The Impact of Botulinum Toxin on Scar Formation Following Thyroidectomy: A Systematic Review of Randomized Controlled Trials

Objectives: Thyroidectomy scars may lead to cosmetic issues as well as negative psychosocial effects in patients. . Botulinum toxin (BTA) is increasingly being used for facial scar reduction, but studies have also demonstrated its efficacy in treating thyroidectomy scars. The objective of this study is to systematically review studies in the literature on BTA for thyroidectomy scar formation. Methods: Five databases (PubMed, EMBASE, MedLine, Cochrane, and Web of Science) were searched in January 2025. Inclusion criteria were English-language randomized controlled trials that used scar assessment scales (Stony Brook Scar Evaluation Scale, Modified Stony Brook Scar Evaluation Scale, Vancouver Scar Scale) or patient subjective appearance. Exclusion criteria consisted of studies on using BTA for non-thyroidectomy scars and studies lacking follow-up data and outcomes on scar appearance. The search terms used were “thyroid*,” “thyroidectomy,” “parathyroid,” “parathyroidectomy,” AND “scar,” “scar management,” “wound healing,” “aesthetics,” “scar treatment.” Statistical analysis was performed in RStudio. Results: Six hundred forty-five articles were initially retrieved. Thirty-one articles were reviewed for full-text review. Four randomized controlled trials were finally included for a total of 125 patients. The age range of patients was 45 to 54 years old, and most patients were female (range: 73.3%–93.3%). Improvements in scar appearance were noted across various scar measurement scales such as the Stony Brook and Vancouver Scar Scales, and in patient satisfaction. Conclusions: Botulinum injections into the thyroidectomy incision may improve aesthetic scar outcomes based on several scar analysis scales. To the authors' knowledge, they provide the first review on the use of botulinum toxin on scar formation after thyroidectomy.