Evaluation of Reliability of Post-Tetanic Motor-Evoked Potential Monitoring During Spinal Surgery Under General Anesthesia

Abstract

The results indicate that p-MEP is a more reliable method to detect changes in motor function during spinal surgery under general anesthesia in comparison with c-MEP.

Evaluation of the applicability of sevoflurane during post-tetanic myogenic motor evoked potential monitoring in patients undergoing spinal surgery

“…Recently, we developed a new technique to improve the reliability of MEP recording, called post-tetanic MEP (p-MEP), in which the MEP amplitude, compared with that of conventional MEP (c-MEP), can be enlarged by tetanic stimulation of peripheral nerves prior to transcranial electrical stimulation [14][15][16][17]. Our previous data suggested that tetanic stimulation (50 Hz, 50 mA) of peripheral nerve with a duration of 3-5 s and a posttetanic interval of 1-5 s could be applied for the purpose of augmenting the MEP amplitude [14].…”

Recent advances in the monitoring of myogenic motor-evoked potentials: development of post-tetanic motor-evoked potentials

“…In fact, falsepositive results of intraoperative MEPs have been reported repeatedly, at a range of 0% to 27%, because of the suppressive effects exerted by a variety of factors, including anesthetic agents, neuromuscular blocking agents, hemodynamic changes, temperature, and failure of electrodes [15,16]. In our series of 80 patients undergoing spine and spinal cord surgery, the false-positive rate of MEP monitoring was 4% when c-MEP was used for monitoring; however, when p-MEP was used for monitoring, the false-positive rate was 0% [14]. This study also showed that there were no false-negative results of c-MEP and p-MEP.…”

“…Recent reports have indicated that the success rates of baseline MEP recording during spinal surgery were 89%-100% and 30%-50% in patients without and with preoperative motor weakness, respectively [12,13]. In our recent study, the success rates of baseline MEP recording were signifi cantly improved by using p-MEP in patients without and with preoperative motor weakness (c-MEP, 74.5% and 51.7%, respectively; p-MEP, 96.1% and 86.2%, respectively) [14].…”

Evaluation of Combined Use of Transcranial and Direct Cortical Motor Evoked Potential Monitoring During Unruptured Aneurysm Surgery

“…Generally the stimulus intensity of transcranial stimulation in spine and aortic surgery is determined at the beginning of MEP recording and is set just supramaximal to each stimulus (approximately 500 V). 1) In this study, the intensity of stimulus was 210 ± 37.6 V (range 140-250 V). Initially we identified the threshold level, at which the MEP waveform was elicited from only the contralateral APB.…”

“…In contrast, transcranial MEP can be performed without insertion of grid electrodes on the brain surface and throughout the course of surgery, and is therefore widely used not only in brain surgery but also in spine and aortic surgery. 1,5) Direct recording of MEPs from the spinal cord (D waves) after transcranial stimulation demonstrated that high-intensity stimulation can activate the corticospinal tract as deep as the pyramidal decussation. 3) To compensate for the weaknesses of direct MEP, we have used transcranial electrical stimulation combined with direct cortical stimulation to elicit MEPs for intraoperative monitoring.…”