To evaluate the clinical effect of total-model fractional CO₂ laser in the treatment of atrophic acne scar.

A retrospective analysis was performed on the clinical data of patients with atrophic acne scar treated by total-model fractional CO₂ laser(Deep FX+ Active FX+ CW) in Laser Aesthetic Center of Plastic Surgery Hospital, Chinese Academy of Medical Sciences from January 2017 to September 2019. CW mode and/or Active FX mode was used to fine grinding of the scar edge, and Active FX mode and Deep FX mode were used to scan the whole area acne scar involved. The treatment was performed 3-5 times with an interval of more than 3 months. Two attending physicians who were not involved in the study evaluated the photos of patients before treatment and 3-5 times after treatment with the Global Aesthetic Improvement Scale (GAIS) and the Echelle d’Evaluation Clinique des Cicatrices d’acne (ECCA). Acne scar and overall facial skin quality were assessed with GAIS, a total score of 1 to 3, with a score 1 indicating deterioration and a score 3 indicating significant improvement. The severity and density of acne scarring were assessed with ECCA, with the higher the score, the more severe it is. The international numeric rating scale (NRS) was used to rate the pain immediately after treatment (0-10 points), with 0 indicating no pain and 10 indicating extreme pain. Side effects such as the occurrence of crusts, erythema, pigmentation and acne-like rash were observed. SPSS 24.0 was used for statistical analysis, and the measurement data were expressed by Mean±SD. Paired t-test was used for ECCA scores before and after treatment, and P<0.05 was considered as statistically significant difference.

A total of 75 patients were included in this study, including 16 males and 59 females, aged 27.2±6.2 years (19-49 years). Among them, the improvement in acne scar and overall facial skin quality were excellent in 12 cases, significant in 34 cases, median in 24 cases and poor in 5 cases. GAIS score was 1.62±0.77. The ECCA score was 157.20±18.89 before treatment and 138.93±23.62 after treatment, showing significant difference (t=9.41, P<0.001). The pain score was 4.65±1.52 and disappeared spontaneously about 2-4 hours after operation. The scab stage was 6.65±0.89 days, and the erythema stage was 3.09±0.70 weeks. The post-inflammatory hyperpigmentation case occurred in 1.3% (1/75) and lasted for 4 months. Acne-like rash occurred in 16.0% (12/75), which relieved by external smear of fusidic acid. No blisters, hypopigmentation, bacterial or viral infection, scar formation and other adverse reactions happened.

The total-mode fractional CO₂ laser is effective and safe in the treatment of facial atrophic acne scar.

Lasers, gas; Acne; Depressed scar; Fractional CO₂ laser