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90388Laser skin resurfacingNAVIN VIGINTRODUCTIONInterest in skin rejuvenation has seen a marked increase over the past few decades. Whereas ptotic facial tissue may demand a rhytidectomy or blepharoplasty, signs of sun damage (photodamage), scarring and hyperpigmentation can be treated relatively eectively with skin resurfacing. Treatments available include topical retinoids and chemi-cal peels, dermabrasion and laser resurfacing. Of these, laser skin resurfacing oers the patient the greatest, oen dramatic, clinical improvement and new technology has increased its availability and acceptability.GENERAL PRINCIPLESAgeing and photodamage change the skin in a number of ways. It becomes drier, thinner and less elastic. Rhytides (wrinkles), pigmentary dyschromias, lentigines and actinic keratoses are more visible. At the cellular level, atypical cells are seen in the epidermis, dermal collagen bres are thinner, less ordered and brotic and total col-lagen volume falls. Elastic bres fragment and degenerate and dermal vascularity diminishes.Changes due to photodamage are largely limited to the epidermis and upper dermis, rendering them ame-nable to laser skin resurfacing. is process uses laser light to remove, or modify, damaged outer layers of skin to stimulate epidermal re-epithelialization and dermal neocollagenosis. Following treatment, healthy epidermal cells migrate from nearby pilosebaceous units to replace atypical cells and new, compact dermal collagen replaces disordered elastotic material. e result is tighter, younger looking skin.Controlled thermal injury of the skin triggers this regeneration. In a process known as selective photother-molysis, lasers specically target intracellular water, one of four potential targets, or chromophores (others being collagen, melanin and haemoglobin). Each chro-mophore preferentially absorbs laser light of a certain wavelength allowing thermal injury to be restricted to a site where that chromophore is present. When applied, laser light is absorbed by water in supercial skin cells, causing vaporization, thermal damage and subsequent dermal remodelling.ere are two broad categories of laser used in resurfac-ing, the ablative and non-ablative, each of which can be traditional (non-fractional) or fractional. e traditional CONTENTSIntroduction 903General principles 903Choice of laser 904Pre-operative assessment 904Contraindications 904Pre-operative preparation 905Ablative laser resurfacing 905Clinical improvement 905Non-ablative laser resurfacing 906Fractional laser resurfacing 906Non-ablative fractional resurfacing 906Ablative fractional resurfacing 907Post-operative management 907Suggested readings 907 904 Laser skin resurfacingablative laser vaporizes away all tissue down to the papillary dermis. Although regarded as the gold standard, it is the most aggressive, and potentially complicated, resurfacing technique.Non-ablative laser resurfacing (NALR) sits at the other end of the spectrum. ese lasers selectively injure the dermis to stimulate dermal neocollagenosis but leave the epidermis intact. Recovery period is short but cosmetic improvements are more modest.Developed to overcome the risk prole of ablative lasers, fractional laser resurfacing combines elements of ablative and non-ablative resurfacing. It is based upon the concept of fractional photothermolysis (FP). Fractional lasers produce narrow beams of high-energy light to create evenly spaced columns of thermal injury to trigger regeneration sparing the majority of the skin. ey can be non-ablative (non-ablative fractional resurfacing, NAFR) or ablative (ablative fractional laser resurfacing, AFLR).CHOICE OF LASERis is guided by clinical indications, patient age and expectations and operator experience.In general, patients over the age of 50 with more advanced signs of photodamage will experience the greatest cosmetic improvement aer ALR. However, the post-operative course is long, demanding and poten-tially complicated. ey should understand the implica-tions of this before undertaking treatment. It is also less suitable for those with darker skin (Fitzpatrick IV–VI) and on non-facial such as the neck and chest skin. e lack of pilosebaceous units increases the risk of adverse events.If the patient is unwilling to tolerate the prolonged downtime and risks of ALR treatment, the best alterna-tive is fractional treatment. Outcomes are very good and patients prefer the shorter, less complicated recovery period. NALR is more appropriate for those under 50 with ne rhytides and early photodamage. Treatment can be readily repeated and the recovery period is negligible. NALR can also be used to treat pigmentary and vascular photoaging.Managing expectationsWhatever treatment is oered, it is critical that patients have realistic expectations of what it is likely to deliver, and understand the potential risks and side eects, at the outset. ose expecting dramatic improvements with non-ablative treatment will nd their outcomes unsatisfactory, as will patients expecting every wrinkle to disappear aer ALR. Patients deemed poorly prepared or unsuitable for a prolonged recovery period should be dissuaded from abla-tive treatment.PRE-OPERATIVE ASSESSMENTMedical historyA focused medical history is essential prior to any laser resurfacing procedure as certain aspects may render it inappropriate. In addition to a standard history, attention should be paid to the following aspects.Medical• History of delayed wound healing or immune de-ciency, or medications with this eect.• Herpes labialis. Previous history increases the risk of reactivation post-treatment.• Dermatological conditions such as scleroderma, lupus, vitiligo, psoriasis and verrucae. Can worsen aer abla-tive treatment.• Acne, active or previous, as this may are-up following treatment.• Oral retinoids, such as isotretinoin, increase the risk of hypertrophic scar formation post-operatively. Laser resurfacing should be delayed by at least 6–12 months following drug cessation.• Previous radiotherapy to head and neck increases the risk of scarring.Surgical• Previous mechanical or deep-chemical resurfacing. Ablative treatment may unmask hypopigmentation or brosis.• Existing skin brosis. Will limit laser ecacy.• Previous lower blepharoplasty procedures. Infra-orbital ablative resurfacing can increase risk of ectropion.• Previous face lis, or gras. e presence of non-facial skin requires a more conservative approach.• Tendency for keloid or hypertrophic scar formation. Some laser techniques can increase the risk of scar formation.CONTRAINDICATIONSese vary according to the type of treatment oered but include the following aspects.Absolute• Active infection: bacterial, viral and fungal• Active inammatory or autoimmune facial skin conditions• Oral retinoids (Roaccutane/isotretinoin) within past 12months Clinical improvement 905Relative• Unrealistic expectations of result• Inability to comply with post-operative management regime• Pregnancy or breastfeeding• History of therapeutic radiation exposure (ablative)Physical examinatione patient’s Fitzpatrick skin phototype should be recorded and high quality pre-operative photographs taken. Key fea-tures of photodamaged skin are documented; the presence of scars, keloid or skin lesions should be noted and further characterized if extensive. Suspicious skin lesions should be investigated and managed prior to resurfacing. Eyelid skin elasticity is assessed (scleral show, eyelid snap test and lid lag), particularly important if there is a high risk of ectro-pion (e.g. previous blepharoplasty, peri-orbital treatment).PRE-OPERATIVE PREPARATIONProphylaxis and skin careere are currently no established consensus-based pro-tocols, and practice varies according to practitioner. However, many advocate the following:• Oral antiviral prophylaxis, such as aciclovir or famci-clovir, is recommended prior to ablative or fractional resurfacing due to the risk of post-operative herpes simplex virus (HSV) infection. It is also recommended for those with a history of HSV infection. Prophylaxis begins 1 day prior to treatment and continues for 7–10 days post-operatively.• Evidence for the routine use of prophylactic antibiotics is limited. However, they are oen prescribed for abla-tive resurfacing or if there is an increased risk of post-operative infection.• Many practitioners commence patients on 4% hydro-quinone cream for 4 weeks prior to treatment, particu-larly for those with darker skin types, to limit risk of post-operative hyperpigmentation.AnaesthesiaLaser resurfacing can be uncomfortable. Topical anaes-thetic (e.g. eutectic mixture of local anaesthetics [EMLA]; 1:1 lidocaine 2.5% and prilocaine 2.5%) is applied to the face for 1 hour prior to treatment. Typically, 2 g is applied over 10 cm2. Local nerve blocks augment this and forced chilled-air devices further minimize discomfort. Some patients may benet from anxiolytics, or require intrave-nous sedation or a general anaesthetic.ABLATIVE LASER RESURFACINGe two main lasers commonly used for ablative resur-facing are the carbon dioxide (CO2; 10,600 nm) and the erbium:yttrium-aluminium-garnet (Er:YAG; 2,940 nm). Usage of a third, the erbium:yttrium-scandium-gallium-garnet (Er:YSGG; 2,790 nm), is currently limited. ALR is commonly used to treat facial rhytides but can treat coarse skin, minor dyspigmentation and dermatopathologic enti-ties (actinic keratosis, xanthelasma).CO2 lasersAblative CO2 lasers can deliver energy in pulses or con-tinuous waves (CW). ese are high-energy, short-pulsed (<1 ms) devices or lower energy, scanned-CW devices. e latter use rapid scanning to limit a focused beam to <1 ms skin contact time. is is important in reducing unwanted thermal damage.Each pulse or scan of the laser delivers uences (J/cm2) of 4–5 J/cm2, sucient energy for total epidermal and partial dermal vaporization. Each laser pass vaporizes to the depth of 20–50 μm with an underlying area of resid-ual thermal damage (RTD) of 100–200 μm, enough to strongly stimulate dermal collage production. To reduce the risk of inadvertent deeper thermal injury, and sub-sequent scarring, it is important that numbers of short-pulsed passes over a particular area are limited, or a low overlap setting is used on the scanned-CW device. Energy should be reduced around the eyes, but may be increased around the mouth.Er:YAG laserse Er:YAG laser emits wavelengths at 2,940 nm, and water-containing tissues absorb Er:YAG light 16 times more eciently than CO2 lasers. Consequently, much of the energy escapes as steam reducing thermal injury to surrounding tissue. Although this reduces the risk of unwanted eects, it also limits the shrinkage of dermal collagen bres and haemostasis. Only 1–2 μm of tissue ablation occurs per J/cm2, so uences delivering between 5 and 15 J/cm2 are used according to the area treated. Many more passes may be required to achieve the same degree of ablation as a single pass of the CO2 laser making this technique more operator sensitive.CLINICAL IMPROVEMENTA single treatment session with CO2 laser is sucient to deliver signicant reduction in rhytides, particularly in the peri-orbital and peri-oral areas, and outcomes are unmatched by other laser technology. However, downtime is long and many patients are oen unwilling to undergo 906 Laser skin resurfacingsuch a demanding and potentially risky procedure. e less signicant thermal injury of the Er:YAG laser means a more modest rhytid reduction and skin tighten-ing eect than seen with the CO2 laser. is makes it more suitable for patients with mild to moderate rhytides.Side eﬀects and complications• Erythema usually settles within 1–2 months but may persist for up to 12 months aer CO2 ALR. Flushing may also occur.• Post-inammatory hyperpigmentation: occurs in 36% of patients, but up to 80% in those with darker skin.• Delayed hypopigmentation: unexpected delayed loss of pigment 6–12 months aer treatment in 8%–16% of patients.• Infection: bacterial and fungal infections are uncom-mon but HSV reactivation in almost 10% of patients.• Acneiform eruptions: up to 10% of patients.• Hypertrophic scar: uncommon (<2%) and minimized by sound patient selection and appropriate intra- operative laser technique.In general, the Er:YAG laser is less uncomfortable and asso-ciated with more rapid recovery and fewer adverse events.NON-ABLATIVE LASER RESURFACINGNALR was developed primarily to overcome the complica-tions of ALR, achieved partially by stimulating the dermis whilst sparing the epidermis. NALR systems allow resur-facing of non-facial skin such as the neck, chest or back, unlike ablative resurfacing, and are also suitable for darker-skinned patients. NALR is suitable for the treatment of mild photodamage, acne scars and dyspigmentation.ree main groups of non-ablative systems exist, infrared (IR) lasers, visible lasers (pulsed-dye lasers, PDLs) and intense pulsed light (IPL) sources. IR lasers in use are the Nd:YAG (1,320 nm), diode (1,440 nm) and Er:glass (1,540nm). ese systems can deliver between 5 and 40 J/cm2 to the skin and target the dermis. Epidermal sparing is achieved by concomitant cooling with cryogen spray. PDL (585–595 nm) and IPL (550–1200 nm) both target haemoglobin and are useful in the treatment of telangiectasia and diuse erythema. e IPL also tar-gets melanin and can be used to treat pigmented lesions and melasma. Approximately 4–6 treatment sessions are required, each given every 2–4 weeks.Clinical outcomeIR lasers deliver satisfactory outcomes when used to treat ne rhytides and scars. PDL and IPL successfully treat vascularity and pigmentary changes. IPL is oen the pre-ferred treatment for rosacea and telangiectasia.Side eﬀects and complicationse main advantage of NALR is the low risk of com-plications. Patients usually return to normal activities immediately.• Post-operative erythema and oedema: usually settles within 24 hours.• Blistering: uncommon aer treatment and associated with inadequate cooling at time of procedure.FRACTIONAL LASER RESURFACINGe concept behind this approach is to thermally injure a fraction of the skin surface whilst leaving interven-ing areas of untouched tissue to speed healing and allow deeper laser penetration to stimulate collagen production further. It can be either non-ablative or ablative and is suit-able for use on non-facial skin.NON-ABLATIVE FRACTIONAL RESURFACINGNAFR is suitable for ner rhytides, most scars, textural imperfections, dyspigmentation and melasma.A number of devices have been approved for NAFR. ese are mid-IR lasers (1,440, 1,535, 1,540 and 1,550 nm) and the 1,927-nm thulium laser. NAFR lasers pro-duce 125–250 equally spaced ablated columns, known as microthermal zones (MTZs), per cm2. Each MTZ is 70–150 μm in diameter and 200–1,000 μm deep. e sub-sequent dermal injury stimulates neocollagenosis and dermal remodelling. Beyond the MTZs, little thermal damage occurs. e intact stratum corneum acts a biolog-ical dressing and thermally injured tissue heals rapidly, supported by spared skin. Eight to twelve passes are usu-ally performed; four to six sessions are normally required at 2–4 week intervals.OutcomesNAFR satisfactorily improves the appearance of milder signs of photodamage, melasma and scarring. Only ne rhytides disappear and some argue that this highlights the importance of treating the epidermis more fully to achieve better rhytid reduction.Side eﬀects and complications• Erythema and oedema: resolve within 3–4 days.• Healing is usually complete within 7 days.• Prolonged hyperpigmentation has been reported in darker skinned patients. Suggested readings 907ABLATIVE FRACTIONAL RESURFACINGAFR was developed in an attempt to improve the ecacy of NAFR, combining the concept of FP with tissue abla-tion. ese lasers are oen used against rhytides and laxity but perform well against photodamage, most scars, dys-pigmentation and melasma.A variety of devices exist with parameters that can be adjusted according to clinical requirements. AFR lasers vary according to wavelength used (CO2, Er:YAGG, Er:YSGG), power, microspot size (i.e. laser beam diameter), density and pulse duration. Many of these can be adjusted to alter the eects of treatment. A short, high-energy pulse combined with a small microspot size can penetrate up to 2 mm into tissue, useful for deep rhytides. Conversely, a large microspot size ablates supercial tissue and is useful for treating ne rhytides. Parameters can also be adjusted to minimize recovery times.Each device interacts with the skin in a slightly dier-ent manner but creates well-spaced microscopic columns of ablated tissue, including all epidermal layers, deep into the dermis. ermal injury stimulates collagen contrac-tion, neocollagenosis and remodelling and molecular alterations similar to those seen in CO2 ALR are observed. Re-epithelialization is complete within 7 days, facilitated by areas of spared skin.e number of treatment sessions required depends upon the clinical indication and parameter settings. Normally, one to two sessions are required at 6–12 week intervals.OutcomesAFR can signicantly improve both ne and deep rhyt-ides, skin texture, lentigines, scars and areas of dyspig-mentation. On-going collagen remodelling aer treatment mean improvements may take 3–6 months to be fully real-ized. Overall, AFR outcomes fall just short of those seen aer traditional ablative resurfacing.Side eects and complicationsis technique oers a relatively short recovery period (1 week) and a lower risk of developing adverse events compared to ALR, but it is far from complication-free.• Erythema and oedema: normally settle within 3–6 days• HSV infection (1%–2%)• Acneiform eruptions (2%–5%)• Erythema >1 month (1%)• Transient hyperpigmentation (<1% Fitzpatrick I and II, 12% Fitzpatrick III and VI)• Scarring: only reported aer neck treatmentPOSTOPERATIVE MANAGEMENTNon-ablative resurfacingWound care is minimal. Patients are advised to use a fragrance-free cleanser and moisturizer for 1–2 weeks aer treatment, should avoid exfoliating and practice sun avoidance. Patients can return to their regular skin care regime aer this period.Ablative resurfacingMeticulous wound care is essential to minimize the risk of complications. Aer traditional ablation, the skin pro-duces large amounts of exudate that must be wiped away regularly as crusting will increase the risk of infection. e face is soaked continuously with wet sponges dipped with very dilute acetic acid solution. A very ne layer of healing ointment or petroleum jelly is applied 3–4 times daily and continues until re-epithelialization is com-plete (up to 2weeks). Concomitant use of ice gauze or ice packs and anti-inammatories can help reduce oedema. Aer fractional ablation, regular cleaning is also advised but as the majority of the epidermis is intact, there is l ittle exudate. Healing ointment is applied in the same manner for 4–6days.Aer this period, both groups are advised to use fragrance-free cleansers, moisturizers and sunscreen regularly.SUGGESTED READINGSAlexiades-Armenakas MR, Dover JS and Arndt KA. Fractional laser skin resurfacing. J Drugs Dermatol. 2012 Nov; 11(11): 1274–1287.Aslam A and Alster TS. Evolution of laser skin resurfacing: From scanning to fractional technology. Dermatol Surg. 2014 Nov; 40(11): 1163–1172.Carniol PJ, Hamilton MM and Carniol ET. Current status of fractional laser resurfacing. JAMA Facial Plast Surg. 2015; 17(5): 360–366.Kohl E, Meierhöfer J, Koller M, Zeman F, Groesser L, Karrer S et al. Fractional carbon dioxide laser resur-facing of rhytides and photoaged skin—Prospective clinical study onpatient expectation and satisfaction. Lasers Surg Med. 2015 Feb; 47(2): 111–119.Lipozenčić J and Mokos ZB. Will nonablative rejuvenation replace ablative lasers? Facts and controversies. Clin Dermatol. 2013 Nov–Dec; 31(6): 718–724.Preissig J, Hamilton K and Markus R. Current laser resurfacing technologies: A review that delves beneath the surface. Sem Plast Surg. 2012; 26(3): 109–116.Shah S and Alam M. Laser resurfacing pearls. Sem Plast Surg. 2012; 26(3): 131–136.