Effectiveness of Botulinum Toxin-A on Face, Head, and Neck Scars: A Systematic Review and Meta-Analysis

Background: Botulinum toxin A (BTA) temporarily paralyzes nearby muscles to reduce tension in wound sites, inhibiting scar hyperplasia. Objective: To evaluate the effectiveness of BTA injection on scar formation and quality in various face, head, and neck sites. Methods: A comprehensive search was conducted across four electronic databases and registries to identify relevant studies. We assessed the following outcomes: visual analog scale (VAS), Vancouver scar scale (VSS), scar width, patient self-assessment scale, Stony Brook scar evaluation scales, Observer scar assessment scale, Manchester scar scale, and patient scar-assessment scale. Results: This systematic review included 20 studies encompassing 894 patients, of which, 18 studies were eligible for meta-analysis. The VAS and VSS significantly improved with BTA compared to controls which significantly reduced scar width at the first and second measurement points compared to controls. Subgroup analyses revealed that BTA had better upper lip and forehead outcomes. Conclusion: This systematic review and meta-analysis found that scars of the face, head, and neck were improved with BTA treatment compared to controls. This highlights the need for further study, especially concentrating on the upper lip and forehead regions, where improved outcomes were identified on subgroup analysis.