Analysis of Multimodal Intraoperative Monitoring During Intramedullary Spinal Ependymoma Surgery

Area of Science:

• Neurosurgery
• Neurology
• Spinal Cord Monitoring

Background:

• Intramedullary spinal ependymomas require precise surgical techniques.
• Intraoperative monitoring using somatosensory-evoked potentials (SSEP) and motor-evoked potentials (MEP) is crucial for preserving neurological function.
• Evaluating the effectiveness of different monitoring criteria is essential for optimizing patient outcomes.

Purpose of the Study:

• To assess the diagnostic validity of SSEP and MEP monitoring during intramedullary spinal ependymoma surgery.
• To compare the efficacy of two warning criteria: 50% decline versus all-or-none.
• To determine the long-term predictive value of these monitoring techniques for up to six months post-surgery.

Main Methods:

• Retrospective analysis of 26 patients undergoing intramedullary spinal ependymoma surgery with SSEP and MEP monitoring.
• Evaluation of monitoring sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic odds ratio for each criterion.
• Postoperative neurological deficit assessment using the Medical Research Council scale and six-month follow-up.

Main Results:

• SSEP and MEP monitoring demonstrated high success rates (84.9% and 83.7%).
• The all-or-none criterion exhibited superior specificity, positive predictive value, and diagnostic odds ratio compared to the 50% decline criterion.
• SSEP validity was higher for upper extremities, while MEP was more effective for lower extremities; significant neurological improvement was observed in most patients within six months.

Conclusions:

• Intraoperative SSEP and MEP monitoring can yield false-positive and false-negative results, particularly in the immediate postoperative period.
• The all-or-none criterion provides a more reliable assessment of postoperative neurological status than the 50% decline criterion.
• The superior predictive performance of the all-or-none criterion is sustained for up to six months following surgery.