A prospective study of the effect of botulinum toxin A on masseteric muscle hypertrophy with ultrasonographic and electromyographic measurement.
We evaluated the effect of botulinum toxin A on masseteric muscle hypertrophy by using ultrasound and electromyography. Five patients (four with bilateral and one with unilateral masseteric muscle hypertrophy) were studied prospectively. In each patient, ultrasound-guided percutaneous intramuscular injection of botulinum toxin A was carried out. The change in muscle bulk was evaluated using serial ultrasonography and the electrical activity was assessed with electromyography. All five patients (nine hypertrophic muscles) showed a good response, with the maximal effect of a 31% reduction in muscle bulk seen 3 months after treatment. The effect remained stable one year after injection for six of the hypertrophic muscles, whereas three muscles needed a second injection to maintain the atrophy. This preliminary prospective study suggests that botulinum toxin A is a safe alternative method of treating masseteric muscle hypertrophy. However, the effect may be temporary and further intramuscular injection may be required to maintain atrophy.
To
E W
EW
Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, ROC.
Ahuja
A T
AT
Ho
W S
WS
King
W W
WW
Wong
W K
WK
Pang
P C
PC
Hui
A C
AC
D000293:Adolescent; D000328:Adult; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D004576:Electromyography; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000188:drug therapy; D007273:Injections, Intramuscular; D008297:Male; D008406:Masseter Muscle / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology*; D011446:Prospective Studies; D012008:Recurrence; D014463:Ultrasonography
D019274:Botulinum Toxins, Type A