Efficacy of multimodal intraoperative neurophysiology monitoring to distinguish the nervous system injury during surgery for chronic cervical compressive myelopathy

Abstract

Objective To study the efficacy of intraoperative neuromonitoring with SEP, MEP and EMG to predict of spinal cord and nerve root injury during surgery for chronic cervical compressive myelopathy. Methods From October 2014 to June 2016, 107 patients (80 males, 27 females) who underwent surgery for chronic cervical compressive myelopathy and intra-operative neuromonitoring with SEP, MEP and EMG were enrolled in this study. The mean age was 53.36±11.35 years (24-79 years), and the mean follow-up time was 7.94±6.05 months (1-18 months). The monitoring method, abnormal alarm, treatment and outcome of intraoperative SEP, MEP and EMG were recorded in all patients. The preoperative, postoperative and last follow-up neurologic functions were compared. True positive, false positive, true negative and false negative cases were collected in all patients. Sensitivity, specificity, positive predictive value and negative predictive value were calculated, and the utility of monitor spinal cord and nerve root injury was analyzed. Results SEP, MEP and EMG baseline values of 107 patients were established at the end of exposure. A total of 8 patients with intraoperative neurophysiology monitoring were abnormal (4 cases of anterior surgery, 4 cases of posterior surgery), including 1 case with abnormal SEP and MEP, but EMG was normal, he became incomplete paralysis postoperatively; 4 cases with abnormal MEP and EMG, but SEP was normal, they suffered C5 nerve root palsy postoperatively; 2 cases with abnormal MEP, while SEP and EMG were normal, one was C5 nerve root palsy and another was incomplete paralysis for the right side of the limb postoperatively; 1 case with abnormal EMG, but SEP and MEP were normal, he was C5 nerve root palsy postoperatively. 1 patient with anterior surgery was false negative of intraoperative neurophysiology monitoring, it was not found abnormal during surgery, but the patient was C5 nerve root palsy after operation. The utility of monitor spinal cord injury, the sensitivity and specificity of SEP was 50% and 100%, respectively. The positive predictive value was 100% and the negative predictive value was 99.06%. The sensitivity and specificity of MEP were 100%, positive predictive value and negative predictive value were 100%. The effect of monitor nerve root injury, the sensitivity and specificity of SEP was 0 and 100%, respectively. The positive predictive value was 0 and the negative predictive value was 93.46%. The sensitivity and specificity of MEP was 71.43% and 100%, respectively. The positive predictive value was 100% and the negative predictive value was 98.04%. The sensitivity and specificity of EMG sensitivity was 71.43% and 100%, respectively. The positive predictive value was 100% and the negative predictive value was 98.04%. Conclusion During operation of chronic cervical compressive myelopathy, SEP and MEP for spinal cord injury monitoring, and MEP and EMG for nerve root injury monitoring were effective ways to promise comprehensive monitor the spinal cord and nerve root system. Key words: Cervical vertebrae; Spinal cord compression; Evoked potentials, somatosensory; Evoked potentials, motor; Electromyography