The value of abnormal muscle response monitoring during microvascular decompression surgery for hemifacial spasm

Abstract

Background and objectives Abnormal muscle response (AMR) to the electrical stimulation of a branch of facial nerve is a specific electrophysiological feature of primary hemifacial spasm (HFS). The aim of this study was to evaluate the value of AMR monitoring during microvascular decompression surgery (MVD), and the correlation between the AMR changes and the clinical outcomes. Methods This study included 241 cases of MVDs. Intraoperative AMR monitoring was performed for each subject. The patients were divided into two groups based on whether the AMR-disappeared or not following decompression of the facial nerve. Results Postoperatively, 229 (95.0%) patients were relieved from the spasm, 215 (93.9%) occurred in the AMR-disappeared group, 14 (6.1%) in the non-AMR-disappeared group. The correlation between intraoperative AMR abolition and HFS relief was statistically significant. Conclusions Intraoperative AMR monitoring was an effective assistant for a successful MVD for the patient with HFS. It is worth being routinely employed during the operation.