Material and Method: Thirty-one hemifacial spasm patients were randomly assigned into the non-split injection sites group (injecting Botulinum toxin A to the zygomaticus major and risorius each) or split injection sites group with the same amount of Botulinum toxin A as the first method (injection Botulinum toxin A to the zygomaticus major and minor and risorius two injections each) The main outcomes are onset of improvement and effective duration of treatment.

Results: Fifteen patients were assigned to non-split injection sites group and 16 patients were assigned to split injection sites group. The median onset of improvement in non-split injection sites group and split injection sites group was 4.0 and 4.5 days, respectively (p = 0.984). The effective duration of treatment in the non-split injection sites group was 60.0 days and in the split injection sites group was 54.5 days (p = 0.582).

Conclusion: The splitting of injection sites did not significantly improve the efficacy of Botulinum toxin A in the treatment of hemifacial spasm.

Keywords: Botulinum toxin, Hemifacial spasm, Dysport®