Microneedling Monotherapy for Acne Scar: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction: Acne scarring, formed by the deposition of collagen following inflammatory acne, not only represents a cosmetic problem but also poses a psychological health risk to patients. As microneedling has become a common treatment for acne scarring, an increasing number of studies have compared the efficacy and safety of microneedling. In this study, we conducted a meta-analysis of randomized controlled trials (RCTs) comparing microneedling with other treatments. Method: Three databases, namely Embase, PubMED, and Cochrane library, were searched until June 20, 2021, for RCTs only. Studies using microneedling in both treatments were excluded. Results: Twelve studies, totaling 414 participants, were included in our meta-analysis. For objective scar improvement, the pooled estimate analysis of the first group, treated with microneedling without radiofrequency, yielded a mean difference of 0.42 (95% CI—0.12–0.73%) with a significant difference at the 5% significance level. The second group, treated with fractional radiofrequency microneedling, exhibited no significance at the 5% significance level. Regarding subjective satisfaction, most results exhibited no significant difference between microneedling and other treatments. Although no case of secondary scarring or infection was reported in our study, the pooled result of postinflammatory hyperpigmentation was significant at the 5% significance level and preferred microneedling treatment. Conclusion: Microneedling without radiofrequency achieved superior results in terms of scar improvement. No form of microneedling caused postinflammatory hyperpigmentation—an advantage in acne scar treatment. Thus, microneedling is a favorable choice for the treatment of acne scarring. Level of Evidence III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.