Low-dose subcutaneous injection of botulinum toxin type A for facial synkinesis and hyperlacrimation

Abstract

To investigate the efficacy of low dose of botulinum toxin type A (BTX-A) for facial synkinesis and hyperlacrimation. Eleven patients suffering from facial synkinesis after Bell's palsy or facial nerve injury were treated with a low dose of BTX-A, 0.5-1.25 U per point into several points. One patient showing hyperlacrimation was also treated with BTX-A. The whole observational period was 43 months. On average, 5.76 U of BTX-A, which was lower than that of previous reports, was injected per treatment. In seven cases, synkinesis disappeared completely after three or fewer sessions of BTX-A injection. The mean interval between treatments was 14.5 weeks. Hyperlacrimation was completely suppressed after a single subcutaneous injection of BTX-A. Only mild subcutaneous hemorrhage was observed as adverse reactions. Facial synkinesis can be treated with a lower dose of BTX-A without relevant adverse reactions.