Utility of Intraoperative Neurophysiologic Monitoring in Routine Anterior Cervical Spine Surgery

Abstract

Introduction: Intraoperative neurophysiologic monitoring (IOM) is commonly used in spine surgery; advantages include identification of intraoperative neurologic decline that may be related to a remediable cause. Disadvantages include increased time and cost, morbidity associated with the monitoring procedure, and the potential for false positive alerts prompting unnecessary action. The study’s goal was to assess whether use of IOM in routine, uncomplicated cases of anterior cervical discectomy and fusion (ACDF) surgery was of demonstrable benefit. Methods: 50 consecutive patients were identified who underwent one-level ACDF with anterior instrumentation for cervical disc herniation with radiculopathy without myelopathy. For all cases, a NIMS tube was used to monitor laryngeal nerve function, and EMG, SSEP, and MEP modalities were monitored. Hospital and postoperative records were investigated for the presence of IOM alerts, whether corrective action was taken during surgery, and the presence of any postoperative neurologic deficits. Results: In all cases, there were no alerts of laryngeal nerve dysfunction, or SSEP/ MEP abnormality. In 12 cases, transient EMG irritation activity was documented; in no cases was there any change to the surgical procedure, such as abandonment of surgery, removal of implant, etc. There were no instances of new or worsened postoperative neurologic deficit, and clinical findings of vocal cord dysfunction. Conclusion: In ACDF with anterior instrumentation for cervical disc herniation with radiculopathy without myelopathy, IOM use did not convey any identifiable advantage. Therefore, the data does not support considering IOM to be required or standard of care for routine, uncomplicated ACDF surgery.