Purpose

To evaluate the effect of botulinum toxin type A (BTX-A) on scar quality following direct brow lift using an intraindividual comparison with saline solution after six months of follow-up.

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Methods

This randomized, controlled, double-blind, intraindividual clinical trial included patients who received BTX-A on one side and an equivalent volume of 0.9% saline solution on the contralateral side between postoperative days 3 and 7. BTX-A (abobotulinumtoxinA, Dysport®, 500 U vial diluted in 3.5 mL saline) was injected exclusively along the scar length at a dose of 7.5 U every 2 cm. Scar quality at 180 days was assessed using the Patient and Observer Scar Assessment Scale (POSAS), Vancouver Scar Scale (VSS), Stony Brook Scar Evaluation Scale (SBSES), and Visual Analogue Scale (VAS). Statistical analysis was performed using linear mixed-effects models with patient-level random intercepts. The study was conducted in accordance with the Declaration of Helsinki and approved by the ethics committee.

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Results

Fifty-two patients were enrolled, and 46 completed follow-up and were included in the final analysis. Significant improvement in scar quality was observed on the BTX-A-treated side in the POSAS (β = -0.97; 95% CI: -1.36 to -0.58; p < 0.001), VSS (β = -0.50; 95% CI: -0.71 to -0.29; p < 0.001), and VAS (β = -0.43; 95% CI: -0.57 to -0.29; p < 0.001). In the SBSES, a higher score was observed on the treated side (β = 0.15; 95% CI: 0.00 to 0.30; p = 0.05). Effect sizes were small to moderate, with greater magnitude observed in the VAS and VSS.

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Conclusion

Early postoperative BTX-A application following direct brow lift improved scar quality at 180 days, with consistent evidence across multiple assessment scales. The observed effect demonstrated moderate magnitude and clinical relevance, particularly for facial scars.

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Additional Authors

First name	Last name	Base Hospital / Institution
Juliane	Rodrigues	University of São Paulo (USP)
Pandora	Fonseca	Federal University of Campina Grande
Carolina	Susanna	University of São Paulo (USP)
Janaína	Brabo	University of São Paulo (USP)
Rogério	Leal	University of São Paulo (USP)
Ivana	Pereira	University of São Paulo (USP)
Suzana	Matayoshi	University of São Paulo (USP)

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