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An optimized abnormal muscle response recording method for intraoperative monitoring of hemifacial spasm and its
Chuyi Huang1, Suhua Miao2, Heling Chu3
1Clinical Neuroscience Institute, Yuquan Hospital, Medical Center, Tsinghua University, No. 5 Shijingshan Road, Shijingshan District, Beijing, 100040, China; Department of Neurology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200030, China.
Insights
Optimized intraoperative monitoring for microvascular decompression (MVD) in hemifacial spasm (HFS) improves surgical outcomes. This enhanced abnormal muscle response (AMR) method increases remission rates and reduces delayed recovery, offering a more accurate assessment of decompression effectiveness.
Area of Science:
- Neurosurgery
- Electrophysiology
- Neurology
Background:
- Intraoperative electrophysiological monitoring is crucial for assessing decompression sufficiency during microvascular decompression (MVD) for hemifacial spasm (HFS).
- Identifying the precise offending vessel can be challenging, sometimes leading to suboptimal surgical outcomes.
- Optimized abnormal muscle response (AMR) monitoring offers a potential improvement for MVD procedures.
Purpose of the Study:
- To evaluate the efficacy of an optimized abnormal muscle response (AMR) monitoring technique during microvascular decompression (MVD) for hemifacial spasm (HFS).
- To compare the outcomes of MVD using traditional versus optimized AMR monitoring methods.
- To assess the accuracy of continuous intraoperative monitoring in predicting decompression effectiveness.
Main Methods:
- Retrospective analysis of 2161 patients undergoing MVD for HFS.
- Comparison between traditional (1023 patients) and optimized (1138 patients) AMR monitoring methods.
- Modified AMR monitoring involved stimulating the zygomatic branch and detecting responses in multiple facial nerve branches.
Main Results:
- The optimized AMR method yielded higher relief rates at 1 day (95.1% vs. 92.2%), 3 months (97.4% vs. 95.0%), and 1 year (99.3% vs. 97.8%) compared to the traditional method.
- Significant differences were observed in immediate remission and 12-month recovery rates between the two groups (P < 0.05).
- Optimized monitoring demonstrated high sensitivity (95.7%-97.3%) and accuracy (93.1%-97.4%) in predicting HFS relief post-operation.
Conclusions:
- Optimized AMR monitoring enhances the detection rate of abnormal muscle responses and improves the accuracy of predicting decompression effectiveness.
- Utilizing optimized intraoperative monitoring during MVD for HFS leads to increased immediate remission rates.
- This approach effectively reduces the incidence of delayed recovery in patients with hemifacial spasm.
Background:
Intraoperative electrophysiological monitoring is used to determine whether decompression is sufficient during microvascular decompression (MVD) for hemifacial spasm (HFS). However, the real offending vessel is sometimes neglected by the neurosurgeons. Here, we reported our experience in using optimized abnormal muscle response (AMR) monitoring and continuous intraoperative monitoring for MVD.
Methods:
This study included 2161 HFS patients who underwent MVD using traditional (1023 patients) and optimized (1138 patients) methods. Modified AMR monitoring was adopted in our study, with the zygomatic branch of the facial nerve stimulated and the temporal branch, buccal branch, marginal mandibular branch and cervical branch of the facial nerve detected for AMR. These cases were analyzed retrospectively with emphasis on the postoperative outcomes and intraoperative findings. The therapeutic effect was evaluated at day 1, month 3 and year 1 after operation.
Results:
The relief rate at day 1, month 3 and year 1 after operation for patients who employed optimized AMR recording method was 95.1%, 97.4% and 99.3%, comparing with 92.2%, 95.0% and 97.8% in traditional method. There was significant difference in achieved immediate remission and recovery rate during 12-month follow-up between the two groups (P < 0.05). The modified intraoperative monitoring showed the sensitivity of AMR disappearance to judge the relief at day 1, month 3 and year 1 after HFS operation was 95.7%, 96.3% and 97.3%, respectively; the specificity was 44.6%, 43.3% and 50.0%, respectively; the accuracy was 93.1%, 94.9% and 97.4%, respectively.
Conclusions:
Our findings demonstrated that the optimized method could improve the positive detection rate of AMR and accuracy of decompression effect prediction. The evaluation for the decompression effect by optimized intraoperative monitoring can increase the immediate remission rate and reduce the delayed recovery rate.
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