Early Postoperative Application of Botulinum Toxin Type A Prevents Hypertrophic Scarring after Epicanthoplasty: A Split-Face, Double-Blind, Randomized Trial

Background: Postoperative hypertrophic scarring of the medial canthal area is a common phenomenon and deterrent for patients considering epicanthoplasty. Botulinum toxin type A has been reported for hypertrophic scar and keloid treatment. However, there is a lack of high-level evidence regarding the effects of botulinum toxin type A in the medial canthal area. Methods: In this split-face, double-blind, randomized trial, 43 consecutive consenting patients undergoing Park Z-epicanthoplasty were randomized to receive 5 U of botulinum toxin type A or the same volume of saline injections at days 6 to 7 postoperatively. Scars were assessed independently using the Vancouver Scar Scale, the visual analogue scale, and patient satisfaction rating at the 1-, 3-, and 6-month follow-ups. Results: Overall, 30 patients completed this trial. The botulinum toxin type A-treated side achieved significantly improved Vancouver Scar Scale scores. The most obvious improvements were observed at the 3-month follow-up visit. Among the four subscores of the Vancouver Scar Scale, the most significantly improved subscores were the height and pliability. The visual analogue scale scores also decreased significantly on the botulinum toxin type A-treated side at all three follow-up visits. Approximately 86.7 percent of the patients were satisfied with the scar and epicanthoplasty outcomes. No severe complications were reported. Conclusions: Early postoperative botulinum toxin type A injection in the medial canthal region efficiently reduces hypertrophic scarring and improves the outcome of epicanthoplasty. Therefore, botulinum toxin type A injection can be used as a routine method to prevent hypertrophic scarring and improve the outcome of epicanthoplasty.