A practical framework for interpreting intraoperative electrophysiological signals in acoustic neuroma surgery.
- 1Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha 410008, China.
Abstract
Objective
To develop a practical, stepwise framework for interpreting intraoperative neurophysiological signals to predict facial nerve outcomes after acoustic neuroma surgery.Methods
This methodological report synthesizes evidence from three IONM modalities: facial motor evoked potentials (FMEPs), direct electrical stimulation (DES), and free-running electromyography (EMG). Key predictive parameters, threshold values, sensitivity, specificity, and technical limitations were extracted from published meta-analyses, systematic reviews, and prospective cohort studies. These parameters were then organized chronologically into a stepwise interpretation framework according to their typical intraoperative use.Results
An end-of-surgery FMEP amplitude reduction >50% predicts poor long-term (≥1 year) facial function with 93% specificity. A DES threshold ≤0.05 mA at the brainstem stump predicts good long-term function (73% sensitivity, 74% specificity). A cumulative A-train duration >10 s on free-running EMG signals high risk for severe immediate palsy (66.7% sensitivity, 88.0% specificity). The 2026 CNS guidelines confirm that electrophysiological parameters predict long-term outcomes better than clinical information alone.Conclusions
This report provides a clinically usable, stepwise framework that integrates FMEP, DES, and free-running EMG thresholds for intraoperative prediction of facial nerve function.Significance
Despite routine use of intraoperative neurophysiological monitoring, no standardized framework has existed to translate real-time signals into postoperative facial nerve predictions. This framework fills that gap by offering surgeons and monitoring teams a clear, evidence-based, and chronologically ordered decision aid, potentially improving early recognition of poor outcomes and facilitating timely referral for facial reanimation.
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BibTeX
@article{li2026practical,
title = {{A practical framework for interpreting intraoperative electrophysiological signals in acoustic neuroma surgery.}},
author = {Juan Li and Qing Liu and Xianrui Yuan and Jian Yuan},
journal = {Clinical neurophysiology practice},
year = {2026},
month = sep,
doi = {10.1016/j.cnp.2026.09.006},
url = {https://europepmc.org/article/MED/42898074},
note = {CC BY},
}
RIS
TY - JOUR
TI - A practical framework for interpreting intraoperative electrophysiological signals in acoustic neuroma surgery.
AU - Juan Li
AU - Qing Liu
AU - Xianrui Yuan
AU - Jian Yuan
PY - 2026
DA - 2026/09/29
JO - Clinical neurophysiology practice
DO - 10.1016/j.cnp.2026.09.006
UR - https://europepmc.org/article/MED/42898074
AB - Objective To develop a practical, stepwise framework for interpreting intraoperative neurophysiological signals to predict facial nerve outcomes after acoustic neuroma surgery.Methods This methodological report synthesizes evidence from three IONM modalities: facial motor evoked potentials (FMEPs), direct electrical stimulation (DES), and free-running electromyography (EMG). Key predictive parameters, threshold values, sensitivity, specificity, and technical limitations were extracted from published meta-analyses, systematic reviews, and prospective cohort studies. These parameters were then organized chronologically into a stepwise interpretation framework according to their typical intraoperative use.Results An end-of-surgery FMEP amplitude reduction >50% predicts poor long-term (≥1 year) facial function with 93% specificity. A DES threshold ≤0.05 mA at the brainstem stump predicts good long-term function (73% sensitivity, 74% specificity). A cumulative A-train duration >10 s on free-running EMG signals high risk for severe immediate palsy (66.7% sensitivity, 88.0% specificity). The 2026 CNS guidelines confirm that electrophysiological parameters predict long-term outcomes better than clinical information alone.Conclusions This report provides a clinically usable, stepwise framework that integrates FMEP, DES, and free-running EMG thresholds for intraoperative prediction of facial nerve function.Significance Despite routine use of intraoperative neurophysiological monitoring, no standardized framework has existed to translate real-time signals into postoperative facial nerve predictions. This framework fills that gap by offering surgeons and monitoring teams a clear, evidence-based, and chronologically ordered decision aid, potentially improving early recognition of poor outcomes and facilitating timely referral for facial reanimation.
SN - 2467-981X
ER -