Botulinum Toxin A for Improving Cosmetic Outcomes in Facial Wound Healing: A Systematic Review, Meta-Analysis, and Dose-Response Evaluation.

Abstract

Introduction: Facial wound healing often results in unsatisfactory scarring with significant aesthetic and psychological impact. Botulinum toxin A (BTX-A) has appeared as a promising intervention to improve cosmetic outcomes by reducing muscle tension during wound healing. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of BTX-A in facial wound management.

Methods: We conducted a detailed scientific literature database from inception to 15th of May, 2025, following PRISMA 2020 guidelines. All eligible studies comparing BTX-A with control interventions for facial wound healing were included. Primary outcomes were visual analog scale (VAS) scores and scar width measurements. Secondary outcomes included Vancouver Scar Scale scores, patient satisfaction, and adverse events. Meta-regression investigated dose-response relationships.

Results: Fifteen studies with total of 607 participants met inclusion criteria. Botulinum toxin A significantly improved VAS scores (standardized mean difference 0.87, 95% CI: 0.45-1.29, P-value<0.001) and reduced scar width by 0.35 mm (95% CI: -0.52 to -0.18, P-value<0.001). Meta-regression (R²=24%, P-value=0.032) demonstrated a dose-response relationship with effect size increasing by 0.08 SMD units per U/cm. The 5 to 15 U/cm range was identified through safety-efficacy modeling, where doses <5 U/cm showed suboptimal efficacy (SMD 0.65), 5 to 15 U/cm achieved optimal balance (SMD 0.78-1.18, adverse events 1.1%-6.2%), and >15 U/cm showed diminishing returns with increased adverse events. Adverse event rates were comparable between groups (3.9% versus 3.4%, P-value=0.75), with no serious complications reported.

Conclusions: Botulinum toxin A demonstrates significant efficacy in improving facial wound cosmetic outcomes with an excellent safety profile. Evidence-based dosing of 5 to 15 U/cm provides the best benefit-risk ratio. On the basis of cost-effectiveness evaluation of included studies, the intervention demonstrates favorable benefit-risk ratios for wounds in high-visibility facial areas, with economic modeling suggesting better utility for longer wounds where scar prevention outweighs treatment costs.