Retrospective analysis of non‐ablative scar treatment in dark skin types using the sub‐millisecond Nd:YAG 1,064 nm Laser

Abstract

The use of lasers to treat atrophic scarring conditions in darker skin types presents a significant challenge to laser practitioners. Current treatment modalities, including deep dermal peels; ablative; non-ablative; and fractional laser resurfacing and surgical techniques, are limited in skin types IV through VI due to increased risks of hyper- and hypo-pigmentation. This is especially true when attempting to treat large areas of acne scarring. This study investigates the treatment of atrophic scarring with a non-ablative sub-millisecond-pulsed 1,064 nm Nd:YAG laser in darker skin types. To evaluate the safety and efficacy of a sub-millisecond 1,064 nm Nd:YAG laser for the treatment of atrophic scarring in Fitzpatrick skin types III-VI through retrospective photographic analysis. A retrospective analysis was conducted of all patients (n = 22) who received sub-millisecond Nd:YAG laser treatments for atrophic scarring over a 6-month period. Patients had Fitzpatrick skin types III-VI and were treated for the indication of atrophic scarring using the fluence of 14-16 J/cm(2) , pulse duration of 300-500 microseconds and repetition rate of 5-7 Hz. An average of six treatments was performed on each patient approximately 3 weeks apart and the mean follow-up time after the final treatment was 9 months (range of 3-10 months). Blinded photographic assessments were performed by three independent physicians using photos unlabeled for before and after and arranged in non-chronological order. Reviewers were asked to determine before and after photos and the degree of improvement in scarring, textural change, and post-inflammatory hyper-pigmentation (PIH) secondary to the acne or scarring condition. Degree of improvement was graded using a four-point scale: 0 = <25%, 1 = 25-50%, 2 = 51-75%, 3 = 76-100%. Based on blinded photo assessments by three independent reviewers, clinically and statistically significant median improvement of 2 in scarring, 2.3 in texture, and 2 in pigment were observed (one-sample Wilcoxon signed rank test, P < 0.001). Reviewers were highly consistent (inter-reviewer reliability) in identification of before and after photos (kappa of 0.88). Preliminary data collected in this retrospective study suggest that sub-millisecond 1,064 nm Nd:YAG laser treatment is a safe and effective treatment for atrophic scarring in patients with darker skin types, delivering clinically and statistically significant results with reduced risk of pigment complications and patient discomfort.