Intraoperative Neurophysiological Monitoring And Nerve Protection In Intraspinal Tumor Surgery

The incidence of intraspinal tumor account for about15%of central nervous system tumors. According to the tumor location in the spinal cord, intraspinal tumor can be classified into three main categories:intramedullary tumor, intraspinal extramedullary tumors and both. The main clinical features of Intraspinal tumor patients are pain, paresthesia, urination and defecation function disturbance, and so on. Meanwhile, the symptoms developed slowly, with the progress of the disease, made the quality of life of patients decline seriously and bring heavy burden to society and family. Surgery can be used as the first treatment way for the patients with intraspinal tumor, while it may cause iatrogenic spinal cord injury in surgery. In recent years, Intraoperative neurophysiological monitoring has been used widely in clinic and effectively reduces the intraoperative spinal cord injury, and plays an active role in protecting the spinal function, decreasing the operative complication and predicting prognosis. Intraoperative neurophysiological monitoring used in surgery includes motor evoked potentials (MEP), somatosensory evoked potential (SEP) and electromyography (EMG). Therefore, With respect to the application of the three Intraoperative neurophysiological monitoring technology in surgery, the present study explores the early warning criterion of MEP and SSEP, the early warning of SSEP incubation period for prognosis, and compares the influence on the prognostic of postoperative neural function when the intraoperative neurophysiological monitoring was used in surgery for intraspinal tumors or not. Part1Intraoperative monitoring and neuroprotective effects of MEP in surgery for intraspinal tumorsIn this part,31patients with amplitude changes of MEP in the surgery are divided into two groups based on amplitude change, those which amplitude change is less than50%or more than50%. The evaluation based on the change of postoperative symptoms and improvement of three-month follow-up symptoms showed no significant difference of symptom change between patients in the anesthesia recovered stage and three months follow-up stage, indicating that the operator should be reminded to notice the protection of the spinal cord function when amplitude of MEP is changing.Part2Intraoperative monitoring and neuroprotective effects of SSEP in surgery for intraspinal tumorsIn this part,41patients whose lower extremity SSEP changes in surgery are divided into two groups based on amplitude change, the standard line is amplitude change by50%.Through evaluation of improvement of patients’ postoperative symptoms, apparent paraesthesia would appear in the patients whose SSEP changes more than50%, otherwise, no apparent paraesthesia would appear in the patients whose SSEP changes less than50%and have no disproportionate impacts on prognosis. When compared with the general population, the incubation period for upper extremity SSEP in the patients whose upper extremity SSEP changes in surgery were prolonged before surgery, and did not change significantly after surgery. This reminds the operator to observe the amplitude changes of SSEP closely to protect the spinal cord function of the patients whose upper extremity SSEP changes in surgery were prolonged. Part3Intraoperative monitoring and neuroprotective effects of EMG in surgery for intraspinal tumorsIn this part,65patients were monitored by the free EMG, while20patients were monitored by induced EMG. The results showed that the free EMG could protect the nerves in real time, and the induced EMG could distinguish the tumor tissues and nervous tissues very well, which could further protect the nerve function. Part4The case series of clinical application and nerve function protection of the Intraoperative neurophysiological monitoring In this part,146patients are included and divided into two groups based on the monitoring situation:non-monitoring group and monitoring group. Compared with the non-monitoring group, the prognosis of the patients in monitoring group was clearly improving. For the intraspinal tumor located at cervical cord, the preoperative symptoms were mostly irreversible, by comparison, the postoperative symptoms in the monitoring group did not no longer aggravate sequentially. However, in the non-monitoring group, the postoperative symptoms did not get better or even become worse; For the intraspinal tumor located at thoracic cord, the prognosis of the patients in monitoring group was significantly better than the non-monitoring group; For the intraspinal tumor located at lumbosacral enlargement, conus and cauda region, the Intraoperative monitoring could play a very important role in the protection of spinal cord function.In general, the Intraoperative neurophysiological monitoring could effectively protect the neural function in surgery for intraspinal tumors, and the combined application of three monitoring technology (MEP, SEP and EMG) can significantly improve neurological outcome of surgery patients with intraspinal tumor.