A prospective study of the effect of botulinum toxin A on masseteric muscle hypertrophy with ultrasonographic and electromyographic measurement

• Published in: British journal of plastic surgery Vol. 54; no. 3; pp. 197 - 200
• Main Authors: To, Edward W.H., Ho, W.S., Wong, W.K., Pang, Peter C.W., Ahuja, Anil T., Hui, Andrew C.F., King, Walter W.K.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2001; Elsevier
• Subjects: Adolescent; Adult; Biological and medical sciences; botulinum toxin A; Botulinum Toxins, Type A - therapeutic use; electromyographic monitoring; Electromyography; Ent. Stomatology; Facial bones, jaws, teeth, parodontium: diseases, semeiology; Female; Humans; Hypertrophy - drug therapy; Injections, Intramuscular; Male; Masseter Muscle - diagnostic imaging; Masseter Muscle - drug effects; Masseter Muscle - pathology; masseteric muscle hypertrophy; Medical sciences; Non tumoral diseases; Otorhinolaryngology. Stomatology; Pharmacology. Drug treatments; Prospective Studies; Recurrence; Ultrasonography; ultrasound monitoring; electromyographic monitoring; botulinum toxin A; masseteric muscle hypertrophy; ultrasound monitoring; Sonography; Human; Enzyme; Masseter muscle; Metalloendopeptidases; Prospective; Electrodiagnosis; Peptidases; Bontoxilysin; Chemotherapy; Treatment; Echography; Hydrolases; ENT disease; Electromyography; Biological effect; Hypertrophy
• ISSN: 0007-1226; 1465-3087
• DOI: 10.1054/bjps.2000.3526

We evaluated the effect of botulinum toxin A on masseteric muscle hypertrophy by using ultrasound andelectromyography. 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.