Ablative Fractional Resurfacing for Chronic Wounds from Traumatic Scarring: A Case Report and Literature Review.

Ablative fractional resurfacing (AFR) can be utilized to improve scar appearance, texture, pain and associated contractures. Non-healing ulcers can also develop in areas of scarring and, in some cases, AFR can be utilized to heal these chronic wounds. We present a case of scarring with non-healing ulceration refractory to wound care, debridement and hydrotherapy successfully healed in four sessions with AFR using a 2940 nm Er:YAG laser. We review the literature on AFR for wound healing including potential mechanisms. AFR can be considered for non-healing ulcers in areas of scarring, once malignancy and infection are ruled out, and has the potential to provide relief for these suffering patients.J Drugs Dermatol. 2020;19(11): doi:10.36849/JDD.2020.5444.


INTRODUCTION
T he efficacy of lasers for scar treatment is well documented and multiple lasers are known to improve scars. Ablative fractional resurfacing (AFR) can be especially beneficial to improve scar appearance, texture, pain and associated contractures. 1 AFR is performed with carbon dioxide (CO 2 ) and erbium yttrium aluminum garnet (Er:YAG) lasers with water as the target chromophore.
Fractional photothermolysis works by creating columns or microthermal treatment zones (MTZs) of controlled thermal in jury with a grid-like pattern at an operator-determined depth and density. 2 The clinician can target the approximate depth of the scar and make depth and density adjustments based on body location as well as scar characteristics. The healthy skin between the MTZs facilitates a rapid wound healing response contributing collagen reconstruction and scar remodeling. 3 The ablated pinholes from AFR also relax skin contractures, pro moting improvement, some immediate, in areas of tension.• · 5 The open MTZs also can act as channels for topical drug deliv ery, which can be used to enhance treatment and achieve less painful more uniform distribution of drugs. 6 AFR has been established as the first line method for the treatment for traumatic scars in many centers.1.a Multiple studies have consistently documented significant subjective and objective improvements in scar appearance, color, height, texture, pliability, restriction, pain and itch, as well as an overall improvement in quality of life.a Most experts agree that AFR is the most effective overall laser platform for traumatic scars.a Non-healing ulcers can develop in areas of scarring. Previous reports have demonstrated success treating select chronic ulcers in the presence of scar contractures with AFR, citing decreased tension from improved scar pliability and texture, along with potential wound debridement, biofilm disruption, and molecular changes in the skin. 1 · 9 ·1 3 We present a case of traumatic scarring with non-healing ulceration treated with AFR to facilitate wound healing and then review the literature on this indication for AFR.

CASE REPORT
A 69-year-old obese and hypertensive female presented with a two-year history of multiple chronic, non-healing ulcers on the central abdomen with surrounding scarring refractory to standard wound care. Four years prior, a dermatitis of unspecified etiology developed, and ulceration occurred. The cause of the ulceration was unclear but pruritus and aggressive scratching were thought to have contributed per chart review. Months later, she underwent an Oasis ® grafting procedure. The graft became pruritic and the wounds returned, grew in size, and became increasingly painful. Biopsies were performed to rule out malignancy, fungal infection, and vasculitis. The wounds were repeatedly infected and did not respond to wound care, debridement, or hydrotherapy.
After multiple cycles of wound-improvement and recurrence, the wound-care specialist referred the patient for AFR in an effort to assist with wound healing. On physical exam, multiple open erosions on the central abdomen ranging from 1 to 3 cm in size were present with surrounding contracted scar tissue measuring about 8 cm x 5 cm. After evaluation, we proceeded with AFR using a 2940 nm Er:YAG laser (Sciton, Profractional, Palo Alto, CA). Prior to each laser application, the treatment area was topically anesthetized for 1 hour, cleaned

DISCUSSION
Lasers are known to improve scars and are commonly used by dermatologic, plastic and burn surgeons to decrease scar associated morbidity. 1 • AFR was first introduced in 2007 and has subsequently become widely accepted as a first-line treatment for traumatic scarring.1.s We report a case where AFR was used to mitigate scarring and heal a chronic ulcer refractory to other treatments. Complete healing of the chronic wounds was achieved.
Prior works (Table 1) have evaluated AFR for the healing of chronic wounds. '· 9 ' 2 Cases presented by Uebelhoer et al and Shumaker et al included severe scarring, contractures, and chronic nonhealing wounds from burns' and an explosive device blast 9 refractory to split-thickness skin grahing, physical therapy, and proper wound care. The scars on both patients were treated with CO 2 AFR using fluences ranging from 17.5 to 50 mJ and densities between 5 and 15%. The chronic wounds were treated with lower fluences and 3 to 5 weeks after a single AFR treatment, the ulcers in these patients were completely re epithelialized. Another 3-patient case series by the same group included nonhealing wounds and severe scarring after explosive device injuries and reported complete reepithelization after AFR.
Additional case reports have been published on nonhealing wounds in elderly patients, resulting from trauma and Mohs micrographic surgery, that responded to AFR. 1 1 Laser parameters included 30 mJ of energy at 5% density applied to the base of the wounds and 50 mJ to the surrounding skin for only one treatment, and complete healing was observed after 3 to 6 weeks, including in one diabetic patient." In another pilot C 0 study, ultrapulsed CO 2 laser at 4J was administered weekly to nine patients with diabetic ulcers with exposed bone.' 5 After a maximum of six treatments, four patients completely healed, one developed granulation tissue, three did not heal, and one underwent minor amputation. ' 5 In the same study with the same treatment parameters, AFR was combined with platelet rich plasma for the treatment of diabetic foot ulcers with The method of wound closure prompted by AFR warrants exploration. One theory is that AFR allows local relaxation of tissue and perhaps generation of additional collagen, relaxing tension in the scar area and allowing chronic wounds to close.
By improving the pliability of the surrounding skin, oxygen circulation to the wound may also be increased, fostering more rapid healing. 11 Other theories suggest AFR of chronic wounds exerts mechanical effects, stimulates collagen remodeling and triggers angiogenesis to activate a more effective wound healing process. ' 6 AFR has shown efficacy in the treatment of acute induced wounds in diabetic mice, more effectively reducing the size of the original wound when compared to natural healing." In this study, treatment groups exhibited significantly increased vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) mR NA expression with reductions in the expression of transformation growth factor-13 (TGF-13) mRNA.11 It is important to note that not every non healing ulcer in an area of scarring would be a good candidate for laser treatment. Malignancy and infection need to be ruled out with appropriate techniques, including biopsy and culture. The potential contribution of vascular compromise must also be considered. However, once other contributing factors are explored, then AFR may be considered.
AFR has revolutionized scar treatment and, as demonstrated by this case and review, can benefit select patients with chronic wounds in the setting of scarring. AFR should be considered for non-healing ulcers in areas of scarring, as it can provide the potential for relief for these suffering patients.

CONCLUSION
AFR can be considered for non-healing ulcers in areas of scarring, once malignancy and infection are ruled out. There are multiple theories regarding the mechanism of action, but further investigation is warranted.