Increasing the area and varying the dosage of Botulinum toxin a injections for effective treatment of hemifacial spasm.

CONCLUSION

Wider-area botulinum toxin (BT) injection with the dosage depending on specific pathology is a promising approach for the treatment of hemifacial spasm (HFS), resulting in effective and long-lasting control of HFS with fewer side-effects.

OBJECTIVE

The aim of this study was to develop a BT injection strategy that minimizes complications by considering the causes, duration, and electrophysiologic features of the disease, as well as the patient's age.

METHODS

From July 2011 to July 2015, 26 patients were included in the strategy. The mean age was 61.8 ± 14.6. In the case of essential HFS, 2 units/injection site was the standard dosage. If a patient was aged over 60 and had a reduced electromyogram (EMG) amplitude, the dosage was reduced by 0.5 units/site. In the case of post-paralytic and tumor-induced HFS, 1.5 units/site was the standard dosage. All cases were managed by alternating injections of Botox and Dysport with no physical therapy.

RESULTS

Most HFS patients treated with the injection strategy had complete remission of HFS within 1 week. The average number of BT injection sites was 22.6 ± 6.7. The mean total BT dosage on the affected side was 28.6 ± 4.9 units. The mean duration of BT efficacy was 28.6 ± 7.7 weeks.