Procedures and intervention
We used standard anesthesia management during TceMEP monitoring as described previously [Neuromuscular monitoring was achieved by ulnar nerve stimulation using a closed-loop muscle relaxant infusion system (CLMRIS-I, Guangxi VERYARK Technology Co., China.). All patients received a rocuronium infusion producing moderate blockade (at least two twitches in TOF) by the infusion system. The maintenance rate started from 0.6 µg/kg/min and was subsequently adjusted up to 12 µg/kg/min, and the bolus rate was 30 µg/kg/min. Rocuronium infusion was discontinued, and a bolus of sugammadex (2 mg/kg) was given while performing TceMEPs in the sugammadex group. The same volume of saline was administered to the control group while performing TceMEPs.