Complications in Laser and Light Surgery
Tina S. Alster, Ehzabeth L. Tanzi
INTRODUCTION
Complications of cutaneous laser surgery can be under- stood by reviewing the evolution of laser technology over the past four decades. Lasers initially were designed to operate in a continuous-wav" (C\M) mode, which produced a continuous beam of radiation that subsequentiy was absorbed by a tissue chromophore. Although particular skin structures could be destroyed using these early lasers, their use was limited because the energy emitted not only altered the target, but also conducted heat into adjacent nonirradi- ated tissue. The nonselective thermal injury produced in adjacent tissue resulted in significant side effects and com- plications, namely, hypopigmentation and scarring
The safety and efficacy expected from modern laser systems can be attributed to the ground-breaking work of Anderson and Parrish in the 1980s Their theory of selec- tive photothermolysis outlined the mechanism for specific tissue destruction through manipulation of the type of laser energy produced and the manner in which it was delivered Thus, a specific chromophore or target can be selectively destroyed with minimal thermal tissue damage when the laser wavelength matches that absorbed by the chromophore and when the target is exposed to the laser energy for an interval shorter than its thermal reiaxation time (the time required for the target to cool to half its peak temperature after laser irradiation)
Lasers designed based on the theory of selective photothermolysis are more specific and have a lower risk profile in terms of scarring; however, they have their own unique side effect profiles. Depending upon the wave- length and puise durations delivered, dyspigmentation, epidermal cell injury, textural changes, as well as crustrng and tissue splatter potentially can occur. It is important to remember that even the safest of lasers can cause injury if used inappropriately Application of stacked pulses, use of excessive energy or power settings, and improper patient selection potentially can result in a high rate of morbidity with any laser system.
PATIENT SELECTION
Because of the varied side effects and complications pos- sible after cutaneous laser surgery, it is essential that each
patient receive consultation and counseling before treat- ment to assess his or her specific risk of adverse sequelae.
Laser surgeons must spend time educating patients on the realities of laser treatment and the potential side effects that may occur. During the consultation, clinical photographs and written material can enhance the patient's understanding of the procedure, expected clinical outcome, and potentiai complications. It is also important that patients understand the importance of good wound care after a laser procedure Preoperative laser evalua- tion should include a basic medical history, including documentation of medications and allergies. A history of smoking, abnormal scarring, excessive sun exposure, allergic or inflammatory conditions, herpes simplex virus (HSV] outbreaks, immune disorders, or previous cosmetic procedures within the involved area should also be ascer- tained Proper pretreatment education and close physician follow-up helps to reduce morbidity and al1ows fbr early recognltion and management of potential problems.
L a s e r s a n d L i g h t s V o l u m e l l
unacceptably high rates of scarring and permanent pig- mentary alterations due to prolonged tissue exposure to laser energy. The newer COz and Er:YAG systems were developed taking into account the principles of selective photothermolysis, so that high laser energies and short pulse durations best effected tissue ablation with minimal thermal injury of residual skin.
Other factors affecting the risk of adverse reactions with laser resurfacing include the number of laser passes performed, the energy densities used, the degree of pulse or scan overlap, the skin type and pretreatment condition of the individual patient, the anatomic location to be resurfaced, and the individual expertise of the iaser surgeon. True adverse reactions, however, are rare and must be differentiated from the normal Dost-trearmenr morbidity that all patients experience after ablative laser skin resurfacing, including erythema, edema, crusting, and serous discharge
o Normal healing process
After cutaneous laser resurfacing, all patients experience some degree of immediate post-treatment morbidity Because laser ablation involves complete epidermal vapor- ization and upper papillary dermal destruction and re- modeling, the most common immediate post-treatment reactions include intense erythema, edema, and copious serous discharge that persist until re-epithelialization is complete If a pulsed CO2 laser is used to deliver multiple passes to the skin, re-epithelialization is complete in an average of 7-9 days, compared with 4-5 days after short- pulsed Er:YAG laser treatment The degree of erythema correlates directly with the number of laser passes deliv- ered due to the increasing depth of penetration and degree of residual thermal injury The pulsed CO2 laser ablates tissue to a depth of 20-60 pm with each consecutive pass and produces zones of thermal damage ranging from 20 to I 50 pm after a typical skin resurfacing procedure, com- pared with 20-50 pm of residual thermal damage with the short-pulsed Er:YAG laser Therefore, patients treated with a traditional multiple-pass CO2 laser technique expe- rience more persistent and intense erythema, especially in the immediate postoperative period Maximum intensity erythema after CO2 laser resurfacing occurs 8-0 days postoperatively and lasts an average of 3-6 months/ com- pared with 2-4 weeks for short-pulsed Er:YAG laser treated patients. Edema is another normal consequence of cutaneous laser treatment and is most Dronounced on the second and third postoperative days with either laser.
Application of cool compresses and ice alleviates the edema, which resolves after several days.
Newer trends in ablative facial resurfacing have emerged that offer modest clinical improvement in rhvtides and atrophic facial scars with reduied postoperative morbidity and shorter recovery times than traditional, multi-pass CO2 laser skin resurfacing. Less aggressive technrques include single-pass CO2 laser ablation and use of modu- lated fvariable-pulsed Er:YAG or combined Er:YAG/
CO2) laser systems. The single-pass CO2 laser technique involves application of a single set of non-overlapping scans to the skin The partially desiccated tissue is left intact to serve as a biologic wound dressing. At standard treatment parameters, this method ablates the entire epi- dermis The modulated Er:YAG laser systems emit light with extended pulse durations [up to 500 ps) producing larger zones of thermal damage compared with traditional short-pulsed Er:YAG laser systems. In addition, increased thermal coagulation of dermal vessels is effected, permit- ting deeper tissue penetration and improved intraopera- tive field vrsualization. These larger zones of collateral tissue damage resuit in beneficial tissue effects that approximate those of the CO2 laser The use of these newer methods are associated with shorter and less severe erythema, edema, and postinflammatory hyperpigmenta- tion compared with traditional, multiple-pass CO2 laser skin resurfacing.
A meticulous postoperative wound care regimen is the best measure to ensure proper healing and rapid resolution of symptoms during the recovery process. Two different recovery regimens are available to patients after resurfac- ing: the open and closed wound dressing techniques. The open technique involves the liberal application of a healing ointment or plain petrolatum with cool wet compresses every 2-3 hours for the first several days after the proce- dure. The open technique is labor intensive and may be associated with increased patient discomfort but allows excellent visibility of the resurfaced skin and permits early detection of untoward side effects. The closed technioue involves the placement of a semiocclusive biosynthetic dressing over the irradiated skin in an attempt to decrease patient discomfort and speed re-epithelialization by limiting crusting The closed system is relatively easy for patients to use and so has greater compliance. However, if wound dressings are left in place for extended periods of time, potentially higher rates of infection may occur.
In addition, the use of semiocclusive dressings may con- tribute to wound maceration and, if opaque, render direct visualization of the resurfaced skin difficult. Some laser surgeons are now using a combined open and closed wound care approach to maximize postoperative healing.
The closed technique is used for the first 2 days post procedure when the edema, serous drainage, and discom- fort are greatest, followed by an open technique for the remainder of the recovery period until re-epithelialization is completed. Proper pretreatment education and close physician follow-up, in addition to a carefully executed home recovery regimen, ensures minimal post-treatment morbidity and allows for complications to be detected and addressed expeditiously.
. Complications of cutaneous laser resurfacing
Complications of cutaneous laser resurfacing can be cat- egorized according to severity (Tabte Z.r) Mild side effects or complications include prolonged erythema and edema,
MiId
Prolonged erythema Acne and milia {ormation Allergic/irritant contact dermatitis Petechiae
Prurilus Moderate HSV reactivation
Superf icial cutaneous infection Post-inf lammatory hyperpigmentation Delayed-onset hypopigmentation Severe
Hypertrophic scarring Ectropion formation Disseminated infection
acne or milia formation, irritant or allergic contact derma- titis, and persistent pruritus. Moderate complications include reactivation of HSV, superficial bacterial or fungal infection, transient post-inflammatory hyperpigmenta- tion, and permanent, delayed-onset hypopigmentation.
The most serious complications of laser skin resurfacing are rare and include hypertrophic scarring, ectropion formation, and disseminated infections. The risk of these untoward side effects are significantly reduced when appropriate pretreatment patient selection is made, proper surgical technique is used, and when the post-treatment recovery period occurs under optimal healing conditions.
P R O L O N G E D E R Y T H E M A
Post-treatment erythema is an expected consequence of laser skin resurfacing and occurs in every patient after treatment (Fig. Z.t). Erythema is most intense after CO2 laser resurfacing and may persist for 6 months or longer.
Short-pulsed, Er:YAG laser-induced erythema is usually less severe and of shorter duration, lasting several weeks on average. The risk of prolonged erythema is increased when multiple laser passes or inadvertent stacking or over- lapping of laser pulses are performed, producing greater depths of tissue injury. It has also been proposed that aggressive debridement of the skin to remove partially desiccated tissue during surgery may also contribute to excessive erythema Postoperative wound infection and dermatitis irritate the skin and may also result in persis- tent erythema. Patients who have acne rosacea or who regularly use topical tretinoin prior to resurfacing may be predisposed to intensified erythema.
Topical ascorbic acid has been shown to decrease the severity and duration of postoperative erythema. It is best applied when re-epithelialization has been completed in order to avoid irritation of the denuded skin surface, which could further aggravate the erythema. Application of topical corticosteroids will not reduce normal post- operative erythema and could potentially retard wound
Complications in Laser and Light Surgery
Fig.7.1 Erythema is an expected consequence of ablative CO, or Er: YAG laser skin resurfacing, but has a tendency lo be more prolonged in patients after multiple-pass CO, laser procedures. No specific treatment is generally indicated
healing and therefore should not be prescribed with the intention of speeding resolution of erythema. However, focal areas of erythema with induration and tenderness may herald incipient scar formation and should be promptly and aggressively treated with potent [class I) topical corticosteroid preparations or pulsed dye laser irradiation
A C N E A N D M I L I A
Acne flares and milia formation are relatively common side effects of cutaneous laser resurfacing due to the use of occlusive healing ointments and biosynthetic dressings during the acute recovery process. Aberrant follicular epithelialization during healing may also contribute to acne exacerbation within I to 2 weeks postoperatively.
Patients with a prior history of acne are at particular risk of its development after resurfacing.
Acne has been reported to occur in as many as 800/o of patients and milia in upwards of 140/o who undergo laser skin resurfacing. Treatment is usually not necessary for mild flares since spontaneous resolution is commonly observed once use of the occlusive ointments and dress- inss are discontinued Short courses of oral antibiotics ,rrih
"r tetracycline or minocycline may be necessary for moderate-to-severe acne flares especially in patients with a strong acne predisposition. Once the skin has re-epithe- lialized, topical antibiotics (e.g., erythromycin, clindamy- cin) can be used without fear of allergic or irritant contact dermatitis Milia typically resolve spontaneously during continuation of the re-epithelialization process, but can also be remedied with topical application of retinoic acid or manual extraction. Intralesional corticosteroids may be necessary for the rare inflamed cyst
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C O N T A C T D E R M A T I T I S
Contact dermatitis after cutaneous laser resurfacing can occur in over 50(/o of patients and is usually irritant in nature (Fig. 7.2) Because of the de-epithelialized state of newiy resurfaced skin, the normal protective epidermal barrier is impaired, rendering the skin more susceptible to irritation. An allergic or irritant reaction to fragrances or allergens contained within a wide variety of topical ointments, soaps, moisturizers, or cosmetics may develop Topical antibiotics (e g., Neosporin, Polysporin, or baci- tracin) are the most common offending agents so their use should be avoided during the re-epithelialization process.
It is also imperative that patients refrain from application of self-prescribed remedies during recovery since many herbal or other 'natural'
compounds may exacerbate irrita- tion and contribute to postoperative morbidity.
Signs and symptoms suggestive of an irritant or allergic contact dermatitis include diffuse and intense facial ery- thema and/or pruritus. The eczematous eruptions observed are not usually the result of a true type IV allergic reac- tion, as patch tests fail to reveal allergy in the majority of cases. Since most reactions are ofthe irritant variety, only the sole use of bland, non-fragrance-containing emollients is necessary during recovery. \44ien an allergic or irritant contact dermatitis is suspected, all potential inciting agents must be immediately discontinued Although most reactions will clear once the offending agents are removed, the use of strong corticosteroids and oral antihistamines may speed the resolution of the dermatitis and reduce the risk of scarring. In severe cases, oral corticosteroids can be prescribed to decrease the inflammatory response Frequent application of cool compresses can also alleviate prurltus
I N F E C T I O N
Viral, bacterial, and fungal infections may complicate any ablative laser resurfacing procedure with development of signs and symptoms during the first postoperative week before re-epithelialization is complete (Fig. 7.3). These infections must be promptly identified and treated so as to avoid scarring, delayed wound healing, infection with other opportunistic pathogens, or dissemination Reactiva- tion of HSV is the most frequently occurring infectious sequela of cutaneous laser resurfacing. Because of the high rate of asymptomatic carriers of HSV infection, al1 patients must be assumed to be carriers of the virus. Therefore, any patient, regardless of prior HSV history, planning to undergo fu1l-face or perioral resurfacing should receive prophylactic oral antiviral therapy. Despite adequate anti- viral prophylaxis, 2-70/o of laser-treated patients experi- ence HSV reactivation.
Detection of a postoperative herpetic infection may be difficult because of the lack of intact eoithelium \\4rereas a herpetic infection on normal skin typically presents as intact vesicopustules on an erythematous base, an out- break on laser-treated skin may only appear as superficial erosions (FiS.l.d There may also be associated symptoms of pruritus or dysesthesia with delayed re-epithelializa- tion. Since dissemination of the herpes virus may result in atrophic scarring, suspected HSV infection shouid be treated aggressively with an appropriate antiviral agent.
Oral antiviral agents (e.g , acyclovir, famciclovir, vala- cyclovir) should be initiated l-2 days prior to the resur- facing procedure and continued for another 7-10 days until re-epithelialization is complete If a herpetic out- break occurs despite adequate prophylaxis, drug dosages should be increased to maximum zoster levels or a chanse
Fig. 7.2 Contact dermatitis is a relatively common side effect of laser skin resurfacing because of the impairment of the protective epidermal barrier that occurs with skin ablation Topical antibiotics and other irritants should be avoided in the immediate postoperative period until re-epithelialization is completed Oral antihistamines and application of cool compresses and topical corticosteroids speed its resolution and reduce the risk of scarrino in severe cases
Fig. 7.3 Excessive crusting, discharge, and slow wound healing are signs of infection Appropriate bacterial, viral, and fungal cultures should be obtained prior to olacement on oral antibiotics
1 0 3
to a different antiviral should be made, as viral resistance to the initially prescribed drug may have occurred. For the rare case of herpetic dissemination, intravenous ad- ministration of acyclovir with hospitalization becomes necessary
Superficial cutaneous bacterial and fungal infections may also complicate recovery from cutaneous laser resur- facing Bacterial infections are often due to excessive wound occlusion during the initial postoperative recovery period and therefore are more commonly seen when a closed wound technique is used. The moist environment of newly resurfaced skin provides an ideal medium for overgrowth of opportunistic pathogens Staphylococcus aureus and Pseudomonas aeruginosa are the most com- monly isolated bacteria whereas Candida albicans is the most commonly isolated fungus, although many wounds have multiple contaminating organisms on culture. Patients with nasal colonization of staphylococci may be more sus- ceptible to infection; however, it has not been proven that prophylactic topical antibiotic ointment decreases this risk.
Signs and symptoms of an acute bacterial process include focal areas of increased erythema, purulent dis- charge, pain, delayed healing, and erosions with crusting.
A meticulous postoperative wound care regimen is essen- tial to decrease the risk of bacterial infection. Patients should be advised to wash their hands with antibacterial soap before dressing or ointment application. Washcloths and other linens should not be reused during the recovery process Frequent dressing changes and dilute acetic acid compresses are additional measures that keep the wound clean and free of infection If an infection is suspected, patients should be given broad-spectrum antibiotics [e g., semisynthetic penicillins or first generation cephalospo- rins) until results of bacterial cultures with antibiotic
Complications in Laser and Light Surgery
sensitivities are obtained. Although antibiotic prophyiaxis remains standard practice for those patients at increased risk of infection [e.g., immunosuppression, mitral va]ve prolapse with regurgitation, valvular heart disease), its routine use is controversial, with large scale prospective and controlled studies indicated to determine if anti- microbial coverage is warranted in all patients.
P I G M E N T A R Y A L T E R A T I O N
Transient postinflammatory hyperpigmentation is one of the most common complications of cutaneous laser resur- facing occurring in one third of all treated patients regard- less of skin tone (Fig. Z.S). Individuals with darker skin phototypes fFitzpatrick IV-VI) almost universally hyper- pigment after cutaneous ablative resurfacing and must be warned of this reaction prior to the procedure Hyper- pigmentation usually develops 3-4 weeks postoperatively and can persist for several months without intervention.
Nthough postinflammatory hyperpigmentation following variable-pulsed Er: YAG laser skin resurfacing can last longer than that seen after treatment with a short-pulsed Er: YAG laser, it is not as persistent as that observed after multiple-pass CO2 laser skin resurfacing (average: variable- pulsed Er:YAG laser, 10.4 weeks; CO2 laser, l6 weeks).
Because the cutaneous dyspigmentation is so conspicuous, most patients seek treatment to hasten its resolution.
Treatment options for hyperpigmentation include topical bleaching agents [hydroquinone, kojic acid), retinoic, azelaic, ascorbic, and glycolic acid compounds, as well as broad-spectrum sunscreens to prevent further ultraviolet light-induced melanin synthesis. Mild glycolic acid peels (30-40%J may also hasten pigment resolution and can be reoeated at 2-4 week intervals for more efficient results (FiS 2.6). Since any of these topical remedies has the
Fig. 7.4 Erosions, ralher than vesicopustules, indicate HSV infection in laser-treated (de-epithelialized) skin Aggressive treatment with high-dose oral antiviral agents should be initiated and continued for 7-'10 days (until re-epithelialization has been achieved)
Fig. 7.5 Postinflammatory hypopigmentation is most common in patients with darker skin tones and is initially observed 3-4 weeks after laser skin resudacing lt occurs with equal frequency in patients treated with COz or Er:YAG lasers, bul tends to persist longer after CO, laser and/or multiple-pass procedures