Abstract:

Objective　To investigate the efficacy of combined monitoring of motor evoked potentials withtrans-cranial electrical stimulation (TES-MEP), somatosensory evoked potentials(SEP), free and tirgger EMG for surgical treatment forintraspinal occupancy surgery occupying lesion.    Method    Combined SEP, TES-MEP, free and trigger EMG monitoring were employed in forty-two cases of surgical treatment forintraspinal occupancy surgery occupying lesion,  including one cervicalcase, fourteen thoracic cases, thirteen thoracolumbar cases, eleven lumbar cases, and three sacral cases. SEP and TES-MEP were used to monitor the precise status of sensory and motor pathways in spinal cord. Free and trigger EMG responses were used to more accurately explore and distinguish distribution of nerve tissues in and around theintraspinal occupancy.All cases were performed after surgery.    Results    ①SEPwas successfully achieved in 47(100%)cases. TES-MEP was successfully achieved in 44(93.6%)cases. Combined motor and sensorymonitoring was successfully achieved in 44(93.6%)cases. The abnormality of SEP was observedin 10 cases(19.1%), while the abnormality of MEP was observed in eight cases(17.0%). False negative and positiverate were 0% with combined SEP and TES-MEP monitoring. 10 positive cases of evoked potential were all caused by operations. Eight of them recovered gradually after the alarm in time to take measures. The other two cases who were only positive in TES-MEP failed to recover and postoperative muscle strength decreased. The symptoms were alleviated in six cases with SEP waveforms getting better. ②34 cases of EMG?response was observed. Postoperative urination dysfunction occurred in one case in which the intraspinal lesion was wrapped by tight cauda equina. However, this patient recovered in the twelfth day after operation.   Conclusions    ①During surgical treatment for intraspinal occupancy surgery occupying lesion,combined application of  SEP and TES-MEP can reflect the physiological and pathological conditions of spinal cord after ruling out the interfering factors, and improve the monitoring effect . ②Intraoperative monitoring of free and trigger EMG can not only accuratelyexplore and distinguish distribution of nerve tissues in and around the intraspinal occupancy, but also respond to the nerve irritation timely, and prevent iatrogenic nerve injuries.

Key words: Somatosensory evoked potential；　Motor evoked potentials；　Electromyography; , Intraoperative monitoring;　Spinal cord diseases