Lessons Learned Evaluating Ablative Fractional CO2 Laser for Burn-Related Donor Site Scars

Area of Science:

• Dermatology and Regenerative Medicine
• Burn Injury and Scar Management
• Laser Therapy in Dermatology

Background:

• Hypertrophic scarring (HTS) is a common sequela of burn injuries, often necessitating split thickness skin grafting (STSG), leading to symptomatic scarring at both grafted and donor sites.
• Ablative fractional laser resurfacing (FLSR) is utilized for HTS treatment, yet many studies lack adequate control sites and detailed tissue-level analysis.
• The ethical considerations of withholding FLSR from patients for research purposes complicate the design of randomized controlled trials (RCTs) for HTS.

Purpose of the Study:

• To evaluate the efficacy of FLSR in treating hypertrophic scars at STSG donor sites (DS) by randomizing these sites within a controlled trial.
• To compare FLSR treatment versus standard of care (SOC) for DS scars, assessing various physiological and clinical parameters.
• To determine if STSG donor sites are appropriate substitutes for burn scar (BS) HTS in RCT designs evaluating FLSR.

Main Methods:

• Twenty patients with STSG donor site scars received 6 FLSR treatments. Donor sites were randomized to receive either FLSR plus SOC or SOC alone.
• Pre-treatment and serial evaluations included trans-epidermal water loss (TEWL), melanin index (MI), elasticity, erythema, epidermal thickness, rete ridge ratio (RRR), and papillary dermal cellularity.
• Scar severity was assessed using the Patient and Observer Scar Assessment Scale (POSAS), Vancouver Scar Scale (VSS), and an institutional Scar Comparison Scale (SCS).

Main Results:

• Pre-treatment, donor sites (DS) and burn scars (BS) exhibited hyperpigmentation compared to normal skin (NS). BS showed reduced elasticity and increased TEWL versus NS.
• DS skin displayed increased cellularity, reduced RRR, and increased epidermal thickness compared to NS. Both patients and observers rated BS severity higher than DS scars.
• No significant differences were found between FLSR-treated DS and control DS in TEWL, elasticity, erythema, MI, cellularity, RRR, epidermal thickness, POSAS, VSS, or SCS scores over time. Patient-perceived improvement (decreased SCS) was noted across all scar types.

Conclusions:

• While NS and DS skin have physiological differences, they are not as pronounced as those between BS and NS. FLSR did not appear to alter the maturation rate of DS scars compared to SOC.
• The study suggests that STSG donor sites may not be adequate surrogates for burn scar HTS in RCTs due to differing pathophysiological characteristics.
• Future research should investigate extracellular matrix morphology and transcriptomics in donor site and burn scar healing to better understand laser treatment effects.