Multimodal Scar Prevention Using Botulinum Toxin Type A, Fractional CO2 Laser, and Topical Silicone: A Randomized Split-Scar Clinical Trial

BACKGROUND: Scar formation is a common consequence of surgical and traumatic wounds. Although botulinum toxin Type A (BTX-A), fractional CO2 laser (fCO2L), and topical silicone cream (TSC) are widely used for scar modulation, evidence regarding their combined use remains limited. OBJECTIVES: The aim of the study was to evaluate combined BTX-A, fCO2L, and TSC compared with BTX-A+TSC, fCO2L+TSC, and TSC alone using a randomized split-scar design. METHODS: Thirty-six patients with head and neck wounds were enrolled in an assessor-blinded, randomized split-scar trial. Each scar half received either combination therapy (BTX-A+fCO2L+TSC) or a comparator treatment (BTX-A+TSC, fCO2L+TSC, or TSC). Scar outcomes were assessed using the Patient and Observer Scar Assessment Scale (POSAS) at baseline, 1, 3, and 6 months and the SCAR-Q Appearance, Symptoms, and Psychological Impact scales at baseline and 6 months. Linear mixed-effects models were used for statistical analysis. RESULTS: All groups improved over time (all P < .001). At 6 months, the combination group achieved the lowest Observer Scar Assessment Scale (10.33 ± 1.42) and Patient Scar Assessment Scale (8.11 ± 1.06) total scores (all P < .001 vs comparators) and the highest SCAR-Q scores across all domains. Both dual-modality regimens outperformed TSC. Although BTX-A+TSC and fCO2L+TSC showed comparable POSAS outcomes, BTX-A+TSC achieved higher SCAR-Q Appearance and Psychological Impact scores. Significant treatment, time, and treatment × time effects were observed across all outcomes (all P < .001). No serious adverse events occurred. CONCLUSIONS: Combined BTX-A, fCO2L, and TSC produced better clinician- and patient-reported scar outcomes compared with dual-modality regimens or TSC alone.