A Study On Application Of Intraoperative Neurophysiological Monitoring In Oncosurgery

Objective Intraoperative neurophysiological monitoring (IONM) applies multiple electrophysiological techniques to provide continuous information about electro-physiological signal changes during surgery. The main purposes of our study are to apply the electrophysiological techniques to monitor the nervous system during oncosurgery, and to present the schemes and investigate applied value.Methods Between December2010and April2012,65patients with tumors were operated on in the department of neurosurgery, orthopedics, head&neck and gynecology. BAEPs, SEPs, MEPs and free-running&trigger EMG were applied to achieve on-line monitoring of the brainstem, sensorimotor cortex, spinal cord and peripheral nerve. Parameters and neurological outcomes were recorded and then analyzed.Results Twenty-eight patients with posterior fossa tumor and4patients with cervical cord tumor had intraoperative BAEPs to monitor the brainstem. Among them,13patients also had SEPs and TcMEPs monitoring. It was found that there was no significant change in the waveform. Thirty-two patients undergoing surgery on skull base or head&neck tumor had continuous records of facial nerve EMG. Spikes and bursts lasting up to several minutes were observed in9patients. The facial nerve was functionally preserved in30patients. Ten patients with tumors around the central cortical region had phase reversal and Functional Brain Mapping (FBM). The position of the central sulcus and sensorimotor cortex were all confirmed. Thirteen patients had SEPs and TcMEPs monitoring in spinal column or spinal cord surgery. Six of them presented with significant changes in amplitude or latency of SEPs, while5patients had marked reduction in amplitude of MEPs. Six patients had Intraoperative Electrical Stimulation (IES) of Pelvic Autonomic Nerves (PAN) during Systematic Nerve-Sparing Radical Hysterectomy (SNSRH). The CMAPs or CNAPs were evoked. Radical resection was achieved in59patients (90.77%) while subtotal resection was achieved in6patients (9.23%). The Karnofsky Performance Status (KPS) scale was evaluated at the time of discharge. Forty-three patients (66.15%) were higher than80; nineteen patients (29.23%) achieved70; and2patients (3.08%) achieved50.Conclusion BAEPs, SEPs, TcMEPs can be used on monitoring brainstem and upper cervical cord, while the latter two can also be applied to observe the functionality of spine cord. Peripheral nerves can be monitored by free-running&trigger EMG. The position of the central sulcus and sensorimotor cortex can be confirmed using phase reversal and Functional Brain Mapping. IONM can lower the morbidity rate and achieve radical resection during oncosurgery. However, the follow-up is needed for the late outcomes and recovery of neurological outcomes.