Abstract

Intramedullary spinal cord tumors (IMSCTs) are rare yet highly morbid neoplasms, where surgical resection remains the primary treatment. However, preserving neurological function during surgery is paramount, necessitating the use of intraoperative neurophysiological monitoring (IONM). Among the commonly used IONM modalities, transcranial motor-evoked potentials (TcMEPs) recorded as muscle MEPs (mMEPs) and D waves provide real-time insights into corticospinal tract integrity. Despite their widespread use, their diagnostic accuracy in predicting postoperative motor deficits remains incompletely understood.

This systematic review and meta-analysis comprehensively evaluates and compares the diagnostic performance of mMEPs and D waves in predicting immediate, transient, and persistent postoperative motor deficits following IMSCT resection. A systematic literature search across PubMed, MEDLINE, and OVID databases (1985–2024) identified 26 studies, encompassing 1,079 patients. Sensitivity, specificity, and diagnostic odds ratios were analyzed using bivariate meta-analysis models, with postoperative motor outcomes serving as the reference standard.

Key findings revealed that mMEP monitoring demonstrated superior sensitivity in detecting immediate and transient postoperative deficits, identifying 23.1% of persistent deficits missed by D waves. However, D wave monitoring exhibited superior specificity across all deficit categories and was the most reliable predictor of persistent deficits, highlighting its critical role in assessing long-term motor outcomes. These results suggest that while D waves are valuable for predicting irreversible deficits, an overreliance on this modality alone may lead to missed transient or fine motor impairments.

This presentation will discuss the implications of these findings for neurosurgeons and neurophysiologists, emphasizing the necessity of a multimodal IONM approach. By integrating both mMEPs and D waves into surgical decision-making, surgeons can optimize intraoperative strategies to minimize neurological deficits and improve functional outcomes. Additionally, we will address the limitations of current monitoring techniques, institutional variations in neuromonitoring protocols, and future directions for enhancing IONM accuracy.

Our study underscores the complementary roles of mMEP and D wave monitoring, advocating for their combined use to refine intraoperative neuromonitoring strategies and enhance patient safety during IMSCT surgery.

What will audience learn from your presentation?

This presentation will explore the comparative accuracy of mMEPs and D waves in predicting immediate, transient, and persistent motor deficits, highlighting their strengths and limitations. It will demonstrate how combining both modalities enhances intraoperative decision-making, reduces postoperative deficits, and improves patient outcomes by preventing permanent neurological impairment. Additionally, the findings provide valuable insights for refining neuromonitoring protocols, guiding future research, and enhancing neurosurgical education. Finally, the study emphasizes the need for standardizing IONM practices to improve monitoring accuracy and develop reliable alarm criteria.

This presentation will help surgeons make informed decisions to prevent motor deficits, while neurophysiologists can improve monitoring accuracy and signal interpretation. Researchers and faculty can build upon these findings for future studies and teaching, and medical trainees will gain a deeper understanding of IONM’s critical role in neurosurgical safety.

Yes, this study provides a data-driven analysis of intraoperative neuromonitoring (IONM) techniques that faculty can use to enhance neurosurgical and neurophysiology education. It can also serve as a foundation for future research on refining alarm criteria, optimizing multimodal monitoring strategies, and improving intraoperative decision-making.

Yes, this research offers a practical solution by highlighting the complementary roles of mMEPs and D waves in preventing postoperative deficits. By integrating both modalities, neurosurgical teams can make more informed intraoperative decisions, ultimately improving patient safety and reducing long-term neurological impairments.

Yes, this study provides new information on the diagnostic accuracy of mMEPs and D waves, which can help refine IONM protocols and improve the reliability of intraoperative monitoring. The findings support a multimodal approach, ensuring better accuracy in detecting motor deficits and optimizing surgical outcomes.