This randomized controlled trial examined the effects of botulinum toxin type A (BTXA) on postoperative hypertrophic scarring of the medial canthal area.

Study design

The authors performed a double-blind, split face, controlled trial on 43 consecutive patients undergoing Park Z-epicanthoplasty. Patients randomly received BTXA or saline on one side of the face at 6 to 7 days postoperatively. The BTXA and saline injections were administered subcutaneously at two sites (5U total BTXA; 2.5U in 0.05 ml/site): 0.2 cm away from the medial surgical wound edge and 1 cm above and 0.2 cm from the wound edge (aimed at the orbicularis oculi muscle and depressor supercilii muscle). Patients were assessed on the Vancouver Scar Scale (VSS), visual analogue scale and for satisfaction at 6 months postoperatively.

Outcomes

A total of 30 patients completed the study. The BTXA group showed improvement in scarring as early as 1 month. The VSS was most improved at 3 months in the height and pliability scores.

There was high patient satisfaction (86.7%) and patients felt the BTXA side was less tight than the control side. The visual analogue scale was also improved at all follow-up visits. After 6 months, the hypertrophic scars gradually regressed and the difference decreased. One patient had mild ptosis that recovered within 6 weeks.

Limitations

The study was designed and performed well, with double-blind, split face control between experimental and control. The amount of botulinum toxin applied was very small (0.05 ml of solution per site) and may have had some variation due to the small dose; otherwise, there was no significant weaknesses to this study.

Clinical significance

Surgeons should consider botulinum toxin injection at 1 week postoperatively to help prevent hypertrophic scarring in the medial canthal area. The beneficial effect is evident as early as 1 month and can last up to 6 months, especially in epicanthoplasty.