Prospective evaluation of incobotulinumtoxinA in the management of the masseter using two different injection techniques.

[BACKGROUND] IncobotulinumtoxinA (Xeomin Cosmetic) has been used previously in the management of masseteric hypertrophy. However, a standardized injection technique has not been established. The goal of the present study was to evaluate the efficacy and safety of two injection techniques in the management of masseteric hypertrophy using incobotulinumtoxinA.

[METHODS] Thirty female patients with masseteric hypertrophy were recruited and evenly randomized to receive bilateral treatments of either a single-injection technique (SIT) or a multiinjection technique (MIT). Improvement of masseteric hypertrophy was assessed at week 16 using standardized measurements and photographs. Patients completed a 5-point satisfaction questionnaire while physicians completed the Global Aesthetic Improvement Scale (GAIS) and 10-point photonumeric masseter prominence rating scale.

[RESULTS] There were no significant differences in physician ratings on the photonumeric scale and GAIS between the SIT and MIT groups. Results of the standardized measurements also revealed no significant difference between injection techniques. Majority of patients at every visit reported being "satisfied" with treatment results. Clinically, the number and severity of adverse events were similar between groups.

[CONCLUSION] This study supports the noninferiority of both SIT and MIT with regard to efficacy and safety in the management of masseteric hypertrophy, using incobotulinumtoxinA.