A study on the usefulness of motor evoked potentials monitoring during spinal surgery

ABSTRACT

BACKGROUND: Intraoperative monitoring of transcranial electrical motor evoked potentials (TCE-MEPs) can be a useful tool to detect iatrogenic spinal cord injury. But the efficacy of TCE-MEPs monitoring in the spine surgery has not been reported in South Korea. The purpose of this study is to investigate the reliability of intraoperative TCE-MEPs in spinal surgery. METHODS: Thirty five patients scheduled for elective surgery for spine correction were enrolled in the study. After induction of general anesthesia with target controlled infusion (TCI) system of propofol and remifentanil, intraoperative TCE-MEPs from upper or lower limb muscles were monitored. No additional muscle relaxants were given except for tracheal intubation. We recorded intraoperative abnormal signs of TCE-MEPs and postoperative neurologic deficits. From these results, sensitivity, specificity, positive predictive value, and negative predictive value of TCE-MEPs monitoring for the detection of neurologic damage during spinal surgery were calculated. RESULTS: Six patients showed decreases in amplitudes. Postoperative neurologic deficits occurred in 5 patients out of them. Only one patient developed postoperative neurologic deficit even though there were no intraoperative TCE-MEPs change. Sensitivity, specificity, positive predictive value, and negative predictive value of TCE-MEPs monitoring for the detection of neurologic deficits were 83.3%, 96.7%, 83.3%, 96.7%, odds ratio was 140 and relative risk was 24.2. CONCLUSIONS: Intraoperative TCE-MEPs monitoring is a reliable and sensitive method to detect the neurologic deficits during spinal surgery.