Application of EMG monitoring to microvascular decompression for hemifacial spasm

HUANG Jin; WU Xiang-kui; ZHANG Yan-song; SHAO Jun-fei

doi:10.13798/j.issn.1009-153X.2016.03.011

Abstract：Objective To explore the applied value of intraoperative electromyography (EMG) monitoring to microvascular decompression for hemifacial spasm. Methods The clinical data of 72 patients with hemifacial spasm, who underwent microvascular decompression under intraoperative EMG monitoring, were analyzed retrospectively. The real-time recording of EMG response of facial muscles was performed by the needle electrode put into the ipsilateral orbicularis oculi muscle, orbicularis oris muscle and masseter. Intraoperative careful identification and treatment of vessels responsible for hemifacial spasm in order to understand the effect of decompression and objectively evaluate the prognoses of the patients. Results The blood vessels responsible for the hemifacial spasm were definitely determined in 60 patients. The arachnoid adhesion or thickening was found in 6 patients. The occult blood vessels probably were the vessels responsible for the hemifacial spasm in 6 patients. The abnormal EMG waveforms completely disappeared in 54 patients, almost disappeared in 16 and were unchanged in 2 after the decompression. The clinical symptoms disappeared completely in 57 patients, partly in 14 and were unchanged in 1 after the decompression. The overall effective rate was 98.6%(70/72). Conclusion The facial EMG monitoring is helpful to the intraoperative evaluation of the effect of decompression on the hemifacial spasm and the prognoses in the patients with hemifacial spasm. EMG monitoring plays an important guiding role in the microvascular decompression for hemifacial spasm, which especially caused by occult blood vessel.