Lasers in Surgery and Medicine 41:185���188 (2009) Hypertrophic Scarring of the Neck Following Ablative Fractional Carbon Dioxide Laser Resurfacing Mathew M. Avram, MD, JD,1* Whitney D. Tope, MPhil, MD,2 Thomas Yu, MD,3 Edward Szachowicz, MD, PhD,4 and J. Stuart Nelson, MD, PhD 5 1Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 2Advancements in Dermatology, Edina, Minnesota 3Dermatology and Clinical Skin Care Center, Bethesda, Maryland 4Facial Plastic Surgery, Edina, Minnesota 5Beckman Laser Institute, University of California, Irvine, California Background: Ablative fractional carbon dioxide (CO2) laser treatments have gained popularity due to their efficacy, shortened downtime, and decreased potential for scarring in comparison to traditional ablative CO2 resur- facing. To date, scarring with fractional CO2 lasers has not been reported. Objective: Five patients treated with the same fractional CO2 laser technology for photodamage of the neck were referred to our practices 1���3 months after treatment. Each patient developed scarring. Of the five cases, two are discussed in detail. The first was treated under general anesthesiaonthefaceandanteriorneckatapulseenergyof 30 mJ (859 mm depth) with 25% coverage. Eleven days after treatment, three non-healing areas along the horizontal skin folds of the anterior neck were noted. At 2 weeks after CO2 ablative fractional resurfacing, these areas had become thickened. These raised areas were treated with a non-ablative fractionated 1,550 nm laser to modify the wound healing milieu. One week later, distinct firm pale papules in linear arrays with mild hypopigmentation had developed along involved neck skin folds. Skin biopsy was performed.Forthesecondpatient,theneckwastreatedata pulse energy of 20 mJ (630 mm depth) with 30% coverage of the exposed skin, with a total treatment energy of 5.0 kJ. Minimal crusting was noted on the neck throughout the initial healing phase of 2 weeks. She then experienced tightness on her neck. Approximately 3 weeks after treat- ment, she developed multiple vertical and horizontal hypertrophic scars (HS). Results: Histopathology for the first case confirmed the presence of a hypertrophic scar. The papules in this case completely resolved with mild residual hypo- pigmentation after treatment with topical corticosteroids. HS failed to resolve in the second case to date after 1 month. Conclusion: As with traditional ablative CO2 laser resurfacing, HS is a potential complication of ablative fractional CO2 laser resurfacing, particularly on the neck. With early diagnosis and appropriate treatment HS of neck skin may be reversible. We urge caution when treating the neck with this device and close attention to wound care in the post-operative period. Lasers Surg. Med. 41:185���188, 2009. �� 2009 Wiley-Liss, Inc. Key words: fractional resurfacing fractional photother- molysis ablative fractional resurfacing CO2 laser resur- facing fractional CO2 resurfacing laser complications hypertrophic scar Fraxel neck rejuvenation INTRODUCTION Fractional photothermolysis is a method of skin rejuve- nation that produces a unique thermal damage pattern characterized by multiple columns of thermal damage, known as microthermal treatment zones (MTZs) sur- rounded by untreated tissue [1]. The untreated tissue serves a reservoir for rapid healing after treatment. Originally,fractionalphotothermolysisusingnear-infra- red light, which left the stratum corneum intact, was confined to non-ablative procedures. Recently, the concept of fractional photothermolysis has been extended to ablative laser wavelengths produced by erbium:YAG (2,940 nm) and carbon dioxide (10,600 nm) lasers [2,3]. Ablative fractional resurfacing (AFR) has been shown to provide safe and effective improvement of facial rhytides, photodamaged skin, and acne scars [4,5]. AFR Er:YAG and CO2 lasers are the first devices which safely and effectively ablate reticular dermal tissue in resurfacing photodam- aged skin [6]. While not as effective as traditional ablative resurfacing, AFR is thought to be a safer procedure due to its unique thermal damage pattern, which spares most of the treated area. In comparison, AFR appears to signifi- cantly diminish post-procedure erythema, edema, wound care,downtime,hyper-orhypopigmentation,infection,and scarring. To date, scar formation after treatment by ablative fractional lasers has not been reported. Er:YAG and CO2 laser AFR are perceived by some as being so safe that their use has been delegated to non-physicians. *Correspondence to: Mathew M. Avram, MD, JD, 50 Staniford Street, Suite 250, Boston MA 02114. E-mail: mavram@partners.org Accepted 21 January 2009 Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/lsm.20755 �� 2009 Wiley-Liss, Inc.

In the past few months, several patients have presented to our offices with hypertrophic scars (HS) on the neck after treatment with the same type of ablative fractional CO2 laser.Duetorestrictionsimposedbypotentiallitigation,we discuss in detail only two of these five patients. We present photographic images of all five patients. With these case data, we aim to educate and alert our colleagues as to the potential for scarring of the neck with this new approach to skin photorejuvenation. CASE PRESENTATIONS Patient #1 A 57-year-old Caucasian woman with Fitzpatrick photo- type II skin underwent CO2 laser AFR (Fraxel re:pair1, Reliant Technologies, Inc., Mountain View, CA) under general anesthesia for treatment of facial acne scars and neckphotodamage(rhytidesandlaxity).Thepatienthadno history of isotretinoin use within 1 year of the procedure. Her anterior neck and chest were treated using a pulse energy of 30 mJ (859 micrometer depth) with treatment coverage of 25% of the exposed skin. Post-operative care consisted of wet gauze soaks and bland emollients. The post-operative course was unre- markable until day 7 when three horizontal ������necklace-like������ lines of delayed wound healing were noted on the anterior neck. Wound care then included cleansing and application of bacitracin zinc ointment every 2 hours. On post- operative day 11, the non-healing areas became tender and the patient discontinued the cleansing due to pain. The affected areas now featured small papules and diffuse erythema. Bacitracin application continued. No pustules or vesicles were present at anytime in the post- operative period. No bacterial, fungal or viral cultures were performed. On post-operative day 15, the area was treated with a non-ablative fractional Er:glass (1,550 nm) resurfacing laser (Fraxel re:store1, Reliant Technologies, Inc., Moun- tain View, CA) in order to ������modify healing������ and ������flatten thickenedareas.������ A10mJ(555 mmdepth),pulseenergywas applied for 14% skin coverage. On post-operative day 20, the patient developed a pruritic eruption on the anterior neck consisting of macular erythema, desquamating scale, and mild induration in horizontal arrays. The rash was also notable for patchy incomplete hypopigmentation. Oral benadryl did not ameliorate the rash or pruritus. At that time, a diagnosis of a resolved cutaneous candidiasis infection with residual inflammation was considered and treated with 0.1% triamcinolone ointment twice daily for 1 week. Six days later, the eruption had completely resolved. Physical examination was notable for multiple well- defined, firm pale papules in linear arrays along skin folds of the anterior neck (Fig. 1). A clinical diagnosis of prior candidal infection with HS after CO2 AFR was made. The triamcinolone ointment was discontinued and clobetasol 0.05% cream applied twice daily to the papules was initiated. A punch biopsy specimen was obtained to confirm the diagnosis. Histopathologic examination showed a hypertrophic scar characterized by epidermal atrophy, follicular plugging, fibroplasia and angioplasia with dense collagen bundles replacing the dermis and extending into the platysma muscle (see Fig. 2 path). Three weeks later, the papules had completely resolved. Clobetasol cream was discontinued. Mild hypopigmenta- tion has persisted 3 months later. Patient #2 A 61-year-old Caucasian woman with Fitzpatrick photo- type I skin presented for treatment of acne scars on the cheeks and photodamage on the face and neck. Her past medical history was significant for a facelift (1994), traditional full-face ablative CO2 resurfacing (1996), and minimal access cranial suspension (MACS) face and neck lifts (June, 2008). The patient had successfully Fig. 1. Three weeks post-treatment with CO2 AFR followed by Er:glass non-ablative fractional resurfacing: multiple well- defined, firm pale papules in linear arrays along skin folds of the anterior neck consistent with HS are apparent on the neck of a 57-year-old woman (Patient 1). Fig. 2. Photomicrograph of a biopsy specimen from the right anterior neck of Patient 1 shows a hypertrophic scar charac- terized by epidermal atrophy, follicular plugging, fibroplasia, and angioplasia with dense collagen bundles replacing the dermis and extending into the platysma muscle (H&E, 4 magnification). 186 AVRAM ET AL.