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Pediatric Airway Abnormalities

Pediatric Airway Abnormalities







Oral and Maxillofacial Surgery Clinics, 2012-08-01, Volume 24, Issue 3, Pages 325-336, Copyright © 2012 Elsevier Inc.


Sleep disordered breathing syndromes in pediatric patients can lead to adverse effects in the cardiovascular system, neurocognitive function, growth, and behavior. These syndromes occur more frequently in patients with craniofacial disorders. A high index of suspicion as well as early recognition, detection, and treatment of these syndromes are considered integral to care of children with craniofacial disorders.

Key Points

  • Sleep-disordered breathing occurs more frequently in patients with craniofacial disorders.

  • The associated hypoxia, hypercapnia, and bradycardia associated with sleep-disordered breathing syndromes can lead to adverse effects on daytime behavior, the cardiovascular system, neurocognitive function, and growth.

  • A high index of suspicion, early recognition, and detection of sleep-disordered breathing lead to more effective treatment and are considered integral to the care of all children with craniofacial disorders.

  • Nocturnal signs and symptoms of sleep-disordered breathing include heavy snoring, restlessness, increased respiratory effort, posturing or positioning, and intermittent apneas or pauses in breathing.

  • Airway complaints in wake and sleep of patients with craniofacial disorders should be assessed as part of their initial clinical evaluation.

  • The use of formal sleep studies (polysomnography) is advocated in suspected cases of sleep-disordered breathing in children with craniofacial disorders.

  • Airway obstruction is recognized as a common sequela of surgery to correct craniofacial disorders.


Introduction

The anatomy of the upper airway bears important influence on airflow and breathing cycles. The structures may limit the movement of air and also influence the dynamics of the regulation of airway reflexes and muscular tone. Many of these issues change with state. The state of sleep, in particular, is a time period in which airflow may be more disrupted, suggesting airway dysfunction. Sleep-disordered breathing (SDB) syndromes are typically divided into those related to hypoventilation and those changing the respiratory pattern, such as apnea. Apneas are typically classified as obstructive, central, and mixed. These pauses or interruptions of breathing are commonly recognized in children with cleft lip and cleft palate (CP) and other craniofacial syndromes, with an increased incidence noted in the literature. Observed cessation of airflow at the level of the nose or mouth, whether there is partial or complete obstruction, makes continued respiratory effort against a collapsed upper airway futile. Therefore, apneas are frequently associated with poor and fragmented sleep as well as arousals. The associated hypoxia, hypercapnia, and bradycardia can all lead to possible adverse effects on the child's daytime behavior, cardiovascular system, neurocognitive function, and growth. With the possible detrimental effects of obstructive events on children, early recognition and detection lead to more effective treatment and are considered integral in any craniofacial practice.


Anatomic and physiologic considerations

The airway can be divided into levels, beginning at the superiorly positioned area of the nose and nasopharynx, which communicate inferiorly with the oropharynx and descending into the laryngopharynx. At the level of the nose, the external and internal nasal valves are the main areas thought to provide resistance to flow. The nasal turbinates then direct flow, whether laminar or turbulent, with hypertrophy of the turbinates leading to obstruction. The upper airway is capable of collapse, and its patency is determined by its diameter; the tonic activity of muscular dilators, such as the genioglossus and tensor veli palatini; and the response to negative airway pressure generated during inspiration. During sleep, reduced tone of these dilators can lead to physiologic airway narrowing, which can result in SDB. Other physiologic effects are noted as well during the apnea. Progressive increases in the drive to breathe can lead to maximal respiratory efforts against a closed airway resulting in respiratory-related decreases in blood pressure due to progressively greater negative intrathoracic pressures. The apnea is terminated by an arousal followed by a return to a deeper sleep state with normalization of blood gases. Subsequently, the airway tone becomes reduced again and the obstructive cycle begins anew ( Fig. 1 ).

Sagittal cross section of head and neck illustrating airway anatomy.
Fig. 1
Sagittal cross section of head and neck illustrating airway anatomy.

Nasal obstruction secondary to arrhinia, pyriform aperture stenosis, septal deviation, and choanal atresia can contribute to SDB because of the increased nasal resistance to airflow, which often necessitates mouth opening and tongue retropulsion leading to further airway obstruction, narrowing, and collapse ( Fig. 2 ).

Axial computed tomography illustrating ( A ) normal neonatal nose, ( B ) pyriform aperture stenosis, ( C ) central mega-incisor with pyriform aperture stenosis, and ( D ) choanal atresia.
Fig. 2
Axial computed tomography illustrating (
A ) normal neonatal nose, (
B ) pyriform aperture stenosis, (
C ) central mega-incisor with pyriform aperture stenosis, and (
D ) choanal atresia.

The clinical spectrum of SDB ranges from benign primary snoring to obstructive sleep apnea syndrome (OSAS) as the most severe. The severity of the obstructions and age of presentation are often related to the degree and location of obstruction within the respiratory tract. These factors influence the severity of SDB with which a child clinically presents ( Table 1 ).

Table 1
Age-associated findings in SDB and suggested therapies
Age Sleep Findings Airway Findings Pulmonary Findings Therapy
Infants Obstructive and central apneas, hypoxemia Micrognathia, glossoptosis, cleft palate, retrognathia Inspiratory stridor, retractions, pectus excavatum Nasopharyngeal airway, CPAP, surgery, oxygen therapy
Early childhood Obstructive and central apnea Micrognathia, glossoptosis, cleft palate, retrognathia, pharyngeal restriction, adenoid and tonsillar hypertrophy Inspiratory stridor, retractions, pectus excavatum Surgery, CPAP
Late childhood Obstructive apnea Tonsillar hypertrophy Surgery, CPAP
Adolescence and adulthood Obstructive apnea and hypoventilation Tonsillar hypertrophy Surgery, CPAP
Abbreviation: CPAP, continuous positive airway pressure.

The major craniofacial abnormalities associated with airway obstruction include those involving the cranium and midface (craniofacial dysostosis syndromes), those primarily involving the mandible (Nager syndrome, Stickler syndrome, and Pierre Robin sequence [PRS]), and those involving a combination of the midface and mandible (Treacher Collins syndrome, oculoauriculovertebral syndrome, and craniofacial microsomia). Midface bony abnormalities are often accompanied by nasopharyngeal narrowing and oropharyngeal musculature crowding causing obstruction. In patients with mandibular abnormalities, the tongue is retropositioned, which leads to airway narrowing and obstruction ( Fig. 3 ).

Direct laryngoscopy with intubating laryngoscope illustrating ( A ) normal grade I view of larynx, ( B ) grade IV view of larynx in neonate with PRS and tongue-based airway obstruction; only the posterior pharyngeal wall and nasogastric tube are visible, and ( C ) flexible nasopharyngolaryngoscopic view of tongue base obstruction resulting from micrognathia.
Fig. 3
Direct laryngoscopy with intubating laryngoscope illustrating (
A ) normal grade I view of larynx, (
B ) grade IV view of larynx in neonate with PRS and tongue-based airway obstruction; only the posterior pharyngeal wall and nasogastric tube are visible, and (
C ) flexible nasopharyngolaryngoscopic view of tongue base obstruction resulting from micrognathia.

Enlargement of the tongue itself can also lead to airway obstruction. Beckwith-Wiedemann syndrome is a congenital disorder characterized by a unique group of physical examination findings; macroglossia is the most notable finding in the head and neck. These children can have SDB from their tongue musculature collapsing and retropulsing as well as obstruction from adenotonsillar hypertrophy necessitating surgical intervention if obstructive sleep apnea (OSA) is confirmed. In the setting of macroglossia, the differential diagnosis should also include trisomy 21, the mucopolysaccharidoses, hypothyroidism, and vascular malformations as well as tumors involving the tongue. Other less common conditions with macroglossia include hemihypertrophy syndrome, rhabdomyoma, dermoid cysts, and amyloidosis.

In the child with a cleft lip and/or palate (CL/P), both anatomic and functional changes increase the risk of SDB. Cephalometric analysis of human facial skeletal morphology associated with orofacial clefting (OFC) reveals reduced midfacial and mandibular projection and development, resulting in decreased size of the pharyngeal airway. The abnormal craniofacial relationships associated with OFC have been shown to persist beyond the period of skeletal growth. In particular, adults with a history of bilateral CL/P reveal smaller mandibular dimensions, larger vertical craniofacial dimensions, a smaller depth of the oropharynx, and an inferiorly positioned hyoid. All of these anatomic aberrancies predispose to SDB.

Patients with bilateral CL/P have greater impairment of nasal airway caliber compared with those with unilateral CL/P or with CP alone. Secondary palatal clefts affect the oropharyngeal musculature, with disruption resulting in abnormal airway function in addition to structural changes. The role of palatal muscle function on airway patency in the setting of CP has been reported in adult patients showing palatal musculature fulfilling an important role in maintaining the airway patency.

Several studies have supported an increased incidence of SDB amongst children with CL/P, including Muntz and colleagues who found symptoms of SDB in 22% of children in a retrospective review of all children presenting to a tertiary cleft and craniofacial team. MacLean and colleagues have provided evidence to support the underrecognition of OSAS in children with CL/P. These studies reveal an estimated risk of SDB in children with CL/P ranging between 22% and 65%, with 28% likely to have severe SDB. The prevalence of SDB is greater in the subgroup of infants and children with syndromes as well as those with PRS.


Clinical presentation and diagnosis

Nocturnal signs and symptoms of OSAS usually include heavy snoring, restlessness, increased respiratory effort, posturing or positioning, and intermittent apneas or pauses. Daytime signs and symptoms include nasal obstruction, hyponasal speech, mouth breathing, hyperactivity, and impaired memory and cognitive function. The symptoms of social withdrawal, hypersomnolence, and poor academic performance have also been reported. Other clinical signs and symptoms include intracranial hypertension, poor growth, failure to thrive, and cardiorespiratory complications, including arrhythmias, pulmonary hypertension, cor pulmonale, and the possibility of sudden death.

The attention capacity and cognitive ability of children are adversely affected by SDB. The ability to remain on task and attend to external stimuli play an important role in learning as well as social and academic development. The data suggest poorer sustained attention and more impulsive behavior with dose-dependent effects of SDB on memory capacity, suggesting that the more severe the SDB is, the poorer the child's performance will be. Some studies show these effects to be reversible with successful treatment of the upper airway obstruction. Caregivers' abilities to corroborate the above-mentioned symptoms are integral in the diagnosis of SDB, hence validated questionnaires at the time of the child's visit are used as screening tools, with positive correlative results in the diagnosis of OSAS.

The diagnosis of SDB in children is based on a combination of history from the caregivers, findings on physical examination, and possible adjunctive investigations. Examination should document craniofacial morphology, patency of nasal airways, septal deviation, status of the palate and adenoids, and size or grade of tonsillar hypertrophy ( Fig. 4 ).

Grading system for tonsillar hypertrophy. ( A ) no tonsil tissue present; ( B ) 1+; ( C ) 2+; ( D ) 3+; ( E ) 4+.
Fig. 4
Grading system for tonsillar hypertrophy. (
A ) no tonsil tissue present; (
B ) 1+; (
C ) 2+; (
D ) 3+; (
E ) 4+.

In addition, attention should be paid to the child's location on standardized growth charts, as well as signs of cardiorespiratory complications. Adjunctive investigations could include lateral cephalograms, electrocardiograms, chest radiographs, and echocardiograms.

One means of diagnosis commonly used is home pulse oximetry. Arguments against the use of oximetry alone, which only measures oxygen saturation and pulse rate, are primarily because of the limited scope of measurement and inability to document arousals, which makes it an unreliable tool in the investigation of SDB because many patients with significant upper airway obstruction who readily arouse may be missed. Further criticism classifies oximetry as a limited sleep study in which respiratory effort, snoring, hypercapnia, and sleep fragmentation are inadequately assessed. Although the positive predictive value of observed desaturations and hypoxemia during sleep is clinically significant, the absence of desaturations cannot be used to exclude OSAS. Other options include the use of home apnea monitors, which in the setting of young patients can be quite cumbersome for parents to configure and obtain accurate results whereas in the adult population this option has been shown to be effective.

The use of formal sleep studies (polysomnography [PSG]) is advocated to evaluate the function of the airway in suspected cases of SDB in children with craniofacial abnormalities; however, not all PSG studies are alike. Most sleep studies include only temperature sensors to measure airflow. This technique has been found to be insensitive for detecting hypopneas. The American Academy of Sleep Medicine 2007 guidelines outline the importance of studies including continuous nasal pressure measurements for accurate determination of hypopneas and respiratory effort–related arousals, especially in children. The American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) recent task force assembly development panel concluded with 5 evidence-based action statements with the indications for PSG in SDB listed in Table 2 . The guidelines were admittedly limited and do not apply to children younger than 2 years, older than 18 years, to those who have already undergone tonsillectomy, to children having adenoidectomy alone, to children being considered for continuous positive airway pressure (CPAP) therapy, and to children being considered for surgical therapy other than tonsillectomy for SDB. Statements in the AAO-HNS guidelines are not intended to limit or restrict care provided by clinicians, and decisions should be based on the assessment of individual patients.

Table 2
AAO-HNS guidelines and indications for PSG
Modified from Roland PS, Rosenfeld RM, Brooks U, et al. Clinical practice guideline: polysomnography for sleep-disordered breathing prior to tonsillectomy in children. Otolaryngol Head Neck Surg 2011;145(Suppl 1):S1–15; with permission.
Summary of Action Statements for PSG
Statement Action Evidence Purpose
1. Indications for PSG Before performing tonsillectomy, the clinician should refer children with SDB for PSG if they exhibit any of the following: obesity, Down syndrome, craniofacial abnormalities, neuromuscular disorders, sickle cell disease, or mucopolysaccharidoses Recommendation based on observational studies with a preponderance of benefit over harm Improve diagnostic accuracy in high-risk patients and define severity of OSA to optimize perioperative treatment planning, to improve quality of life and aid in clinical treatment plans
2. Advocating for PSG The clinician should advocate for PSG before tonsillectomy for SDB in children without any of the comorbidities listed in statement 1 for whom the need for surgery is uncertain or when there is discordance between tonsillar size on physical examination and the reported severity of SDB Recommendation based on observational and case control studies with a preponderance of benefit over harm Helps clinicians to encourage the use of PSG in children without any of the comorbid conditions in statement 1
3. Communication with anesthesiologist Clinician should communicate PSG results to the anesthesiologist before induction of anesthesia for tonsillectomy in a child with SDB Recommendation based on observational studies with a preponderance of benefit over harm Permit early identification of a child who may require preoperative optimization and a modified approach to anesthetic management and postoperative care
4. Inpatient admission for children with OSA documented in the results of PSG Clinician should admit children with OSA documented in results of PSG for inpatient, overnight monitoring after tonsillectomy if they are younger than 3 y or have severe OSA (apnea-hypopnea index of 10 or more obstructive events/hour, oxygen saturation nadir less than 80%, or both) Recommendation based on observational studies with a preponderance of benefit over harm Promote an appropriate monitored setting for children at potential risk for postoperative respiratory compromise that could necessitate medical intervention
5. Unattended PSG with portable monitoring device In children for whom PSG is indicated to assess SDB before tonsillectomy, clinician should obtain laboratory-based PSG when available Recommendation based on diagnostic studies with limitations and a preponderance of benefit over harm Overnight PSG remains the gold standard for evaluating sleep-disordered breathing in children
Abbreviations: OSA, obstructive sleep apnea; PSG, polysomnography; SDB, sleep disordered breathing.

Questions are often raised regarding the age in which to obtain a PSG. Data in neonates are still sparse; however, the use of PSG is gaining popularity in this age group in hopes of earlier diagnosis and intervention. The general consensus is that SDB should be documented objectively, but debate exists over the type of investigation needed, how to interpret the study, who should interpret the study, and what degree of abnormality constitutes a surgically treatable disease entity. Common measures include gas exchange, respiratory effort, airflow, snoring, sleep stage, body position, limb movement, and heart rhythm. Analysis of this data aids in differentiating diagnoses as listed in Table 3 , and indices include apnea/hypopnea index, oxygen saturation nadir, end tidal carbon dioxide, and arousals. With official recommendations and guidelines published by the American Thoracic Society and AAO-HNS, PSG is recommended in multiple clinical scenarios related to pediatric patients with craniofacial abnormalities.

Table 3
Clinical spectrum of sleep-disordered breathing (SDB)
Diagnosis AHI Oxygen Nadir End Tidal Carbon Dioxide Arousal Index Dispute Range Therapy
Primary snoring <1 >90 <53 <11 <1.5 Trial of nasal decongestant
UARS <1 >90 <53 RERA>1 Nasal decongestant
Mild OSA 1.5–5 86–90 >53 or 10% of night at 50 torr 7–11 AHI 1–5 for the lower limit of therapy No day symptoms: Nasal decongestant Day symptoms: may consider surgery, CPAP, Oxygen Therapy
Moderate OSA 5–10 75–85 >60 or 25% of night at 50 torr >11 Consider Surgery
Severe OSA >10 <75 >65 or 50% of night at 50 torr >11 Consider Surgery
Central apnea 2 1.5–5.5 Respiratory stimulant, oxygen therapy, neurologic workup
Abbreviations: AHI, apnea-hypopnea index; RERA, respiratory event–related arousals; UARS, upper airway resistance syndrome.

These recommendations include investigation of children with craniofacial abnormalities to differentiate benign/primary snoring from pathologic snoring and significant airway obstruction, to grade severity of OSA, and to plan medical or surgical intervention (see Table 3 ). In addition, follow-up PSG should generally be performed 12 to 18 months later in children previously diagnosed with OSA to evaluate the effectiveness of therapy, persistent symptoms after therapy, and worsening symptoms or to follow those children previously diagnosed with mild OSA. Routine clinical assessments should also be performed to ensure early detection of persistent, worsening, or recurrent OSAS. It is the practice of the authors to tailor follow-up studies to the individual. Follow-up PSGs are obtained every 12 months for children using CPAP and who use mechanical ventilation and 3 months after surgical intervention. For infants and those in rapidly evolving clinical situations (eg, PRS), PSGs may be obtained more frequently. Clinical indicators and common sense should be the ultimate guide to decision making.

Additional diagnostic tools include office-based nasopharyngolaryngoscopy (NPL) and operative laryngoscopy as well as bronchoscopy to evaluate synchronous lesions including pyriform aperture stenosis, nasolacrimal cysts, choanal atresia, laryngomalacia, vocal fold paralysis, laryngeal cysts or webs, subglottic stenosis, and pathologic conditions of the trachea ( Fig. 5 ). Awake examination of the upper airways in the clinic setting is focused on the identification of the pathologic conditions of the nasal and nasopharyngeal regions (septal deviation, inferior turbinate hypertrophy, nasal masses, and adenoid hypertrophy), pharyngeal region (tongue base obstruction and pharyngomalacia) and laryngeal region (vocal cord paresis and masses). Children may often tolerate awake NPL; however, the individual child's age and behavior dictate the likelihood of obtaining a meaningful examination. If the examination is limited because of cooperation, or lower airway evaluation is indicated, early operative airway evaluation with appropriate diagnostic tools is advocated by the authors.

Endoscopic view of ( A ) normal larynx, ( B ) grade III subglottic stenosis, and ( C ) vallecular cyst.
Fig. 5
Endoscopic view of (
A ) normal larynx, (
B ) grade III subglottic stenosis, and (
C ) vallecular cyst.

Risks of SDB secondary to corrective surgical procedures

Airway obstruction in individuals with CL/P has long been recognized as a complication of the primary and secondary reconstructive surgical procedures performed to improve speech and feeding. Primary cheilorhinoplasty is rarely associated with airway compromise with only case reports alluding to increased nasal obstruction resulting in exacerbation of the underlying OSA. Increased risk of OSA has been observed after palatoplasty. Differences in techniques, age at the time of surgery, and the inclusion of syndromic children contribute to the wide variation in the estimated 6% to 40% of increased risk after palatoplasty. Potential difficulties with intraoperative and postoperative airway management, particularly in an otherwise stable and thriving child, may warrant consideration for delay of palate repair in children with syndromes, particularly PRS. The availability of pediatric specialists and appropriate facilities (ie, pediatric anesthesia and pediatric intensive care unit) are strongly advised in these situations.

Pharyngeal flap procedures used for the correction of velopharyngeal insufficiency (VPI) are well known to be associated with SDB. Both retrospective and prospective studies have shown an increased risk of SDB in the order of 3% to 96%, with older studies reporting a risk of severe airway obstruction and death. A recent comparison of surgical procedures and the risk of SDB after surgical correction of CP or VPI revealed that surgical correction of VPI confers a higher risk for OSA than primary palatoplasty. Syndromes, PRS, and the presence of large tonsils put children at higher risk and must be considered when choosing surgical correction and therapy. The choice of technique does not seem to affect the incidence of OSA after surgical treatment of VPI because the use of either a pharyngeal flap or a sphincter pharyngoplasty produced relatively equivalent outcomes and complications. The utility in prophylactic removal of tonsils and adenoids in patients with VPI is not advocated by the authors unless OSA is clinically present. Even then, special consideration should be given to performing tonsillectomy alone compared with total or superior pole adenoidectomy secondary to concerns for causing worse VPI postoperatively.


Treatment of SDB

Treatment of SDB in children with craniofacial conditions depends on the severity of the disease, cause, age of the patient, and family/social circumstances influencing the ability to comply with treatment. Treatment with early airway intervention has been shown to improve feeding, growth, breathing, and sleep. MacLean and colleagues reviewed many treatment options considered for infants and children with isolated CL/P, including tonsillectomy with or without adenoidectomy, CPAP, or bilevel positive airway pressure, septoplasty, maxillary distraction, and reversal or modification of surgical procedures, which resulted in OSA.

Treatments reported in infants with PRS and micrognathia include prone sleep positioning, nasopharyngeal airways, nasal mask CPAP, tongue-lip adhesion, release of musculature of the floor of mouth, mandibular distraction, and tracheostomy. The authors advocate for early formal airway evaluation of all children with PRS and airway obstruction. The ideal paradigm for treatment does not exist, but the authors propose an algorithm in Fig. 6 .

Diagnosis and treatment algorithm in suspected airway abnormalities in Pierre Robin Sequence. ABN, abnormal; CT, computed tomography; NML, normal; PSG, polysomnography.
Fig. 6
Diagnosis and treatment algorithm in suspected airway abnormalities in Pierre Robin Sequence. ABN, abnormal; CT, computed tomography; NML, normal; PSG, polysomnography.

Nonsurgical Treatments

The use of prone positioning techniques is a noninvasive simplistic intervention, found to be valuable in infants with PRS with a 40% to 60% success rate in relieving obstruction. In those who have failed prone positioning, some consider the use of nasopharyngeal airways to be ideal. Meyer and colleagues were able to show 40% of infants who failed prone positioning were successfully managed by the use of nasopharyngeal airways in terms of relief of airway obstruction. The use of the nasopharyngeal airway allows for home care by parents, a reduction in hospital stay, increased weight gain, and no complications or readmissions. Reported complications associated with nasopharyngeal airways include nasal regurgitation, vomiting, and nasal excoriation, which were all shown to be mild.

An alternative effective method for the treatment of OSA is nasal CPAP, which can be used in both infants and children with CL/P. This requires regular reassessment of pressure requirements and settings in the sleep laboratory as the child grows. The risk for the development of maxillary hypoplasia from pressure of the nasal CPAP mask on the growing midface has been debated and shown to be reversible with mask modifications.


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