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

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.

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.

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.

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.

Combined BTX-A, fCO2L, and TSC produced better clinician- and patient-reported scar outcomes compared with dual-modality regimens or TSC alone.

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