Efficacy and Safety of Botulinum Toxin Type A Injection in Patients with Bilateral Trapezius Hypertrophy.

[OBJECTIVE] To evaluate aesthetic outcomes in patients with bilateral trapezius hypertrophy treated by botulinum toxin type A (BTxA) injection for aesthetic reconstruction of the upper trapezius.

[METHODS] From May 2015 to May 2016, 30 women with a short neck shape resulting from bilateral trapezius hypertrophy were treated with botulinum toxin type A (BTxA) injection at the most affected area of the upper trapezius. Pre- and postoperative values of S (irregularly shaped area of the four points A, C, D, and F) and S (irregularly shaped area of the four points A, C, D, and E), responses to patients' and doctors' Global Aesthetic Improvement Scale (GAIS) questionnaires for neck aesthetic assessment, as well as reported adverse events, were recorded and analyzed.

[RESULTS] Duration of follow-up ranged from 4 to 12 months. Subjects experienced non-severe adverse events and complete recovery after a single BTxA injection. In patients' GAIS questionnaires, "very much improved" accounted for 53%, "much improved" accounted for 13%, and "improved" accounted for 27%. In doctors' GAIS questionnaires, "very much improved" accounted for 27%, "much improved" accounted for 33%, "improved" accounted for 33%, and "no change" accounted for 7%. The overall degree of improvement was high. Statistically significant differences were observed with respect to the "very much improved" response to GAIS questionnaires between patients and doctors (P = 0.035).

[CONCLUSION] A single injection of BTxA for aesthetic reconstruction of the upper trapezius is safe and effective in patients with bilateral trapezius hypertrophy.

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