The Protection And Prognosis Of Facial Nerve In Large Acoustic Neuroma Surgery

【Object】With the modern development of Neurosurgery microscopy and the use of intraoperative neurophysiological monitoring, facial nerve function significantly improved in cerebellopontine angle tumors, particularly acoustic neuroma surgery. Therefore the probability of injury significantly decreased.Neurophysiological monitoring technique in surgery to monitor the integrity of the nervous system has been for many years.In order to further improve the acoustic neuroma surgery, especially for large acoustic neuroma surgery safety and reduce the incidence of intraoperative facial nerve paralysis, it is necessary to monitor facial nerve in the operation. In large acoustic neuroma microsurgery we combine EMG and brainstem auditory evoked potentials, somatosensory evoked potentials, transcranial electrical stimulation motor evoked potentials and so on to study their function in facial nerve protection during surgery.【Material and Method】At Second Xiangya Hospital Neurosurgery of Central South University, we use intraoperative electrophysiological monitoring for 67 patients with large acoustic neuroma. All patients were diagnosed as acoustic neuroma.We remove the tumor by the sigmoid sinus Microsurgical posterior approach during facial nerve were monitored including 16 cases removed with endoscopic-assisted,33 cases monitored by simple intraoperative electromyography (EMG).Besides,34 cases were monitored by intraoperative electromyography (EMG), brain stem auditory evoked potentials (BAEPs), somatosensory evoked potentials (SSEPs), transcranial electrical stimulation motor evoked potential (TES-MEPs). After operation we evaluate the motor and sensory function in hospital. At facial nerve function, all patients were investigated for long time, by this, we explore the related factors. We combine the results of intraoperative monitoring and facial nerve function,somatosensory, together for prospective observational study. Analyze the feasibility, safety, sensitivity, specificity and impact on the surgical procedure of joint monitoring.The preoperative and postoperative facial nerve function is judged by House-Brackmann grading standards. We evaluate facial nerve function after 1 week, 3 months, 6 months and later. All data are analyzed by statistical software.【Results】Of 67 patients with large acoustic neuroma, the number of tumor total removed is 64 cases (95.5%), subtotal is 3 cases (4.5%), no deaths. In surgery, 63 patients' (94,0%) facial nerve dissection are retained. After 6 months of surgery, the facial nerve function is:H-BⅠ42 cases, H-BⅡ15 cases, H-BⅢ5 cases, H-BⅣ3 cases, H-BⅤ2 cases, H-BⅥ0 cases. The excellent rate (H-BI-Ⅱlevel) is 85.1%. [Conclusion]1) Neurophysiological monitoring in acoustic neuroma surgery plays an important role in protection and prognosis of facial nerve function.2) The simple detection of EMG monitoring and joint monitoring in the protection of facial nerve function has no significant difference (P> 0.05).3) The texture of acoustic neuroma has no correlation with the recovery of facial nerve function after surgery.4) The excellent rate of Cystic acoustic neuroma is much lower than the actual acoustic neuroma after a week of surgery.5) Joint detection is not noly protect the facial nerve,but also protect the cranial nerve and brainstem function.6) The micro-manipulation techniques and experience of surgeon play an important role in the surgery.7) Endoscopy can be better remove the tumor within the auditory canal and reduce the incidence of cerebrospinal fluid otorrhea.8) The effective joint monitoring of SEP+MEP+EMG+BAEP in the surgery can be possible to avoid "false negative or false positive" results, and protect nerve, brain stem function greatestly to improve the patients quality of life.