Placebo-controlled double-blind cross-over study of botulinum A toxin in hemifacial spasm

The evaluation of the efficacy of botulinum A toxin injection for hemifacial spasm has never previously been done in a double-blind study in spite of its use as a treatment. We thus conducted a double-blind cross-over study of botulinum A toxin use in hemifacial spasm in 55 patients at Siriraj Hospital, Mahidol University, Bangkok, Thailand. Thirteen patients decided to withdraw from the study due to a lack of efficacy, all of them were subsequently found to be in the saline injection group. The remaining 42 patients, in the botulinum A toxin injection (30 mouse units) group, reported the responses as: excellent (34 patients; 80.95%), moderate patients; 2.38%). In contrast, when given the saline injection they reported no excellent outcome, 1 patient (2.38%) with moderate improvement, 5 patients (11.90%) with mild improvement and, 36 patients (85.71%) with no response. Side effects of botulinum toxin injections were found in 14.29% of patients compared with 9.5% of the saline injection group. The side effects of botulinum toxin injection were mild transient facial weakness (7.14%), local pain (4.76%) and excessive lacrimation (2.38%). We concluded that botulinum A toxin injection was a simple and effective out-patient treatment for the management of hemifacial spasm.