The Efficacy of Botulinum Toxin Type A (BTA) in the Treatment of Hypertrophic Scars and Keloids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Hypertrophic scars cause significant physical and emotional discomfort. Botulinum toxin type A (BTA) has shown promising outcomes in reducing scar formation. Research suggested its effectiveness in managing hypertrophic scars and keloids. This systematic review and meta-analysis were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, including randomized controlled trials (RCTs). The included studies involved patients with hypertrophic scars treated with BTA. Five databases were searched from inception to August 2024. Studies were screened and selected by two independent reviewers. Data on study design, patient demographics, and interventions was extracted. The risk of bias (ROB) was assessed using the ROB revised tool developed by Cochrane (ROB2). Meta-analysis was performed using RevMan Web (The Cochrane Collaboration, London, UK) with a random-effects model due to high heterogeneity, calculating mean differences for the primary and secondary outcomes. Outcomes included Vancouver Scar Scale (VSS) scores, scar thickness, vascularity, pliability, and pigmentation. The systematic review identified 182 records from five databases. The screening process resulted in seven studies included in the final analysis after assessment for eligibility. The efficacy of BTA in treating hypertrophic scars and keloids was assessed. The meta-analysis showed that BTA significantly improved VSS scores, with a pooled mean difference of -1.69 (P = 0.01). However, BTA did not show a statistically significant effect on reducing scar height/thickness or improving vascularity. Scar pliability was significantly improved by BTA, with a pooled mean difference of -0.76 (P = 0.002), while there was no significant effect on pigmentation. High heterogeneity was observed across the studies. BTA could be used as an effective treatment for the components of hypertrophic scars and keloids, especially regarding their pliability and improving scar quality. However, for functions such as the change in scar height, vascularity, and pigmentation, more research is still required among larger RCTs. Future research should focus on refining the treatment regimens and the mode of action of BTA to the scar tissue.