ABSTRACT
BACKGROUND: Facial scars are mainly caused by trauma or surgery, which greatly affect the appearance. Dermatologists and plastic surgeons have tried many ways to change the appearance of scars. Botulinum toxin A injection is widely used in clinical practice for prevention of scars, but the efficacy and safety are not proved. OBJECTIVE: To evaluate the effectiveness and safety of botulinum toxin A injection in the prevention of facial trauma or postoperative hypertrophic scar. METHODS: PubMed, EMbase, the Cochrane library, CNKI, CBM, WanFang, and VIP were searched for randomized controlled trials regarding botulinum toxin A injection in the prevention of facial scars. Manual retrieval was done for supplement of incomplete data. Two doctors were responsible for literature screen and evaluation. Finally, 11 randomized controlled clinical trials were included. The experimental group was injected with botulinum toxin A, and the control group was given saline or nothing. Part of the data was analyzed using Revman 5.3 software for meta-analysis, and the data that could not be analyzed using software were subjected to a descriptive analysis. RESULTS AND CONCLUSION: Eleven randomized controlled trials were included, involving 436 patients with 518 wounds. Meta-analyses showed that Vancouver scar scale score, visual analogue scale score and width of scars in the botulinum toxin A group were significantly better than those in the control group (weighted mean difference (WMD)=-1.61, 95% confidence interval (CI)=-2.06 to -0.26, P = 0.02; WMD=1.7, 95%CI=0.38 to 3.02, P = 0.01; WMD=-0.17, 95%CI=-0.22 to -0.12, P < 0.000 1). Incidence of adverse reactions of botulinum toxin A group was higher than that in the control group (χ2 =8.335, P=0.004), but they were all slight and easy to release. There were no serious adverse events in both groups. It seems that botulinum toxin A injection can reduce the width of scars, improve Vancouver scale and visual analogue scale scores. However, it is suggested to make clear communication before and after the operation and take measures to deal with various adverse reactions in advance.