Value of intraoperative neurophysiological monitoring to reduce neurological complications in patients undergoing anterior cervical spine procedures for cervical spondylotic myelopathy

The primary aim of this study was to conduct a systematic review of reports of patients with cervical spondylotic myelopathy and to assess the value of intraoperative monitoring (IOM), including somatosensory evoked potentials, transcranial motor evoked potentials and electromyography, in anterior cervical procedures. A search was conducted to collect a small database of relevant papers using key words describing disorders and procedures of interest. The database was then shortlisted using selection criteria and data was extracted to identify complications as a result of anterior cervical procedures for cervical spondylotic myelopathy and outcome analysis on a continuous scale. In the 22 studies that matched the screening criteria, only two involved the use of IOM. The average sample size was 173 patients. In procedures done without IOM a mean change in Japanese Orthopaedic Association score of 3.94 points and Nurick score by 1.20 points (both less severe post-operatively) was observed. Within our sub-group analysis, worsening myelopathy and/or quadriplegia was seen in 2.71% of patients for studies without IOM and 0.91% of patients for studies with IOM. Variations persist in the existing literature in the evaluation of complications associated with anterior cervical spinal procedures. Based on the review of published studies, sufficient evidence does not exist to make recommendations regarding the use of different IOM modalities to reduce neurological complications during anterior cervical procedures. However, future studies with objective measures of neurological deficits using a specific IOM modality may establish it as an effective and reliable indicator of injury during such surgeries.