Comparison of the Effects of Vecuronium and Cisatracurium on Electrophysiologic Monitoring During Neurosurgery

Recently intraoperative motor evoked potential monitoring (MEP) is widely used to reduce neural damage during neurosurgery. As neuromuscular blockade(NMB) during MEP monitoring decreases the amplitude of MEP, partial NMB is usually maintained during general anesthesia. Continuous infusion of NMB agent is preferred than bolus infusion during MEP monitoring. There are a lot of NMB agents in clinical use. But there have been no reports about the effect of changing NMB agent on efficacy of MEP monitoring. Therefore, the investigators performed a randomized controlled trial to evaluate the effect of changing NMB agent on the variability of MEP amplitude during neurosurgery.