ABSTRACT
Objective:To evaluate the efficacy of botulinum toxin A injection therapy with ultrasound-guided for benign masseter hypertrophy.Methods:Twenty cases (40 sides) of masseter hypertrophy were injected with botulinum toxin A, among which 10 cases were taken as experimental group and the other 10 cases as control group. The experimental group had preoperative ultrasound examination to measure the thickness of masseter, and use ultrasound-guided precise injection during the operation, and then ultrasound recheck to measure the postoperative masseter thickness; The other 10 cases of control group adopt traditional 3-point injection method.Results:The masseter thickness of the two groups at different period of times after treatment was decreased ( P<0.001), the most obviously decrease happened 4-12 weeks after injection. The mean reduction was 26.8% at 4 weeks and 28.4% at 12 weeks after injection. Masseter muscle thickness recovered by 22% at 24 weeks and by 20% at 36 weeks. The average follow-up was 6.0±2.4 months with no serious complications occurred. In the control group, there was a partial masseter bulge in one case. The satisfactory rate of the patients in the experimental group was higher than that of the control group. Conclusions:Botulinum toxin A injection therapy with ultrasound-guided for benign masseter hypertrophy is an effective treatment, which is more accurate and effective than the traditional injection method.