aconsistenthistologicandclinicalndingisthatbonegrowsintothe augmentation region from the surrounding walls of the max-illary antrum in which the sinus membrane was elevated.125 Inother words, the bone growth came from the surrounding walls of bone, similar to an extraction socket. e last regions to form bone are usually the center of the lateral-access window and the regionundertheelevatedsinusmembrane.Infact,nonewboneattimeintervalsupto12monthswasfoundtogrowimmediatelyunder the sinus membrane.e most common harvest site for the lateral-wall approach is the maxillary tuberosity on the same side of the patient that the sinus is being augmented. In this way, an additional surgical siteis not required, which decreases morbidity to the patient. Addi-tional sources of bone to be added to the graft site may be any bone fragments from implant osteotomy sites, bone cores over the roots of anterior teeth, sinus exostoses, and cores from the mandibular symphysis or ramus region. e autogenous bone is placed on the originalbonyoorintheareamostindicatedforimplantinsertion.Abloodsupplyfromthehostbonecanbeestablishedearliertothisgrafted bone and maintains the viability of the transplanted bone cells and the osteogenic potential of the transplanted bone growth factors.Autogenousbonerepresentsanimportantcomponentofthesinusgraft,andisofmoreimportanceinanSA-4approachcom-paredwithanSA-3,whichhasmorehostbonepresent(Fig.37.40).e harvest of the tuberosity bone is initiated with the expo-sureofthetuberositybone;however,careshouldbeexercisedtonot extend the incision to the hamular notch area because this may result in potential bleeding episodes. Once there is full-thick-nessreectionofthetuberositybone,double-actionrongeursmayremove small pieces of the mainly cancellous bone. e tuberos-ity bone is usually soft and therefore is compressed to form more cells per volume. Usually, rotary burs or bone chisels are not recommended because this reduces the amount of bone grafted and increases the possibility of perforation into the sinus proper. Additionalautogenousbonemaybeharvestedintraorallyorextra-orally,asindicatedonacase-by-casebasis(Fig.37.41).eautogenousboneisthenplacedontheoor bymakingsmallspaceswithacurettewithintheallograftmaterial.Ideally,a space should be made to the medial wall because it is advanta-geous for autograft chips to be placed in approximation to the medialwall.Afterplacementoftheautogenousbone,thegraftedarea is veneered with the allograft material to ll any voids that are present. Implant Insertion. Areview of the literature by Del Fabbroand colleages126 notes success rates of implants placed at the same timeasthegrafthaveasurvivalrateof92.17%,whereasadelayedimplantinsertionhasasurvivalrateof92.93%.e5to10mmofinitial bone heightin an SA-3posteriormaxilla, the corticalbone on the residual crest, and the cortical-like bone on the origi-nal antral oor may stabilize an implant that is inserted at thetime of the graft and permit its rigid xation. erefore when the conditionsareidealfortheSA-3sinusgraft,theimplantmaybeinsertedatthesameappointment.WheninsertingimplantsintoanSA-3sinusgraft,thesinusshouldalwaysbecompletelylledprior to implant placement. Attempting to graft after implantinsertionisverydicultandwillleadtovoids.Whenpreparingthe osteotomy into the grafted sinus, a nger rest should be main-tained so that control of the handpiece is maintained upon perfo-rationintothesinus.Careshouldbeexercisedtonotextendtheosteotomy into the grafted material. is will result in dispersion ofthegraftmaterial.Penetrationthoughtheinferioroorshouldonlybeapproximately1mm,astherewillbenoresistancefromthegraft materialwhen placingthe implant.Inmostcases,theosteotomy will be underprepared to allow for osseodensication (D4 bone). Implant placement is more accurate when insertedwithahandpiece(Figs.37.42and37.44).e advantage of the SA-3 technique is the decreased treat-ment time because the implant and sinus graft are completed at the same time. In addition, there exist several disadvantages ofimmediate implant placement compared with delaying implant placement(i.e.,SA-4approach):1. eindividualrateofhealingofthegraftmaybeassesseddur-ing the healing period, while the implant osteotomy is being prepared and the implant inserted. e healing time for the implant is no longer arbitrary, but it is more patient specic. 2. Under ideal conditions, postoperative sinus graft infections occur inapproximately3% to5% ofpatients,whichisgreaterthanthe percentage for implant placement surgery or intraoral onlay BA• Fig. . Bottom layer. The bottom layer consists of any autogenous bone obtained because the importance of autogenous bone is inversely proportional to the amount of host bone present. (A) harvested bone placed into window. (B) Final bone packing of autogenous bone.A B C• Fig. . SA-3 implant placement. (A) After lateral-wall sinus grafting, the osteotomy is completed, usu-ally after the initial surgical drill, osteotomes are used to widen the osteotomy. (B) Implant placement into graft material. (C) Final veneer grafting over implant site.ABC• Fig. . Autogenous bone harvest. (A) Usually because of access, the maxillary tuberosity is the most ideal location for autogenous harvest. (B) Harvest can be completed with a double-action rongeur. (C) Usu-ally large autogenous pieces may be obtained without penetration into the maxillary sinus. 1023CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerybonegrafts.Ifthesinusgraftbecomesinfectedwithanimplantin place, then a bacterial smear layer may develop on the implant and make future bone contact with the implant less predictable. einfectionisalsomorediculttotreatwhen theimplantsare in place and may result in greater resorption of the graft as a consequence.Iftheinfectioncannotbeadequatelytreated,thenthe graft and implant must be removed. erefore a decreased risk of losing the graft and implant exists if a postoperative infec-tion occurs with a delayed implant insertion. Some reports in the literature indicate a slightly higher failure rate of implants when inserted simultaneously compared with a delayed approach. 3. Blood vessels within the graft are required to form and remodel bone.Animplantinthemiddleofthesinusgraftdoesnotprovideasourceofbloodvessels.Itmayevenimpairthevascularsupply.4. Bone width augmentation may be indicated in conjunctionwith sinus grafts to restore proper maxillomandibular ridge relationshipsand/orincreasetheimplantdiameterinthemolarregion.Augmentationmaybeperformedsimultaneouslywiththesinus graft. Asaresult, largerdiameterimplants may beplaced with the delayed technique.5. eboneinthesinusgraftisdenserwiththedelayedimplantplacement.Assuch,implantangulationandpositionmaybeimproved because it is not dictated by existing anatomic limita-tions at the time of the sinus graft.6. eclinicianmayaccessthesinusgraftbeforeimplantinser-tion. On occasion, the sinus graft underlls a region, and the lack of awareness of the condition during implant insertion at the same time results in an implant placed in the sinus proper, rather than the graft site. 7. On reentry to a sinus graft, it is not unusual to observe a crater-like formation in the center of the lateral-access window, with softtissueinvagination.Iftheimplantisalreadyinplace,thenitmaybediculttoremovethesofttissueandassessitspre-ciseextent.Whensofttissueis presentatadelayed implantinsertion, the region is curetted and replaced with a bone graft before implant placement. e healing time for the implant is related to the developing bone assessed at the delayed surgery, not an arbitrary period that may be, on occasion, too brief. Membranes. Afterimplantplacement,athinlayerofgraftmate-rialmaybeveneeredovertehlateralaccessopening.Aresorbablemembrane (e.g., Collatape) is then placed over the lateral-accesswindow(Fig.37.43).Amembranewilldelaytheinvasionofbroustissue into the graft and will enhance the repair of the lateral bony wall.Anonresorbablemembraneshouldnotbeusedbecausereen-try would be required and the possibility of postoperative sinus infectionwillincrease.Abacterialsmearlayermayaccumulateinthe nonresorbable material and contribute to the infection process. Rarelywillaresorbablemembranebecomeinfected.AB• Fig. . Membrane. (A) Collagen membrane positioning over the lateral window (i.e., may use platelet-rich fibrin over collagen). (B) Final suturing of surgical site.A B• Fig. . SA-3 lateral wall. (A) The sinus should always be grafted before implant placement (B) because grafting is difficult to complete after implant is placed (i.e., cannot graft on medial aspect of implant). 1024PART VII Soft and Hard Tissue RehabilitationPRFmaybeusedasadoublemembranebyplacementoverthe lateral collagen membrane to increase the amount of growth factors for bone formation and to increase the growth factors fortissuehealing.IfinadequatePRFisavailablebecauseitwasusedinthesecondlayerofthegraft,thenPPPmaybeusedbecause platelets are present but in lower quantities. Froum and colleagues127 evaluated sinus grafts with barrier mem-branes over the lateral-access wall compared with no barrier membrane.Allsinusgraftcombinationsinthestudydemon-strated higher vital bone percentage on the cores when a bar-rier membrane was used. Misch observed a higher vital bone percentage even when collagen was used over the lateral-access site compared with no collagen. Tarnow and colleagues com-pleted a split-mouth design study with bilateral sinus grafts, with or without covering the lateral window with a membrane. Histologic samples revealed a higher percentage of bone with a membrane(25.5%)comparedwithnomembrane(19.9%).128 Soft Tissue Closure. e soft tissues and periosteum should be reapproximated for primary closure without tension, with care to eliminate graft particles in the incision line. Because of the access window grafting, along with the double layer membrane, it is often necessary to stretch the tissue to allow for tension-free closure.ereforethefacialapmustoftenbeexpanded,whichusuallycanbecompletedbyperiostealreleaseincisions.Atissuepickupholdsthefacialaptotheheightofthemucogingivaltis-sues junction. e ap is then elevated, and a No. 15 blade isusedtoincisethetissue1mmdeepthroughtheperiosteumabovethe mucoperiosteum. Tissue scissors are then introduced into the incision parallel to the facial ap at a depth of 3 to 5 mm. Abluntdissectionundertheapreleasestheperiosteumandmuscleattachmentstothebaseofthefacialap.eapmaythenbeadvanced over the graft site to the palatal tissues.Itshouldbenotedthathorizontalvascularanastomosesarelocatedlateraltothemaxilla,withinthesofttissue(extraosse-ousanastomosis),andapproximately20mmabovethecrestoftheridge.Abluntdissectiondoesnotviolatethesevessels.Notensionshouldexistonthefacialapwithprimaryclosureofthesite.Interruptedhorizontalmattressoracontinuoussuture(3-0polyglycolicacid[PGA])maybeplaced.Suturingismorecritical with this procedure than with many other implant place-ments.Incisionlineopeningmaycontributetoinfection,con-tamination,orlossofgraftmaterials.ebordersandangeofan overlaying soft tissue–borne denture or partial denture areaggressively relieved to eliminate pressure against the lateral wall of the maxilla.Crestal Approach. e second option for an SA-3 sinusaugmentation and implant placement is the use of the crestal approach. is approach has become more popular for reducing complications from lateral-wall sinus augmentation procedures. e crestal approach sinus augmentation uses an osteotome to breakthroughtheoorandthengraftbelowthesinusmembrane.e following are the ve steps used in the procedure: Step1:Aconventionalfull-thicknessapwithcrestalincisioniscompletedtogainaccesstothebonyridge.Apilotdrillisusedtoperformtheinitialosteotomy1to2mmshortofthesinusoor. e exact measurement of the available bone is com-pletedviaCBCTimages.Incrementallylargersurgicaldrillsorosteotomes should be used to widen the osteotomy, at least one drill short of the nal implant width.Step2:Asmalldiameterosteotomeisinsertedintothepreparedsitetocompressthesinusoorusingasurgicalmallet.Aslight“give”willoccurwhentheboneisbreached.Aperiapicalradio-graphmaybetakentoverifypositioning.Incrementalwiderosteotomes are inserted to expand and to obtain vertical expan-sion of the bone height to accommodate the implant diameter.Step3:Afterthelastosteotomeisused,bonegraftmaterialisslow-ly introduced into the osteotomy site. First, a PRF coagulantmaybe placed into the osteotomy site. is will allow for en-hanced soft tissue healing via penetration through the collagen membrane to increase bone growth. Second, collagen is tapped intopositiontoelevatethemembrane.Asmallpieceofcollagen(i.e.,approximately1½largerthantheosteotomyhole)isplacedinto the osteotomy site, with the last osteotome. e collagen will act as a buer between the bone graft material and the sinus membrane. e collagen is less likely to perforate the membrane.Step4:egraftmaterialisslowlyintroducedintothesinusoste-otomy with a bone graft spoon or an amalgam carrier. e si-nusooristhenelevatedbyrepeatedincrementsofbonegraftmaterial and placed into position with an osteotome.Step5:Oncetheosteotomyiswidenedandsinusmembraneiselevated to the desired height, the implant may be inserted. is SA-3 crestal technique has the advantage of surgical sim-plicity, which decreases possible surgical morbidity. e main disadvantage of this technique is the unknown perforation of the sinus membrane. Ideally,the sinus membrane integrity should bemaintained during the procedure. e limitations of this technique includeelevatingthemembraneapproximately3to4mm.Ifgreaterheightisrequired,thelateral-wallapproachmaybeused(Figs.37.45and37.46;Box37.10). Subantral Option Four: Sinus Graft Healing and Extended Delay of Implant InsertionInthefourthoptionforimplanttreatmentoftheposteriormax-illa,SA-4,theSAregionforfutureendostealimplantinsertionisrstaugmented,thenaftersucienthealing,implantplacementiscompleted.isoptionisindicatedwhenlessthan5mmremainsbetweentheresidualcrestofboneand theoor ofthemaxillarysinus(Fig.37.47).Inaddition,ifanSA-3approachiswarrantedbecauseonly5mmofboneispresent,butpathologyispresent,itisoftenadvantageoustocompleteanSA-4technique.eSA-4cor-responds to a larger antrum and minimal host bone on the lateral, anterior, and distal regions of the graft because the antrum gener-ally has expanded more aggressively into these regions. e inad-equate vertical bone in these conditions decreases the predictable placement of an implant at the same time as the sinus graft, and lessrecipientboneexiststoactasavascularbedforthegraft.Inaddition, in most cases, less autologous bone exists in the tuberosity forharvesting,andfewerseptaorwebswillexistinthesinus(andtypically exhibit longer mediodistal and wider lateromedial dimen-sions).ereforethefewerbonywalls,lessfavorablevascularbed,minimal local autologous bone, and larger graft volume all mandate a longer healing period and slightly altered surgical approach.e Tatum lateral-wall approach for sinus graft is performed as inthepreviousSA-3procedurewithouttheimplantinsertion(Fig. 37.48).MostSA-4regionsprovidebettersurgicalaccessthantheirSA-3counterpartsbecausetheantrumoorisclosertothecrest,comparedwiththeSA-3posteriormaxilla.However,inDivisionDmaxillae,itisusuallynecessarytoexposethelateralmaxillaandthezygomaticarch.e access windowintheseverelyatrophicmaxillamayevenbedesignedinthezygomaticarch.Ingeneral,the medial wall of the sinus membrane is elevated approximately 1025CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery12mmfromthecrestsothatadequateheightisavailableforfutureendosteal implant placement. e combination of graft materi-alsusedandtheirplacementareidenticaltotheSA-3techniquelateral-wall approach. However, because less autogenous bone is often harvested from the tuberosity, an additional harvest site may be required, most often above the roots of the maxillary premolars orfromthemandible(i.e.,ascendingramus).e width of the host site for most edentulous posterior maxillae isDivisionA.However,whenDivisionC–wtoDexists,amem-braneoronlaygraftforwidthisindicated.Whenthegraftcannotbe secured to the host bone, it is often better to perform the sinus graft6to9monthspriortotheautogenousgraftforwidth.Afterthegraftmaturation,theimplantsmaybeinserted(Box37.11).Vascular Healing of GraftHealing of the sinus graft takes place by several vascular routes, including the endosseous vascular anastomosis and the vasculature ofthesinusmembranefromthesphenopalatineartery.Inmildlyresorbed ridges, the host bone receives its blood supply from both centromedullary and mucoperiosteal vessels. However, as age and the resorption process increases, the bone gradually becomes totally dependent on the mucoperiosteum for the blood supply. e periphery of the graft is mainly supplied by vessels of the sinus membrane and by intraosseous vascular bundles. e central por-tions of the graft receive blood from collateral branches of the endosseous anastomosis. e extraosseous vascular anastomosis may enter the graft from the lateral-access window.Many local variables are related to sinus graft maturation, includinghealingtime,thevolumeoftheSAgraft,thedistancefromthelateraltomedialwall(small,average,orlarge),andtheamount of autologous bone in the multilayered approach, all of which relate to the speed and amount of new bone formation.e time of evaluation of the sinus graft is perhaps the great-est variable of all. Froum and colleagues129,130 evaluated a sinus graftfromthesamepatientat4months,6months,12months,and20months.eamountofnewbonecontinuouslyincreased,comparedwith the amount of graft material in the antrum. Inaddition, the additional time allowed the graft to mature into a loadbearingtypeofbone.Insummary,themoretimethatelapsedfrom sinus graft to implant loading, the more vital bone was avail-able to support the occlusal load.e type of bone graft material used in the sinus graft may aect the rate of bone formation. Bone formation is fastest and most com-pletewithintherst4to6monthswithautogenousbone,followedbythecombinationofautogenousbone,porousHA,andDFDB(6–10months);alloplastsonly(i.e.,TCP)maytake24monthstoABCDEPRFCollagen PRFCollagen Bone graftPRFCollagen Bone graft• Fig. . Crestal approach. (A) Step 1: Initial osteotomy short of sinus floor. (B) Osteotome used to widen osteotomy. (C) Platelet-rich fibrin and collagen membrane placement. (D) Allograft material placement. (E) implant placement. 1026PART VII Soft and Hard Tissue Rehabilitationformbone.etimerequiredbeforeimplantinsertionforSA-4orimplant uncovery is dependent on the volume of the sinus graft. Mosthealedsinusaugmentations(i.e.,especiallySA-4)willbetheD4typeofbone;thereforeosseodensicationsurgicalapproachandprogressive bone loading techniques should be strictly followed. Postoperative Instructionse postoperative instructions are similar to those for most oral surgicalprocedures.Rest,ice,pressure,andelevationoftheheadare particularly important. Strict adherence to the pharmaco-logic protocol as mentioned previously is vital to decrease postop morbidityis ofmajor importance. Althoughsmoking isnotanabsolute contraindication for sinus grafting, smoking during the healing period may negatively aect the healing and increase the possibility of postoperative infections.Blowing the nose and/or creating negative pressure whilesucking through a straw or cigarettes should also be eliminated for the 2 weeks after surgery. Block and Kent131 reported on a patient who lost the entire sinus graft 2 days after surgery from AB CDE FGHI• Fig. . Crestal approach. (A) Initial osteotomy completed via fully guided template 1 mm short of the sinus floor, (B) Sequential osteotomes are used to infracture sinus floor, (C) Placement of PRF plug, (D) Collagen membrane placed over osteotomy site, (E) Osteotome used to elevate collagen membrane, (F) Bone allograft placed into osteotomy site in increments, (G) Osteotomes elevate graft material, (H) Implant placement, (I) Final implant with graft material.• Favorable conditions:(>5mmhostbone,Implantsize<4mmgreaterthanhostbone)• Unfavorable conditions:(>8mmhostbone,Implantsize<4mmgreaterthanhostbone) • BOX 37.10 SA-3 (Crestal Approach) Requirements 1027CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgeryblowingthenose.Sneezing,ifitoccurs,shouldbedonewiththemouth open to relieve pressure within the sinus. Swelling of the region is common, but pain is usually less severe than after ante-riorimplantsinanedentulousmandible.Inaddition,thepatientshould be warned against lifting and pulling on the lip to observe the surgical site or during oral hygiene procedures to reduce the risk of incision line opening. e patient should be notied that small bone particles or synthetic bone found in the mouth or expelledfromthenosewithbleedingisnotunusual(Box37.12). Implant Insertione implant surgery at reentry after successful sinus grafts is simi-lartoSA-1,withafewexceptions.eperiostealaponthelat-eral side is elevated to directly allow inspection of the previous access window of the sinus graft. e previous access window may appear completely healed with bone, soft and lled with loose graftmaterial,orwithcone-shapedbroustissuein-growth(withthebaseoftheconetowardthelateralwall).ADE FBC• Fig. . SA-4. (A) Membrane elevation starting on the floor of the sinus. (B and C) Membrane is reflected to the medial wall. (D) First layer (superior) is collagen with antibiotic. (E) Second layer (middle) allograft bone. (F) Third layer (floor), which is comprised of autogenous bone.BA• Fig. . SA-4. Bone placement (A) placement with a 1-cc syringe. (B) Bone packer is used until “push-back” is obtained.• Favorable or unfavorable conditions:<5mmhostbone • BOX 37.11 SA-4 Requirements 1028PART VII Soft and Hard Tissue RehabilitationIfthegraftsiteonthelateral-accesswallappearsclinicallyasbone,then the implant osteotomy and placement follow the approach des-ignatedbythe bone density. Ifsofttissue has proliferated into theaccess window from the lateral-tissue region, then it is curetted and removed. e region is again packed to a rm consistency with autol-ogous bone from the previously augmented tuberosity and mineral-izedfreeze-driedbone.eimplantosteotomymaythenbepreparedandtheimplantplacedatheD4boneprotocol.Additionaltime(6monthsor more)is allowed until the stage II implant uncovery isperformed and progressive bone loading is used during prosthetic reconstruction.etimeintervalforstageIIuncoveryandprostheticprocedures after implant insertion of a sinus graft is dependent on the density of bone at the reentry of implant placement. e crest of theridgeandtheoriginalantraloormaybetheonlycorticalbonein the region for implant xation. e most common bone density observedforasinusgraftreentryisD3orD4.Mostoften,mineral-izedbonegraft(orxenograft)materialinthesinusgrafthasnotcon-vertedtobone.etactilesenseandtheCBCTevaluationinterpretthemineralizedgraftmaterialasadenserbonetype;thereforeatactileorradiographicD3bonemayactuallybeD4-likebone.Itisprudenttowaitlonger(ratherthanshorter)forimplantuncovery.AnSA-4sinusgrafthasarecommendedhealingtimeatleast4to6monthsforimplantinsertionandanother4to8monthsforimplantuncovery.ereforetheoverallgraftmaturitytimeis4to10monthsforSA-3,andSA-4healingtimeis8to14monthsbeforeprostheticreconstruc-tion.Progressiveloadingafteruncoveryismostimportantwhentheboneisparticularlysoftandlessdense.InadequateboneformationafterthesinusgrafthealingperiodofSA-4surgeryisapossible,butuncommon, complication. Intraoperative Complications Related to Sinus Graft SurgeryMembrane Perforationse most common complication during sinus graft surgery is tear-ingorcreationofanopeninginthesinusmembrane(Box37.13).is has several causes, which include a preexisting perforation, tearing during scoring of the lateral window, existing or previous pathologic condition, and elevation of the membrane from the bonywalls. Accordingto studies, membraneperforationsoccurabout10%to34%ofthetime.Ithasbeenreportedwithahigherfrequencyinsmokers.Ifmembraneperforationoccursmoreoftenthan this, then the clinician should give consideration to alter or reevaluate the surgical technique used in sinus grafting.Sinus membrane perforation usually does not aect the sinus graft.However,inareportoftheSinusConsensusConference,analysisoffailedsinusgraftsfound48%(79of164failures)wereattributed to sinus membrane perforations.130Inanendoscopicevaluation after sinus grafts, macrolaceration of the sinus mem-brane resulted in a typical sinusitis appearance, even when clini-cal conditions of infection were not present.132 Once the tear or perforation is identied, the continuation of the sinus elevation procedure is modied. e sinus membrane should be elevated othebonywallsoftheantrum,despitethemucosaltear.Ifaportion of the membrane is not elevated away from a sinus wall, then the graft material will be placed on top of the membrane, preventing the bone graft from incorporating with the bony wall.e perforation of the sinus membrane should be sealed to pre-vent contamination of the graft from the mucus and contents of the sinus proper and to prevent the graft material from extruding intothesinusproper.Whengraftmaterialsenterthesinusproper,they may become sources for infection or may migrate and close o the ostium to the nasal cavity and create an environment for an infection.Numerous studies have shown a very low probability of sinus infectionsafterperforationsinthesinusmembrane.Jensenandcolleagues133 reported that graft maturation occurred and no sinus infectionswereobserveddespitea35%incidenceofsinusperfora-tionduringtheprocedurein98patients.e surgical correction of a small perforation is initiated by elevating the sinus mucosal regions distal from the opening. Once the tissues are elevated away from the opening, the membrane ele-vation with a sinus curette should approach the tear from all sides so that the torn region may be elevated without increasing the openingsize.eantralmembraneelevationtechniquedecreasestheoverallsizeoftheantrum,thus“folding”themembraneoveron itself and resulting in closure of the perforation. A piece ofresorbablecollagenmembrane(e.g.,Collatape)isplacedovertheopening to ensure continuity of the sinus mucosa before the sinus bone graft is placed. e collagen will stick to the membrane and sealtheSAspacefromthesinusproper.Ifthesinusmembranetearislargerthan6mmandcannotbeclosed o with the circumelevation approach, then a resorbable collagenmembranewithalongerresorptioncycle(e.g.,Renovix,BioMend),maybeusedtosealtheopening.e remaining sinus mucosa is rst elevated as described pre-viously.Apieceofcollagenmatrixiscuttocoverthesinustearopeningandoverlapthemarginsmorethan5mm.Itshouldbenoted that when a sinus tear occurs, it is sealed with a dry col-lagen membrane so that it may be rotated into the lateral-access opening, gently lifted to the mucosal tissue around the opening, and allowed to stick to the mucosa. Once the opening is sealed, the sinus graft procedure may be completed in routine fashion. However, care should be taken when packing the sinus with graft material.Afteraperforation, the graft is easilypushedthroughthe collagen-sealed opening and into the sinus proper. e graft materialisthengentlyinsertedandpushedtowardthesinusoorandsidesbutnottowardthetopofthegraft.Asinusperforationmaycauseanincreasedriskofshort-termcomplications.Agreaterbacterial penetration risk exists into the graft material through 1. Donotblowyournose.2. Donotsmokeorusesmokelesstobacco.3. Donottakeinliquidsthroughastraw.4. Donotliftorpullonliptolookatsutures(stitches).5. Ifyoumustsneeze,thendosowithyourmouthopentoavoidanyunnecessarypressureonthesinusarea.6. Takeyourmedicationasdirected.7. Youmaybeawareofsmallgranulesinyourmouthfor2to3daysaftersurgery.8. Bleedingfromthenostrilmaybepresentfortherst24hoursaftersurgery. • BOX 37.12 Sinus Graft Postoperative Instructions• Small(<2mm)fast-resorbingcollagen(e.g.,Collatape,Oratape)• Medium(2–4mm)regularcollagen(e.g.,OraMem)• Large(>4mm)longeractingcollagen(e.g.,Renovix,OraMemExtend) • BOX 37.13 Membrane Perforations 1029CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgerythetornmembrane.Inaddition,mucusmayinvadethegraftandaect the amount of bone formation. Graft material may leak through the tear into the sinus proper, migrate to and through the ostium, and be eliminated through the nose or obstruct the ostium and prevent the normal sinus drainage. Ostium obstruc-tion is also possible from swelling of the membrane related to the surgery. ese conditions increase the risk of infection. However, despite these potential complications, the risk of the infection is low(lessthan5%);thereforethesinusgraftsurgeryshouldcon-tinue, and the patient should be monitored postoperatively for appropriatetreatment(Figs.37.49and37.50). Antral SeptaAntral septa (i.e., also termed buttresses, webs, and struts) arethe most common osseous anatomic variants seen in the maxil-lary sinus. Underwood,134 an anatomist, rst described maxillary sinusseptain1910.Hepostulatedthatthecauseofthesebonyprojections derived from three dierent periods of tooth develop-ment and eruption. Krennmair and colleagues135 further classied these structures into two groups: primary structures, which are a result of the development of the maxilla, and secondary struc-tures,whicharisefromthepneumatizationofthesinusooraftertooth loss.Misch136 postulated that septa might be bone reinforcement pillars from parafunction when the teeth were present. He noticed these structures occur more often in SA-3 sinuses and after ashorterhistoryoftoothloss.Long-termedentuloussitesandSA-4sinuses have fewer septa. e prevalence of septa has been reported tobein the range of33%ofthe maxillarysinuses in theden-tatepatientandashighas22%intheedentulouspatient.137 e septamaybecompleteorincompleteontheoor,dependingonwhether they divide the bottom of the sinus into compartments. e septa may also be incomplete from the lateral wall or, the medialwall,oritshouldextendfromtheoor.e shape of an incomplete maxillary sinus septum often resembles an inverted gothic arch that arises from the inferior or lateralwallsofthesinus.Inrareinstances,theymaydividethesinus into two compartments that radiate from the medial wall toward the lateral wall.e most common location of septa in the maxillary sinus has been reported to be in the middle (second bicuspid–rst molar)regionofthesinuscavity.CBCTscanstudieshaveshownthat41%of septa are seen in the middle region, followed by the posterior region (35%) and the anterior region (24%). For diagnosis andevaluationofsepta,CBCTscansarethemostaccuratemethodofradiographic evaluation.138Panoramicradiographyhasbeenshownto be very inaccurate, with a high incidence of faulty diagnoses.Sinusseptamaycreateaddeddicultyatthetimeofsurgery.Maxillaryseptacanpreventadequateaccessandvisualizationtothe sinus oor; therefore inadequate or incomplete sinus graft-ing is possible. ese dense projections complicate the surgery in severalways.Afterscoringthelateral-accesswindowintheusualfashion, the lateral-access window may not greenstick fracture and rotate into its medial position. e strut reinforcement is also more likely to tear the membrane during the releasing of the access window. e sinus membrane is often torn at the apex of the but-tress during sinus membrane manipulation because dicultyexists in elevating the membrane over the sharp edge of the web, and the curette easily tears the membrane at this position. How-ever, because septa are mainly composed of cortical bone, immedi-ate implant placement may engage this dense bone, allowing for strong intermediate xation. Moreover, septa allow for faster bone formation because they act as an additional wall of bone for blood vessels to grow into the graft.Management of Septa Based on LocationeuseofCBCTradiographsbeforesinusgraftsurgerypermitsthesurgeon to observe and plan the necessary modications to the sinus graft procedure as a result of the septa. e modication to the sur-gery is variable depending on its location. e septa may be in the anterior,middle,ordistalcompartmentoftheantrum.Whentheseptum is found in the anterior section, the lateral-access window is divided into sections: one in front of the septa and another distal to • Fig. . Maxillary sinus perforation from window outline osteotomy.AB• Fig. . Perforation repair. (A and B) Extended collagen membrane fixated on the superior aspect of the sinus cavity. 1030PART VII Soft and Hard Tissue Rehabilitationthe structure. is permits the release of each section of the lateral wall after tapping with a blunt instrument. e elevation of each released section permits investigation into the exact location of the septa and to continue the mucosal elevation.e mucosal tissue may often be elevated from the lateral walls above the septa. e curette may then slide down the side walls and release the mucosa from the bottom half of the sep-tum on each side. e sinus curette should then approach the crest of the buttress from both directions, up to its sharp apex. is permits elevation of the tissue over the web region without tearingthemembrane.Whenthestrutislocatedinthemiddleregion of the sinus, it is more dicult to make two separateaccess windows within the direct vision of the clinician. As aresult, one access window is made in front of the septa. e sinus curette then proceeds up the anterior aspect of the web, toward its apex. e curette then slides toward the lateral wall and above the septal apex. e curette may then slide over the crest of the septumapproximately1to2mm.Arm,pullingactionfrac-turestheapexoftheseptum.Repeatedsimilarcuretteactionscanfracturethewebotheoor.Oncetheseptumisseparatedotheoor,thecurettemayproceedmoredistalalongtheoorandwalls.When the septum is in the posterior compartmentofthesinus,itisoftendistaltothelastimplantsite.Whenthisoccurs, the posterior septum is treated as the posterior wall of the sinus. e sinus membrane manipulation and sinus graft are placed up against and anterior to the posterior septum (Figs. 37.51–37.53). BleedingBleedingfromthelateral-approachsinuselevationsurgeryisrare;however, it has the potential to be troublesome. ree main arte-rial vessels should be of concern with the lateral-approach sinus augmentation. Because of the intraosseous and extraosseous anas-tomoses that are formed by the infraorbital and posterior superior alveolar arteries, intraoperative bleeding complications of the lat-eral wall may occur. e soft tissue vertical-release incisions of the facialapinaresorbedmaxillamaysevertheextraosseousanas-tomoses. e extraosseous anastomosis on average is located 23 mmfromthecrestofthedentateridge;however,intheresorbedmaxilla,itmaybewithin10mmofthecrest.Whenthisarteryis severed, signicant bleeding has been observed. ese vessels originate from the maxillary artery and have no bony landmark to compress the vessel. erefore vertical release incisions in the soft tissueshouldbekepttoaminimumheightwithdelicatereec-tionoftheperiosteum.Hemostatsare usually dicult to placeonthefacialaptoarrestthebleeding.Signicantpressureattheposterior border of the maxilla and elevation of the head to reduce the blood pressure to the vessels usually stops this bleeding. e elevation of the head may reduce nasal mucosal blood ow by38%.139,140e vertical component of the lateral-access wall for the sinus graft often severs the intraosseous anastomoses of the posterior alveolar artery and infraorbital artery, which is on average approxi-mately15to20mmfromthecrestofadentateridge.Methodstolimit this bleeding, which is far less of a risk, have been addressed and include cauterization by the handpiece and diamond burwithout water, electrocautery, or pressure on a surgical sponge whiletheheadiselevated(Fig.37.54).e third artery of which the implant surgeon should be cau-tious is the posterior lateral nasal artery. is artery is a branch of the sphenopalatine artery that is located within the medial wall of theantrum.Asitcoursesanteriorly,itanastomoseswithterminalbranchesofthefacialarteryandethmoidalarteries.Asignicantbleeding complication may arise if this vessel is severed during elevation of the membrane o the thin medial wall.Epistaxis(activebleedingfromthenose)isacommondisorder;however,ithasbeenreportedthat6%ofpatientswhoexperiencethis in the general population require medical treatment to con-trolandstopthehemorrhagebecauseitlastslongerthan1hour.Treatment options to treat epitasis include nasal packing, electro-cautery,andtheuseofvasoconstrictivedrugs.Vesselligationand/or endoscopic surgery are necessary on rare occasions.e most common site (90%) of nasal bleeding is from aplexus of vessels at the anteroinferior aspect of the nasal septum andtheanteriornasalcavity(whichisanteriortothesinuscav-ityandwithintheanteriorprojectionofthenose).eposteriornasalcavity accounts for 5%to10%of epitasis eventsandisintheregionofthesinusgraft.Iftheorbitalwallofthesinusis perforated, or if an opening into the nares is already present from a previous event, then the sinus curette may enter the nares and cause bleeding. e arteries involved in this site are com-posed of branches of the sphenopalatine and descending pallia-tive arteries, which are branches of the internal maxillary artery. e posterior half of the inferior turbinate has a venous network calledtheWoodruplexus.Lavageofthenareswithwarmsalineandoxymetazolinedecongestantspraysprovidesexcellentvaso-constrictiveactivity to treatthe condition. A cotton roll withsilvernitrateorlidocainewith1:50,000epinephrinemayalsobe eective.Bleeding from the nose may also be observed after sinus graft surgery. Placing a cotton roll, coated with petroleum jelly withdentalosstiedtooneend,withinthenaresmayobtundnosebleedingafterthesurgery.After5minutesthedentalossisgentlypulled and removes the cotton roll. e head is also elevated, and iceisappliedtothebridgeofthenose.Ifbleedingcannotbecon-trolled, then reentry into the graft site and endoscopic ligation by anENTsurgeonmayberequired(Figs.37.55and37.56). Short-Term Postoperative ComplicationsShort-term complications are dened as those that occur within the rst few months after surgery.Incision Line OpeningIncision line opening is uncommon for this procedure becausethe crestal incision is in attached gingiva and usually is at least 5mmaway from the lateral-access window.Routinely, the softtissue requires release before primary approximation and sutur-ing. Because a collagen membrane is placed over the window, the soft tissue will usually not approximate without tension unless the surgeonexpandsthefacialapbyreleasingtheperiosteumabovethe mucogingival junction (where the tissue becomes thicker).Incisionlineopeningoccursmorecommonlywhenlateral-ridgeaugmentation is performed at the same time as sinus graft surgery, or when implants are placed above the residual crest and covered withthesofttissue.Itmayalsooccurwhenasofttissue–supportedprosthesis compresses the surgical area during function before suture removal.e consequences of incision line opening are delayed healing, leaking of the graft into the oral cavity, and increased risk of infec-tion. However, if the incision line failure is not related to a lateral onlay graft and is only on the crest of the ridge and away from the 1031AB CD EFGHIJK L• Fig. . Large septum in center of sinus. (a) Septum. (B) Window made anterior to septum. (C) Membrane is elevated off of floor. (D–G) Membrane is exposed anteriorly, posteriorly and to the medial wall. (H) Posterior window is outlined. (I–L) Membrane exposed on second window allowing for grafting around the septum. 1032PART VII Soft and Hard Tissue Rehabilitationsinus access window, then the posterior crestal area is allowed to healbysecondaryintention.Duringthistime,asofttissue–borneprosthesis should be aggressively relieved, with no reline mate-rial in contact with the ridge. If incision line opening includesa portion of a nonresorbable membrane (i.e., for lateral-ridgeaugmentation), then the membrane should be cleaned at leasttwice daily with an oral rinses of chlorhexidine. Nerve Impairmente infraorbital nerve is of concern in sinus elevation surgery because of its anatomic position. is nerve enters the orbit via the inferiororbitalssureandcontinuesanteriorly.Itliesinagrooveintheorbitaloor(whichisalsothemaxillarysinussuperiorwall)before exiting the infraorbital foramen. e infraorbital nerve exitstheforamenapproximately6.1to7.2mmfromtheorbitalrim. Note that anatomic variants have been reported to include dehiscence and malpositioned infraorbital foramina, along with the nerve transversing the lumen of the maxillary sinus rather thancoursingthroughthebonewithinthesinusceiling(orbitaloor).Malpositionednerveshavebeenreportedasfaras14mmfromtheorbitalriminsomeindividuals.Intheseverelyatrophicmaxilla, the infraorbital neurovascular structures exiting the fora-men may be close to the intraoral residual ridge and should be avoidedwhenperformingsinusgraftprocedurestominimizepos-sible nerve impairment. is is of particular concern on soft tissue reectionandthebonepreparationofthesuperioraspectofthewindow.Specialconsiderationsshouldbetakenduringreectionofthesuperiorap,andsharp-endedretractorsshouldbeavoided.Usually,thosemostatriskhaveasmallcranialbase(i.e.,elderlyfemales).ComplicationBecause the infraorbital nerve is responsible for sensory innerva-tions to the skin of the molar region between the inferior bor-der of the orbit and the upper lip, iatrogenic injury to this vital structure can result in signicant neurosensory decits of this ana-tomic area. Most often the nerve is not severed, and a neuropraxia results.Eventhoughthisinjuryissensoryandthereisnomotordecit,patientsusuallyhaveadiculttimeadaptingtothisneu-rosensoryimpairment(Fig.37.57). ManagementIfaninfraorbitalnerveimpairmentoccurs,theimplantclinicianshould immediately follow the clinical and pharmacologic neuro-sensory impairment protocol. A B• Fig. . Septum in posterior part of sinus. (A) Maxillary septum found on the floor in the posterior of the sinus. (B) An access window and curette elevates the mucosa anterior to the septum. The posterior septa is used as a posterior wall to contain the graft material.AB• Fig. . Clinical image of septum. (A) Two windows bisecting the sep-tum. (B) Both windows reflected exposing the septum. 1033CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryRevision SurgeryWhen failure or compromise of the sinus graft occurs, reentryprocedures are sometimes required to correct decits. Failed or compromised sinus grafts result in altered soft and hard tissue characteristics, mainly the formation of adhesions of the Schnei-derianmembranetothebuccalap.isresultsindicultywithreecting the buccal ap during the reentry procedure. Stud-ies have shown that separation of the adhesions from the sinus mucosaledto a 47% perforation rate. In addition,ithasbeenshown that altered characteristics of the Schneiderian membrane resultinanonexiblethickbroticmembrane.Insomecases,inwhichvoidsarepresentbuthavedicultaccess,regraftingproce-dures may need to be accomplished via a closed approach through the osteotomy site.101Treatment ImplicationsBecause of access issues, along with the higher perforation rate and brotic changes in the Schneiderian membrane, patients need to be informed of a higher postoperative complication rate involving questionablereentrybonegrowthandimplantsuccess.Ifreentryis necessary, usually bony adhesions and bony fenestrations of the lateral walls will be present.e combination of brotic changes of the Schneiderian membrane, increased chance of perforation, and altered sinus physiology lead to a high complication rate. e continuation of the sinus mucosa and oral mucosa make reentry revision sur-geryproblematicanddicult.iswillrequiretheseparationof the oral and sinus mucosa to gain access to the sinus proper (Fig.37.58). A B• Fig. . Intraosseous anastomosis. (A) Significant bleed from anastomosis (B) controlled by crushing bony area in which bleeding originated.AB• Fig. . Nasal bleeding. (A) Nasal bleeding immediately postop (B) usually may be controlled by gauze pressure packs. 1034PART VII Soft and Hard Tissue RehabilitationEdemaBecauseoftheextentoftissuereectionandmanipulation,sinusgraft surgery often results in signicant edema. e resultant post-operative swelling can adversely aect the incision line, leading to greater morbidity.Preventioneuseofgoodsurgicaltechniquethatinvolvescarefulreectionand retraction will decrease the amount of postoperative edema. e greater the surgery duration, the greater is the chance of edema.Cautionshouldbeusedtodecreasetheamountofsurgicaldurationandshouldnotexceedthepatient’stolerance.Tomini-mizeedema,corticosteroiduseisused 1day beforeand2 daysafter surgery. is short-term prophylactic steroid use will allow for adequate blood levels to combat edema, which usually will peakat48to72hours.Dexamethasoneistheidealdrugofchoicebecauseofitshighantiinammatorypotency. CryotherapyApplicationofanicepack,alongwithelevationoftheheadandlimited activity for 2 to 3 days, will help minimize the post-operative swelling. is cryotherapy will cause vasoconstriction ofthecapillaryvessels,reducingtheowofbloodandlymphandresultinginalowerdegreeofswelling.Iceorcolddressingsshouldonlybeusedfortherst24to48hours.After2to3days,heat(moist)maybeappliedtotheregiontoincreasebloodandlymphowtohelpcleartheareaoftheinammatoryconse-quences. is will also help reduce the possibility of ecchymosis that may result. EcchymosisSinus graft surgery also increases the possibility of bruising or ecchymosis.Becauseoftheextentofreection,bonepreparation,• Fig. . Bleeding control. Bleeding may be controlled by electrocautery.ACBV216.02mmV2• Fig. . Nerve impairment. (A) Infraorbital foramen anatomic variants that are close to the residual ridge. (B) V2 sensory impairment. (C) Special broad-based retractor which minimizes trauma to the infra-orbital nerve. 1035CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgeryand the highly vascular surgical area, ecchymosis will occur more often with this procedure compared with other implant related surgeries.Etiologye etiology of ecchymosis includes the following: blood vessels rupture → red blood cells die and release hemoglobin → macro-phages degrade hemoglobin via phagocytosis → production of bilirubin(bluish-red)→ bilirubin is broken down to hemosiderin (golden-brown). PreventionInmostcases,ecchymosiswillnotbeabletobecompletelypre-vented; however, the goal should be to minimize the extent ofbruising. Additionally, good surgical technique, shorter surgicalduration, the avoidance of anticoagulant analgesics, and postop-erative cryotherapy all aid in the control of this phenomenon. Patientsshouldalwaysbeinformedofthepossibilityofecchymo-sis. is is easily accomplished by having it be part of the postop-erativeinstructions(Fig.37.59). PainMinimal discomfort and pain is usually associated with sinus graft surgery. However, if narcotics are indicated, any analgesic combi-nation containing codeine, such as Tylenol 3, is prescribed post-operatively because codeine is a potent antitussive, and coughing may place additional pressure on the sinus membrane and intro-ducebacteriaintothegraft.epatientisinstructedtocough(ifnecessary)withthemouthopentominimizepossibleairpressurechanges within the sinus cavity. Oroantral FistulaeOroantral stulae may develop postoperatively, especially if the patient has a history of past sinus pathology or infection. Small oroantralstulae(<5mm)usuallywillclosespontaneouslyaftertreatment with systemic antibiotic drugs and daily rinses with chlorhexidine.However,largerstulae(>5mm)willnormallyrequire additional surgical intervention (Fig. 37.60). Largerstulaeareassociatedwithanepithelializedtract,whichistheresult of the fusion of the sinus membrane mucosa to the oral epithelium.Whenthisoccurs,patientswillmostlikelycomplainofuidsenteringthenasalcavityoneatingordrinking.Cautionshouldbeexercised inusingtheValsalvamaneuver (i.e., noseblowingtest)toconrmthepresenceofanoroantralstulaatthe time of surgery. e patient is asked to pinch their nostrils together to occlude the nose. e patient blows gently to see if air escapes into the oral cavity via the sinus. is is not recom-mended because this test may create an opening or make a small openinglarger.eValsalvamaneuvermaybeusedpostopera-tively to diagnose a suspected communication.ManagementClosureoforoantralstulaecanbeaccomplishedbyusingbroad-basedlingualorfaciallyrotatedaps(Figs.37.61and37.62).Buc-calapstoclosethestulamaybemoredicultafterasinusgraftbecauseofthelocationofthegraftsite.Inaddition,thebuccaltissueisverythin,androtatedorexpandedbuccalapsusuallyresultinlossofvestibulardepth.Beforetheinitiationoftheapdesign, the soft tissue around the stula is excised and the sinus oorcurettedtoensuredirectbonecontact.Atension-freerotatedAB• Fig. . Revision surgery. (A) Postoperative infections often result in the sinus and nasal epithelium being continuous, (B) Reentry into sinus requires incising the tissue to separate the oral and nasal epithelium.• Fig. . Postoperative edema and ecchymosis. One of the most common postoperative complications is edema and ecchymosis, which often may extend into the mandible and neck area. 1036PART VII Soft and Hard Tissue Rehabilitationapisthenmadeforcompletecoveringofthecommunication.Fororoantralclosureaftersinusgraftprocedures,alingualapisrecommendedbecause of the abundance of keratinized mucosawithanadequatebloodsupply.Flapdesignsincludeislandaps,“tongue-shaped”aps,orrotationalandadvancedaps,depend-ing on the size of the exposure. A key to closing the oroantralopeningisthedissectionofthebuccalaplateraltothestula.Anincisionthatextends15mmanteriorandposteriortothestulais of benet. e stula then has an elliptical incision on each side of the opening. e core of tissue and the stulous tract are excised.efacialapisunderminedandexpandedwellintothetissues of the cheek. e palatal aspect of the incision is adjacent to thetongue-shapedap.Placementoftheincisionforthepedicleapshouldbesplitthicknessandtakeintoaccountthelocationand depth of the greater palatine artery. Once the attached palatal pedicle graft is rotated to the lateral and attached to the facial ap,horizontalmattress suturesareplaced to inverttheap toachieveawatertightseal.Sutureswithhightensilestrength(Vic-ryl)shouldbeusedandallowedtoremaininplaceforatleast2weeks(Fig.37.63). Post-Operative InfectionWhenevaluatingpostsurgicalinfectiouscomplicationsaftersinusgraft procedures, the implant clinician must dierentiate the type, location, and etiology of the infectious episode. e infec-tion may originate within the graft site or may originate in the maxillary sinus proper. Itcould also be a combination of both(Table 37.2).Veryfewstudieshaveevaluatedthesedierentpro-cesses.Postsurgically,thereexistmanyreportswithvaryingresults(approximately0%–27%)ontheincidence ofinfectionleadingto acute rhinosinusitis.141Postoperativeinfectionsaftersinusgraftsurgery may result from the following:•  Acute rhinosinusitis: infection within the sinus proper•  Graft site: infection within the graft area•  Combination infection: from acute rhinosinusitis and graft siteGraft Site InfectionsEtiology of Graft Site Infectionegraftsitemaybecomeinfectedfrommanysources:(1)preex-istingsitebacteria,(2)bacterialcontaminationofthesurgicalsite,(3)graft material,(4) surgicaltechnique,(5) bacterialcontami-nation from acute rhinosinusitis, (6) lack of systemic and localprophylacticantibiotics,and(7)systemic,mediation,orlifestylefactors(Fig.37.64).Additionally,studieshaveshownadirectcorrelationbetweenan increased infection rate with simultaneous implant placement and with simultaneous ridge augmentation.One such study showed that simultaneous ridge grafting increasedtheinfectionratesignicantly(15.3%)versussinusgraft-ingalone (3%).142Mostoften,theinfection beginsmorethan1week after surgery, although it may begin as soon as 3 days later. Diagnosise most common sign of graft site infection is swelling, pain, dehiscence, or exudate near or including the grafting surgical site.Patientsmaycomplainofpoortasteandlossofgraftpar-ticlesintheirmouth.Incisionlineopeningisacommonsequa-lae with exudate discharge. Graft site infections usually occur within days to weeks of the surgery and are less common as a late infection.Initially,theinfectionmaystartasagraftsiteinfection(localizedtothegraft),whichthenleadstoanacutemaxillaryrhinosinusitis(Fig.37.65). TreatmentAlthough the incidence of infection after the procedureis usu-ally low, the damaging consequences on osteogenesis and the possibility of serious complications require that any infection be aggressivelytreated.Incaseofpostoperativeinfection,itisrecom-mended that the clinician perform a thorough examination of the area by palpation, percussion, and visual inspection to identify theareaprimarilyaected.Infectionwillusuallyfollowthepathof least resistance and is observed by changes in specic anatomic sites to which it spreads.143Early, aggressive treatment is crucial for graft site infectionsto prevent the loss of graft or extension of the infection into the sinus proper, causing an acute rhinosinusitis or spread of infec-tiontoothervitalareas.Initially,systemicantibioticsalongwithantimicrobialrinsesshouldbeused.Ifinfectionpersists,debride-ment and drainage should be completed, along with the use of sterile saline and chlorhexidine. A Penrose drain may also beusedincasesthatdonotrespondtosystemicantibiotics.Insomeinstances,oroantralstulaeresultafterinfectioncessation(seethesection“OroantralFistulae”).Antibiotictreatmentinthemaxillarysinus,bothprophylacti-cally and therapeutically, is much dierent than for most oral sur-gicalprocedures.Whenselectingantibioticmedicationsforsinusinfections, a variety of factors must be evaluated. ese include the most common type of pathogens involved, antimicrobial resis-tance, pharmacokinetic and pharmacodynamic properties, and AB• Fig. . Oroantral fistula: (A) Postoperative fistula resulting from poor wound healing. (B) Radiograph showing communication between the sinus and oral cavity. 1037CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryBACDE• Fig. . Oroantral fistula repair. (A) oroantral fistula, (B) flap extension for tension-free closure, (C) Extended collagen membrane, (D) Membrane positioned, (E) Lateral sliding flap to obtain primary closure. 1038PART VII Soft and Hard Tissue Rehabilitationthetissue(sinus)penetrationofthevariousantibioticdrugs.eantibiotic medication of choice should be eective against respira-tory and oral pathogens while exhibiting known activity against resistant strains of the common pathogens. Two such factors are usedwhenevaluatingsinusantibioticmedications:(1)themini-muminhibitoryconcentration(MIC)and(2)theconcentrationofantibioticdrugspenetratinginameddiseasedsinustissue.eMICisthelowestconcentrationoftheantimicrobialagentthatresultsintheinhibitionofgrowthofamicroorganism.eMICisusuallyexpressedbyMIC50orMIC90,meaningthat50%or90%ofthemicrobialisolatesareinhibited,respectively.Previ-ous studies and treatment modalities used amoxicillin as the rst drug of choice. However, with the increasing prevalence of peni-cillinase- and β-lactamase–producingstrainsofH. inuenzae and M. catarrhalis, along with penicillin-resistant strains of S. pneu-moniae, other alternative antibiotic drugs should be selected.β-Lactam Medications. e most common β-lactam antibi-otic drugs used in the treatment of rhinosinusitis and graft site infections are penicillin (amoxicillin, Augmentin) and cephalo-sporin(Ceftin,Vantin).Amoxicillinhasbeenthedrugofchoicefor years to combat the bacterial strains associated with rhinosi-nusitis and infections in the oral cavity. However, its eectiveness has been questioned recently because of the high percentage of β-lactamase–producingbacteria and penicillin-resistantS. pneu-moniae. Augmentin (amoxicillin-clavulanate) has the addedadvantage of activity against β-lactamase bacteria. It has beenassociated with a high incidence of gastrointestinal side eects. However,withthedosingregimen(twiceaday[bid]),thesecom-plications have been signicantly decreased. Two recommended cephalosporin medications have also been suggested to treat rhi-nosinusitis:cefuroximeaxetil(Ceftin)andcefpodoximeproxetil(Vantin).Othercephalosporindrugsfailtoachieveadequatesinusuid levels against the causative pathogens. Ceftin and Vantinhavegoodpotencyandecacy,while exhibitingstrongactivityagainst resistant S. pneumoniae and H. inuenzae. Macrolide Medications. Macrolide drugs are bacteriostatic agents that include erythromycin, clarithromycin (Biaxin), andazithromycin (Zithromax). Macrolide medications have goodactivity against susceptible pneumococci; however, with theincreasing rate of macrolide resistance, their use in combating sinus pathogens is becoming associated with a high likelihood of clinical failure. ese antibiotic drugs are very active against M. catarrhalis, although their activity on H. inuenzae is question-able. ese antibiotic medications are not suggested to treat post-operative sinus infections. Lincosamide Medications. Clindamycin (Cleocin) is theprimary lincosamide drug used in clinical practice today that is considered to be bacteriostatic. However, in high concen-trations, bactericidal activity may be present. Clindamycinis mainly used for the treatment of gram-positive aerobes and anaerobes. With acute sinus disease, clindamycin isusually not indicated because it exhibits no activity against ABC• Fig. . Membrane-assisted closure of oroantral communications. (A) Oroantral fistula in the right maxillary alveolar process in the region of the missing first molar, which is to be closed with subperiosteal placement of alloplastic material such as gold or titanium foil or a resorbable collagen membrane. Facial and palatal mucoperiosteal flaps are developed. Extension of the flaps along the gingival sulcus one or two teeth anterior and posterior allows some stretching of the flap to facilitate advancement for closure over the defect. The fistulous tract is excised. Osseous margins must be exposed 360 degrees around the bony defect to allow placement of the membrane beneath the mucoperiosteal flaps. The flap is sup-ported on all sides by underlying bone. (B) Closure. Ideally, the flaps can be approximated over the defect. In some cases, a small gap between the flaps will heal over the membrane by secondary intention. Even if the intraoral mucosa does not heal primarily, the sinus lining usually heals and closes, and the membrane is then exfoliated or resorbed, and mucosal healing progresses. (C) Cross-section of membrane closure technique. Buccal and palatal mucoperiosteal flaps are elevated to expose osseous defect and large area of underlying alveolar bone around the oroantral communication. The membrane overlaps all the margins of the defect, and the facial and palatal flaps are sutured over the membrane. (From Hupp JR, etal. Con-temporary Oral and Maxillofacial Surgery. 5th ed. St Louis, MO: Elsevier; 2009.) 1039CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryH. influenzae and M. catarrhalis. This drug may be used in chronic sinus conditions because anaerobic organisms play a much larger role in the disease process. Tetracycline-Derived Medications. Doxycycline (Vibramy-cin)isabacteriostaticagentwithadequateactivityagainstpeni-cillin-susceptible pneumococci and M. catarrhalis. is drug does not exhibit any activity against penicillin-resistant bacteria and is not eective against H. inuenzae. However, doxycycline may be used as an alternative antibiotic for the treatment of acute rhino-sinusitis infections. Sulfonamide Medications. e most common sulfonamide drug,trimethoprim-sulfamethoxazole(Bactrim)isbacteriostatic.Recently a high rate of resistance to these drugs has been seenwith S. pneumoniae, H. inuenzae, M. catarrhalis, and other sinus pathogens. is drug should not be considered to treat postopera-tive infections unless a culture and sensitivity test has been per-formed and susceptibility is shown. Metronidazole Medication. Metronidazoleisthemostimpor-tantmemberofthenitroimidazolegroup.Itisbactericidalandiseective against gram-positive and gram-negative anaerobic bac-teria.Itsmainusewouldbeinthetreatmentofchronicsinus(notacute)conditions.emedicationshouldbeusedwithanotherantibiotic drug to be eective against aerobic bacteria.Antibiotic Conclusion. In the evaluation of dierent antibi-otic drugs used for the treatment of pathologic conditions of the sinus, meticulous analysis of the activity against the most com-monpathogensmustbeevaluated.Withalloftheantibioticmed-ications evaluated, amoxicillin-clavulanate, and cefuroxime axetil A BC• Fig. . Postsinus graft infection. (A) Preoperative radiograph. (B) Postoperative sinus augmentation. (C) 4-week postop with graft site infection and acute rhinosinusitis. 1040PART VII Soft and Hard Tissue Rehabilitationshowexcellent MIC 90 blood levels against the most commonpathogens associated with sinus infections. Decongestant Medications. Recentrecommendationsinthemedicalliteraturestatethatnasaldecongestants(sympathomimeticdrugs)shouldnotbeusedexceptinseverecasesofcongestionandinfection. Nasal decongestants have been shown to impair blood ow,decreasingantibioticlevelstothesite.Additionally,itmaycause a rebound phenomenon and the development of rhinitis medicamentosa.isreboundphenomenonhasbeentheorizedtooccur as a negative feedback vasodilation after repeated introduc-tionsofthesympathomimetic(vasoconstricting)drug. Saline Rinses. Animportanttreatmentforthepatientwiththepresence of acute rhinosinusitis and graft infections is the use of salinerinseswithabulbsyringeorasqueezebottleinthenos-tril used to lavage the sinus through the ostium. e nasal saline rinse has a long history for treatment of sinonasal disease. Hyper-tonic and isotonic saline rinses have proven to be eective against chronic rhinosinusitis. ese techniques of nasal irrigation have been evaluated, with the best option of a positive-pressure irriga-tionusingasqueezebottlethatdeliversagentlestreamofsalinetothenasalcavity(NeilMed’sSinusRinse;NeilMedPharmaceu-ticalsInc.).esyringeorsqueezebottleshouldnotsealthenasal Types of Postoperative Sinus InfectionsAcute Rhinosinusitis Graft Site Infection CombinationEtiology • Preexistingpathology• Nonpatentostium• Anatomicvariants• Graftoverll• Postsurgeryphysiologicalteration• Spreadofinfectionfromgraftsite• Historyofchronicrhinosinusitis• Preexistingodontogenicorallergicrhinosinusitis• Preexistingpathology• Oralpathogencontamination• Untreatedperiodontitis• Perforation• Lackofasepsis• Longdurationsurgery• Simultaneousridgeaugmentation• Simultaneousimplantplacement• Lackofprophylacticmedication• Lackoflocalgraftantibiotics• Systemicdiseases,smoking/alcoholPrimarysitecouldbesinusproperorgraftsiteBacteria Aerobicgram-positivecocci(Streptococcus pneumoniae)Aerobicgram-negativerods(Haemophilus influenzae) (Staphylococcus epidermidis, Streptococcus viridans, Branhamella catarrhalis)Aerobicgram-positivecocci(S. viridans)Aerobicgram-positivecocci(Staphylococcus aureus)Aerobicgram-negativerods(Bacteroides)Aerobicgram-positivecocci(peptostreptococcus)AnycombinationofpathogensPrevention CBCT:ConrmationofostiumpatencyConrmationofnopathologyoranatomicvariantsProphylacticmedicationsProphylacticmedicationGoodsurgicaltechniqueAseptictechniqueShortsurgicaldurationNomembraneperforationAnycombinationofpreventivemea-suresSymptoms Mild:Facialpain/edemaCongestionNasaldrip/blockageCoughSevere:Signicantfacialpain/edemaFeverHeadacheProptosis/diplopiaMalaiseSitepain/edemaIncisionlineopeningExudateBadtasteBleedingIntraoralswellingAnycombinationofsymptomsIdeal antibi-oticβ-Lactam β-LactamLincosamideβ-LactamInitial treat-mentAntibiotic:1.Augmentin2.CeftinNasalsalineAntibiotic:1.Augmentin2.ClindamycinChlorhexidineAntibiotic:1.Augmentin2.CeftinNasalsaline/rinseSecondary treatmentReferral,especiallyifcerebral/ocularsymptoms Debridement/irrigationPossiblecultureDebridementPossiblecultureReferral,especiallyifcerebral/ocularsymptomsCBCT, Cone beam computerized tomography. TABLE 37. 2 1041CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgeryopening because this may force bacteria up toward the ethmoidal sinus.Instead,agentlelavagewithsterilesalinerinsesthesinusandushesoutthemucusandexudate.Ideally,theheadisplaceddown and forward so that the saline can reach the ostium in the superior and anterior portion of the sinus. e course of therapy should continue for at least 7 days.144AnotheroptionistheNetiPot,whichisverycommonamongchronicrhinosinusitispatients(Fig.37.66). Acute Rhinosinusitis InfectionsEtiology of Acute Rhinosinusitisere are two causes of acute maxillary rhinosinusitis after sinus graft surgery: (1) preexisting maxillary sinus pathology or (2)progression of sinus graft surgery to involve the maxillary sinus proper(Fig.37.67). DiagnosisMaxillary rhinosinusitis is a complication that arises when the patient postoperatively complains of any of the following symp-toms: (mild) headache, pain, or tenderness in the area of themaxillarysinus;rhinorrhea;or(severe)fever,headache,orocularsymptoms. Studies have supported the fact that patients who had predisposing factors for rhinosinusitis were more at risk of devel-oping postoperative transient rhinosinusitis.e wide range of reported percentages (3%–20%) may bethe resultof dierentmethodsused for diagnosis (i.e., clinical,radiographic,endoscopic).Casesofmaxillarysinusitisafterdentalimplant surgery have rarely been reported in the dental literature. However, recently in the medical literature, numerous cases of minor to severe complications after sinus surgery have been docu-mented.Althoughveryinfrequent,severeinfectionsmayleadtomore severe complications, such as orbital cellulitis, optic neuri-tis, cavernous sinus thrombosis, epidural and subdural infection, meningitis, cerebritis, blindness, osteomyelitis, and, although rare, brain abscess and death.145 TreatmentIf infection occurs postoperatively, treatment must be aggres-sive because of the possible complications that may arise to close anatomic structures. Systemic antibiotic therapy is the rst line oftreatment,alongwithcloseobservationofsymptoms.Recentmedical literature discourages the use of systemic decongestants and highly recommends the use of saline lavage and rinses. Sys-temic decongestants have been shown to impair site antibiotic delivery and also have a high degreeofreboundeect (rhinitismedicamentosa).Ifsymptomsarenotalleviatedwithantibioticanddeconges-tant medications, possible referral to the patient’s physician orENTiswarranted.Emergencyconsultationshouldbeconsideredif the patient complains of a severe headache that is not relieved by mild analgesics, as well as persistent or high fever, lethargy, visual impairment, or orbital swelling.e authors highly recommend that a professional association withanENTbeobtained.Becausethepossiblemorbidityoftheseinfections and causative pathogen is not easily determined, referral issometimesneeded.Additionally,ifmildsinussymptomsper-sist or signs of severe infection are present, immediate referral is recommended.Resolution of theseconditionshasbeenaccom-plished with the use of antibiotic drugs, endoscopic treatment, or Caldwell-Lucprocedures(Fig.37.68). Combination (Graft Site Infections/Acute Rhinosinusitis)Etiologye etiology of a combination infection can either be initiated from the graft site or the sinus proper. Diagnosise diagnosis for a combination type infection can parallel a com-binationofgraftsitesymptomsand/oracuterhinosinusitis. Treatmente treatment of a combination type infection should include the use of a β-lactamantibiotic(e.g.,Augmentin)followedbytheuseofdebridementandnasalsalinerinses.Ifocularorcerebralsymp-toms persist, or the patient does not respond to antibiotic treat-ment, referral is recommended.The most current, comprehensive study on the treatment of sinus disease involves guidelines established by the Sinus andAllergyHealthPartnership,CentersforDiseaseControlandPrevention,andtheFDAin2000.Withthisinformationas a guide, the following recommendations for antibiotic use in the treatment of infections after sinus graft are suggested (Box37.14). Spread of InfectionBecause of the anatomic and topographic location of the maxillary sinus, infections from oral or sinus pathogens may spread quickly to adjacent sites.Sinus-related pathologic conditions are the most common causeoforbitalinfection,accountingfor60%to84%ofcases.Because of the seriousness of ocular infections, early diagnosis and aggressive treatment is paramount.Variousroutesmaypredisposethisareatoinfectionfromthemaxillary sinus and include the following:1. evenousplexusofthemaxillarysinusdrainsthroughtheposterior wall into the deep facial vein, through the pterygoid plexus, and nally into the cavernous sinus.2. Veins also perforate the osseous roof of the maxillary sinus,entering the orbit through the superior and inferior ophthal-mic vein. ese veins also are connected to the pterygoid plexus and cavernous sinus.• Fig. . Graft site infection showing exudate and incision line opening. 1042PART VII Soft and Hard Tissue RehabilitationABCDE• Fig. . Postgraft infection. (A) Cone beam computerized tomographic (CBCT) coronal image show-ing implant with associated infection. (B) Axial CBCT image showing a completely opacified sinus. (C) Intraoral view of draining fistula tracts (green arrows). (D) Incision and drainage. (E) Exudate and infected tissue removal. 1043CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgery3. Additionally,numerousveinsperforatetheanteriorwallthatdrain into the superior ophthalmic vein and into the cavernous sinus. From the cavernous sinus, drainage through the deep middle cerebral vein communicates with the white substance ofthebrain’ssupercialvenoussystem.Because of the elaborate maxillocerebral venous anastomo-ses, spread of infection from the maxillary sinus may result in possible sequelae such as brain abscesses, intraorbital abscesses, orbital cellulitis, cavernous sinus thrombosis, and osteomyelitis. Implant Penetration Into the SinusBränemark and colleagues146 reported on animal histologic stud-ies and 44 clinical cases of implants penetrating the maxillarysinus. ey reported success rates comparable to other maxillary implants, and no postoperative signs or symptoms were found withtheseimplants.AnanimalstudybyBoyne147 led to the same conclusion. e assumption was that direct connection between hard and soft tissues to the integrated implant created a barrier to the migration of microorganisms. However, it should be noted these animals do not have the same incidence of maxillary sinusitis comparable to humans.Itis possible that an implant that penetrates the sinus oormay contribute to a source of periodic sinusitis because a bacterial • Fig. . Neti Pot. Used for nasal irrigation resulting in flushing out the nasal passages.AB• Fig. . Culture and sensitivity. In some cases of rhinosinusitis, a cul-ture and sensitivity test may be administered. (A) Swab sealed and sent to laboratory for culture and sensitivity testing.(B) Culture swab placed into the infected site.AB• Fig. . Functional endoscopic sinus surgery (FESS). (A) FESS scope. (B) Surgical placement of FESS. 1044PART VII Soft and Hard Tissue Rehabilitationsmearlayerwouldbediculttoremovethroughregularphago-cyticactivity.Whenthisissuspected,removaloftheimplantoran apicoectomy of the implant apex, from a lateral-access window, maybeofbenet(Fig.37.69). Overfilling of the Sinusegoalofthesinusgraftistoobtainsucientverticalheightof bone to place endosteal implants with long-term success. e maximum length requirement of an implant with adequate sur-faceofdesignisrarelymorethan15mm,andasaresult,thegoaloftheinitialsinusgraftistoobtainatleast16mmofverticalbone from the crest of the ridge. is usually means the bot-tom one-half of the sinus is lled with graft material because mostsinusesapproximate35mminheight.ACBCTscanofthe sinus before surgery may be used to estimate the amount of graft material required for the ideal volume of sinus graft mate-rial.Careshouldbegiventotheamountofgraftmaterialplacedinto the sinus. Overlling the sinus can result in blockage of the ostium,especiallyifmembraneinammationorthepresenceofa thickened sinus mucosa exists.e majority of sinus graft overlls do not have postopera-tivecomplications.If,however,apostoperativesinusinfectionoccurs without initial resolution, reentry and removal of a por-tion of the graft and changing the antibiotic protocol may be appropriate(Fig.37.70). Postoperative Cone Beam Computerized Tomographic Mucosal Thickening (False Positive for Infection)Immediatepostoperativeradiographsmayrevealsignicantmuco-sal thickening within the sinus. e clinician should not determine this to be infection unless the previously mentioned signs of infec-tion are noted. Normally, elevation of the sinus mucosa and bone grafting does alter the overall maxillary sinus environment by reduc-ingthesizeofthesinusandrepositioningthemucociliarytransportsystem.Inspiteofthis,onlyshort-termclearanceimpairmentexists,resulting in only subclinical eects on the sinus physiology. How-ever, in cases of preoperative sinusitis histories, elevation surgery maypredisposeapatienttosinus-relatedcomplications.Ithasbeenshown that these procedures do alter the microbial environment. Studies reveal at 3 months after surgery, positive sinus cultures were present compared with cultures taken for the same patients pre-operatively.However,after 9monthstheculturesweresimilartothe preelevation results. e key is maintenance of the ostiomeatal opening between the maxillary sinus and the nasal cavity. Migration of ImplantsIn1995therstcaseofadisplaced(migrated)implantintothemaxillary sinus was documented. Since then, an increased number of reports are coming to light, documenting an ever-increasing problem.Reportshaveshownthatimplantsmigratingfromthemaxillary sinus have been found in the sphenoid sinus, ethmoid sinus, orbit, nasal cavity, and anterior cranial base.Etiologye etiology of implant displacement or migration from the maxillary sinus includes many possibilities. e timing of • Fig. . Implant penetration into sinus. Coronal image showing implant placement into maxillary sinus leading to a completely opacified maxillary sinus.Mild InfectionSymptoms• Purulentandnonpurulentnasaldrip• Nasalblockage • Facialpainandpressure • Intraoralandextraoralswelling• Cough Treatment1. Amoxicillin-clavulanate(Augmentin)825mg/125mg(1tabletbidfor10days) a. Ifnonanaphylacticallergytoamoxicillin:cefuroximeaxetil(500mg)1tabletbidfor10days b. Trueanaphylacticallergytoamoxicillin:doxycycline(100mg)1tabletbidfor10days2. Nasalsalinerinses Moderate to Severe InfectionSymptoms• Mildinfectionssymptoms• Severeheadache• Highpersistentfever(>102.5°F) • Periorbitalswelling • Ocularsymptoms(diplopia,proptosis) • Alteredmentalstatus• Infraorbitalhyperesthesia Treatment1. Immediatephysicianreferral(emergencyroomorENTPhysician)Bid, Twice daily; ENT, ear, nose, and throat (physician). • BOX 37.14 Infection Treatment Summary (Combination) 1045CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft Surgeryimplants ending up in the maxillary sinus proper varies from intraoperative displacement to migration years later. Many etio-logicfactorshavebeensuggested,accordingtothetiming(earlyversuslate)(Table 37.3). PreventionForearlymigration/displacementcomplications,mostlikelythecause is surgical error or incorrect treatment planning. Whenevaluatinglatemigration/placementcomplications,themajorityofissuesareadirectresultofpostoperativeprostheticerrors(tooearlyloading)orfactorsthatareprecipitatedbylackofintegrationor minimal bone at the implant interface. Managemente management of displaced or migrated implants into the max-illary sinus should be treated with urgency. Leaving implants in the maxillary sinus may lead to acute rhinosinusitis complications. Additionally,implantsleftinthemaxillarymaybecomecalcied(antrolith)orbecomedisplaced intoother anatomicareas(e.g.,sinuses,orbit,nasalcavity,brain).e patients should be referred as soon as possible for removal viaaCaldwell-Lucapproachorendoscopy(functionalendoscopicsinussurgery[FESS])(Figs.37.71–37.77). Postoperative Fungal InfectionFungalinfectionaftersinusbonegraftingisrarelyreported;how-ever, with the increased number of sinus graft procedures being performed, inevitably more will be reported in the literature. Fun-gal sinusitis is a destructive, invasive disease that is mostly caused by Aspergillus. Aspergillusspp.isafungusoftheAscomycetesclass,which is one of the most commonly encountered in the human environment.Inthediagnosisoffungalsinusitis,thereexisttwoforms: noninvasive and invasive. e invasive form is rare and is almost always associated with immunocompromised patients. Erosionandosseousdestructionoccursthatmaybefatal.How-ever, this form has not been associated with dental implants or sinus graft surgery.Case studies have shown postoperative complications aftersinus graft surgery148 and overextension of root canal lling involving the noninvasive form. is type of fungus growth is also termed fungus balls or aspergilloma and is associated with immu-nocompetent patients.DiagnosisUsually, the patient will present with clinical symptoms of frontal headache, orbicular pain, nasal congestion, and bleeding, with signs of chronic rhinosinusitis. Radiographically, a distinctly increasedsofttissuedensitymass(radiopacity)isseenonCBCTscans. ManagementReferraltoanENTforevaluationandconrmationofdiagnosis.Usually, treatment involves surgical removal via Caldwell-Luc orFESStechniquesbecausesystemicantimycoticdrugsareineective. SummaryInthepast,implanttreatmentintheposteriormaxillawasreportedastheleastpredictableregionforimplantsurvival.Causescitedinclude inadequate bone height, poor bone density, and high occlusalforces.Past implant modalitiesattemptedto avoid thisregion, with procedures such as excessive cantilevers from anterior implants or excess numbers of pontics when implants are placed anterior and posterior to the antrum.AB• Fig. . Overfilling of the sinus. (A) Cone beam computerized tomographic coronal scan image depict-ing excess graft material occluding the maxillary ostium. (B) Significant overfill of maxillary sinus leading to an acute rhinosinusitis. Migration of Dental ImplantsEarly Late• Poorinitialstability• Overpreparationofosteotomysite• Poorqualityofbone• Nocrestalcorticalbone• Implantplacementintosinuswithoutbonegraft• Incorrecttreatmentplanning• Surgicalinexperience• Untreatedantralpreparation• Postoperativesinusinfection• Immediateplacementimplants• Tooearlyloading• Changesinintranasalorintrasinuspressure• Peri-implantitis• Autoimmunereaction TABLE 37. 3 1046PART VII Soft and Hard Tissue Rehabilitatione maxillary sinus may be elevated and SA bone regener-ated to improve available bone height. Tatum began to develop thesetechniquesasearlyasthemid-1970s.3 Misch149 developed fouroptionsfortreatmentoftheposteriormaxillain1984basedontheheightofbonebetweentheooroftheantrumandthecrest of the residual bone. ese options were further modied toreectthewidthofavailablebone,onceadequateheightwasobtained. Root-form implants of adequate size are indicated inthe posterior maxilla. e higher forces and less dense bone often require larger diameter implants.Itistheobservationoftheauthors,usingthesinusgraftpro-ceduresdescribedinthischapterformorethan30years,inclini-cal practice, universities, and private implant institutes, that the sinus graft procedure is more than 97% eective. is regionof the mouth predictably grows more bone in height than any otherintraoralregion.However,anorganizedapproachneedstobe completed with respect to patient selection, pathology evalu-ation, pharmacologic management, and surgical and prosthetic protocol to increase success and decrease potential morbidity of the procedures.ABC• Fig. . Migrated implants into maxillary sinus. (A and B) Implants displaced into maxillary sinus. (C) Implant obstructing the maxillary ostium.• Fig. . Migrated implant into nasal cavity. Implant that was displaced into the maxillary sinus and eventually eroded through the medial wall of sinus into the nasal cavity. 1047CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryABCD• Fig. . Migrated implants. (A) Ethmoid sinus. (B–D) Migrated implant into sphenoid sinus. (A, From Haben M, Balys R, Frenkiel S. Dental implant migration into the ethmoid sinus. J Otolaryngol. 2003;32:342–344, 2003; B–D, From Felisati G, Lozza P, Chiapasco M, etal. Endoscopic removal of an unusual foreign body in the sphenoid sinus: an oral implant. Clin Oral Implants Res. 2007;18:776–780.) 1048PART VII Soft and Hard Tissue RehabilitationAB• Fig. . (A and B) Migrated implants into the orbital area. (From Griffa A, Viterbo S, Boffano P. Endoscopic-assisted removal of an intraorbital dislocated dental implant. Clin Oral Implants Res. 2010;21:778–780.)• Fig. . Migrated implants anterior cranial base. (From Cascone P, etal. A dental implant in the anterior cranial fossae. Int J Oral Maxillofac Surg. 2010;39:92–93.) 1049CHAPTER 37 Maxillary Sinus Anatomy, Pathology, and Graft SurgeryAB• Fig. . Etiology of displaced/migrated implants. (A) Implant placement into maxillary sinus without bone grafting. (B) Implant placement into sites with poor bone density, therefore compromised primary stability.ACDB• Fig. . (A) Panoramic radiograph depicting migrated dental implant in the right sinus. (B) Coronal image showing implant in the maxillary ostium area. (C) Functional endoscopic sinus surgery (FESS) approach to retrieve implant. (D) Removal of implant from sinus cavity. (From Chiapasco M, Felisati G, Maccari A, etal. The management of complications following displacement of oral implants in the para-nasal sinuses: a multicenter clinical report and proposed treatment protocols. 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