A systematic review and meta-analysis on the effects of the ultra-pulse CO2 fractional laser in the treatment of depressed acne scars

Background: Acne is a chronic inflammatory disease that occurs in the sebaceous glands of the hair follicles. Depressed acne scars, also known as depressed scars, remain after recovery. Clinical treatments of depressed scars include chemical peels, surgical treatments, radio frequency treatments, and laser treatments. Ultra-pulse carbon dioxide (CO2) fractional laser treatment has become the main method for treating depressed scars in recent years, but there are no systematic reports on the effectiveness and safety of this treatment. Methods: English databases, including PubMed, Embase, and Ovid-Medline, were searched to retrieve relevant articles. The search period ran from the establishment of the databases to April 2021. The search terms included CO2 lattice laser, depressed acne scars, depressed scars, and effectiveness. Results: A total of 6 articles comprising 467 patients with depressed acne scars were included in the meta analysis. The results showed that patients treated with ultra-pulsed CO2 fractionated laser scored higher in skin smoothness compared to other methods [standard mean difference (SMD) =0.49, 95% confidence interval (CI): 0.13-0.84; P=0.008], and significantly higher total skin lesion scores (SMD =0.35, 95% CI: -0.00 to 0.70; P=0.05). Discussion: A total of 6 articles were included in this study on the clinical efficacy of the ultra-pulse CO2 fractional laser in the treatment of depressed acne scars. The study found that compared to other treatments, this laser had a better curative effect in terms of the effective rate and patient skin smoothness score.