Review of the Role of Intraoperative Neurophysiological Monitoring in Spinal Surgery With a Focus on the True and False Positives and a Clinical Correlation

Background: Spinal surgery is a technically challenging endeavor with potentially devastating complications. Intraoperative neurophysiological monitoring (IONM) is a method of preventing and identifying damage to the spinal cord. Objective: The aim of our study was to examine the clinical utility of IONM in spinal surgeries performed at our institution and what effect, if any, subsequent interventions had on postoperative patient outcomes. Methods: This is a retrospective cohort study of 169 patients who underwent spinal surgery with IONM at 2 institutions between 2013 and 2018. Signal changes detected were recorded as well as the surgeon's response to these changes. Neurological status was recorded using a standard neurological examination and characterized as per the McCormick Neurological Scale. Patients were followed up for 12 months after surgery. Results: A total of 169 spinal surgery cases with concurrent use of spinal cord monitoring were carried out in our institution between 2013 and 2018. The youngest patient was 14 years old, and the oldest was 92 years old (mean, 51.9 +/- 19.6 years). There were 100 female patients and 69 male patients. Most patients (n = 124) had no signal changes. Signal changes were observed in 26.6% of the cases (n = 45). Most of these signal changes were rectified through repositioning of the patient (n = 24). The other 21 patients saw no improvement in their signals before the end of their procedures; however, these 21 patients had no postoperative deficits (grade I). This brought the false positive rate to 38% (21/55); the false negative rate was 1.8% (3/169). Conclusion: This study showed similar outcomes in patients whether IONM signals were recovered or not. The false positive and false negative rates were high. Our study helps to raise awareness about IONM's strengths and weaknesses to inform future clinical practice. We recommend prioritizing clinical judgment in spinal surgery cases and using IONM with caution. Level of Evidence: 3.