The Application Of Intraoperative Neurophysiological Monitoring During The Operation Of Intramedullary Spinal-cord Tumor Surgery

ObjectiveWe compared the postoperative short-term, long-term changes and differences of spinal neurological status between monitoring group and control group, and investigate the value and clinical significance of IONM for spinal cord protection in the intramedullary tumor surgery.MethodsThe monitoring group consisted of28patients operated from March,2009to July,2012, we monitored somatosensory evoked potentials, muscle motor evoked potentials and D-wave. The control group consisted of28patients, selected from among79patients who underwent intramedullary spinal cord tumor surgery from March,2000to February,2009, operated by the same team without IONM. Control patients were carefully matched to patients in the IONM group by preoperative neurological status. The McCormick grades variation were compared between the two groups during the pre-operation, discharge (mean12days after surgery) and follow-up(≥3months).ResultsAt discharge, the McCormick grade variation of the IONM group (mean,-0.29) was better than the control group (mean,-0.57); however, monitoring group compared with control group:P>0.05. There is no statistical significance in the difference. At the follow-up examination, the McCormick grade variation in the IONM group (mean,+0.29) was significantly better (p=0.008378) than that of the control group (mean,-0.25).Between discharge and the follow-up evaluation, the IONM group’s mean McCormick grade variation improved by0.58,whereas the control group’s mean grade improved by only0.22.Notably, only the INM group had an overall improvement in neurological status at follow-up (mean McCormick grade change,>0).Conclusion1. IONM can provide the instant feedbacks of the integrity of sensory and motor pathways. Avoiding to the irreversible damages, IONM could instruct operator to take corrective measures, revise the surgery progress in time, achieving the maximum resection of the tumor while preserving the function of spinal cord, to improve long-term motor outcome significantly.2. IONM has no significant effects to improve the short-term outcome of patients with intramedullary tumors because of transient motor deficits, which can be predicted by the intraoperative neurophysiological profile of patients.3. The benefit of IONM seems more evident for those patients who arrived at surgery in good neurological conditions compared with those with more severe deficits.