LAUSR

Context: Based on various Botulinum toxin A products, reports of the lower efficacy of Incobotulinum toxin A compared with Onabotulinum toxin A for muscle contouring were observed. In addition, complications of trapezius myalgia and shoulder contouring treatment from malpractice have been reported. Aims: The study aimed at comparing the efficacy between Incobotulinum toxin A and Onabotulinum toxin A; research was conducted on a safe treatment technique for trapezius hypertrophy and trapezius myalgia. Materials and Methods: A split-shoulder, double-blind, randomized controlled trial was performed. Twenty volunteers with trapezius hypertrophy and trapezius myalgia were randomly injected with 30 units of Incobotulinum toxin A and Onabotulinum toxin A in each trapezius muscle guided by ultrasound. Results: The trapezius thickness among those receiving treatment with Onabotulinum toxin A and Incobotulinum toxin A on day 60 was 7.35 ± 1.11 and 7.33 ± 1.21 mm, respectively, which did not portray a significant difference (P = 0.991). Compared with the muscle size from day 60 to one year, the size of the trapezius muscle that had been treated by Onabotulinum toxin type A regained a significantly larger size compared with that treated by Incobotulinum toxin A (P = 0.027). On comparing the size of the trapezius muscle treated by Incobotulinum toxin A between one year and day 0, it was observed that the trapezius thickness at one year had significantly decreased (P < 0.001). On comparing the pain score from day 60 to day 0, it was observed that the pain scores of trapezius myalgia treated by Onabotulinum toxin A and Incobotulinum toxin A significantly differed (P = 0.003). Conclusions: Incobotulinum toxin A had the same efficacy but a longer lasting effect for the trapezius size contouring and a higher efficacy for trapezius myalgia treatment compared with Onabotulinum toxin A.