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Clinical Trial to Evaluate the Efficacy of Botulinum Toxin Type A Injection for Reducing Scars in Patients With Forehead Laceration

Kim, Seong Hwan MD; Suh, In Suck MD, PhD; Jeong, Hii Sun MD, PhD; Lee, Seong Joo MD; Lee, Jun Won MD

Plastic and Reconstructive Surgery - Global Open: August 2019 - Volume 7 - Issue 8S-1 - p 4-5
doi: 10.1097/
Aesthetic Abstracts

Kangnam Sacred Heart Hospital, Seoul, Korea, Republic of (South)

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Skin damage by either trauma or surgical intervention inevitably results in scar formation. Facial scars can be cosmetically disfiguring and may cause functional impairment and psychosocial withdrawal. Botulinum toxin type A (BoNTA) is known to prevent fibroblast proliferation and expression of transforming growth factor-β1. It also induces temporary muscle paralysis and decreases tension vectors. Fibroblasts induce scar contracture and hypertrophy by producing collagen fibers in wound healing processes. In theory, botulinum toxin can play a vital role in scar prevention by reducing contracture and relaxing the adjacent muscles. Several studies have suggested the possibility of injecting botulinum toxin into nearby musculature around the traumatic or incisional wounds. However, sound clinical evidence has been missing. The aim of this study is to investigate the subjective and objective evidence of the effect that botulinum toxin has on scar formation in human. This is a prospective, split-scar, double-blinded, randomized controlled study. From February 2012 to December 2015, patients who presented forehead lacerations were recruited from the emergency room. Forty-five patients with forehead laceration were enrolled in this study and randomized into 2 groups with or without injection of BoNTA. When the patients presented to the clinic to remove the stitches, BoNTA was injected to the BoNTA group with 24 patients and saline was injected to the control group with 21 patients. The BoNTA was injected on dermal layer with 5 units/cm within a 0.5 cm distance on BoNTA group. Placebo drug was prepared as a vial containing 0.9% saline which is similar to BoNTA. After that, follow-up was done in 1, 3, and 6 months. The scars were analyzed with the Patient and Observer Scar Assessment Scale, Stony Brook Scar Evaluation Scales, and Visual Analog Scale and analyzed with independent t test, along with clinical photographs, cutometer, and biopsies. There were 21 patients in the control group and 24 patients in the BoNTA group. There were no significant adverse events in all patients. In all scar scales, the scores changed into favorable direction in both groups and the changes were larger in BoNTA group compared with the control group. However, when the amount of changes of the scar scales was investigated, there were more favorable changes in BoNTA group, which was proved statistically in Stony Brook Scar Evaluation Scales (P = 0.047) and Visual Analogue Scale (P = 0.046). Even without statistical significance, there were more favorable changes in BoNTA group in Patient Scar Assessment Scale (P = 0.110) and Observer Scar Assessment Scale (P = 0.169). Skin biopsy showed less collagen deposition on dermal layer in BoNTA group. In hematoxylin and eosin stain and Masson-trichrome stain, there was a denser deposition of collagen fibers of the specimen belonging to the control group compared to the BoNTA group. Based on the findings above, BoNTA can improve scar properties in various aspects, especially in decreasing collagen synthesis. The gross findings also showed favorable changes. This study provides useful indication of application of BoNTA in scar prevention with promising results.

Copyright © 2019 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons. All rights reserved.