Botulinum Toxin Type a Injection to Prevent Keloid Recurrence

Continuous variables will be reported as the mean ± standard deviation(SD). Each aspect of the VSS score, POSAS score, and the Cutometer parameters of each scar half between the BTA and control groups will be analyzed longitudinally using the paired t test. The interrater consistency will be evaluated using the Spearman rho. All analyses will be performed with IBM SPSS Version 23.0 (IBM Corp., Redmond, Wash.). A value of p \< 0.05 is considered to indicate statistical significance. The sample size was calculated based on the results of the investigators' aforementioned study published in 2019. Thirty patients underwent keloid revision and then received radiation therapy based on our treatment protocol. The postoperative Vancouver Scar Scale score was 4.15 ± 1.74. If treatment could improve VSS score by 1, which was considered clinically significant, approximately 26 patients would have been necessary to provide a result with a real significance (using the same SD and considering the standard α error of 0.05 and a power of 0.8). Assuming a 20% non-compliance rate for follow-up evaluation, the sample size was increased to 32 patients.