New Technology: Compound Abnormal Muscle Response During Microvascular Decompression for Hemifacial Spasm

Area of Science:

• Neurosurgery
• Neurology
• Intraoperative Monitoring

Background:

• Hemifacial spasm (HFS) is a neurological disorder characterized by involuntary contractions of facial muscles.
• Microvascular decompression (MVD) is a surgical treatment for HFS, aiming to alleviate pressure on the facial nerve.
• Intraoperative monitoring is crucial for assessing nerve function during MVD.

Purpose of the Study:

• To evaluate the effectiveness of intraoperative compound abnormal muscle response (AMR) monitoring compared to single AMR monitoring during MVD for HFS.
• To determine the diagnostic accuracy and clinical utility of compound AMR in predicting surgical outcomes for HFS.

Main Methods:

• Eighty-six patients with HFS undergoing MVD were included in the study.
• Both single and compound AMR monitoring techniques were employed during surgery.
• Compound AMR involved recordings from multiple facial muscles (orbicularis oris, mentalis, frontal, orbicularis oculi) with electrical stimulation of facial nerve branches.
• Clinical outcomes were correlated with intraoperative AMR findings.

Main Results:

• Compound AMR monitoring successfully recorded responses in 42 out of 45 patients, while single AMR recorded in 34 out of 41 patients.
• Complete resolution of HFS was observed in 41 patients with compound AMR and 26 patients with single AMR.
• Compound AMR demonstrated a sensitivity of 96.3% and specificity of 97.2%, outperforming single AMR's sensitivity of 97.1% and specificity of 86.3%.

Conclusions:

• Compound AMR monitoring is a more suitable and accurate method than single AMR for intraoperative assessment during MVD for HFS.
• The higher specificity and sensitivity of compound AMR suggest its improved reliability in predicting successful surgical outcomes for HFS.