The Application Of Neurophysiological Monitoring During The Operation Of Acoustic Neuroma

Objective: by continuous monitoring Hemifacial EMG, to discuss the value of facial nerve retaining in acoustic neuroma surgery which apply the facial nerve neurophysiological monitoringMethod: 40 patients, ASA I^II, 17⁷0 years old, are scheduled for the operations of acoustic neuroma. The patients are randomly divided into monitoring group and non-monitoring group. Each of them has 20 cases.Preoperative tests and chemical examination are normal. After entering operating room, monitoring of ECG,HR,SpO₂,BP are carried out on the patients, Patients with oxygen mask breathing (4L/min) were performed induced general anesthesia by intravenous injection with midazolam 0.02-0.04mg·kg^-1,fentanyl 2³ ug·kg^-1,atracurium 0.15 mg·kg^-1 and etomidate 0.3 mg·kg^-1 in turn. Tracheal intubation is followed by mechanical ventilation. Prime setting: breathing rate (f)= 12times·min-1 , VT=8-10 mL·kg^-1 , fresh gas flow=2.0 L·min-1. Adjusting f and VT according to SpO₂ and partial pressure of carbon dioxide in endexpiratory gas(PET CO₂ ),to maintain SpO₂ 98%～100%,PET CO₂ 30-40 mmHg. Maintenance of anesthesia is that propofol(6-9mg / kg / h)and remifentanil (10-15μg /kg/h) was administrated by target-controlled infusion (TCI) during the operations into vein, atracurium is used only once in anesthesia induction and should not be administrated in the operating progress.20 patients in monitoring group who are used nerve monitoring in the operation; 20patients in non-monitoring group who are not used nerve monitoring in the operation. By monitoring EMG to monitor the function of Facial nerve and trigeminal nerve, used epoch XP which was produced by AXON company of America. After general anesthesia, put the recording needle probe in the ipsilateral orbicularis muscle, orbicularis oris and masseter. Polar spines in the ipsilateral shoulder skin, positive and negative probes apart 1cm, with a cut of the film fixed probe. All the surgeries were completed by one surgeon. Surgical procedures are used suboccipital retrosigmoid approach. Nerve stimulation waveform monitor shows the amplitude and shape whenTraction, compression, heating and so on are occurred in the operation, then we can according to the changes in facial muscle EMG to change the surgical method. The purpose is to protect the facial nerve and trigeminal nerve. Statistical treatment is completed with SPSS13.0 package. Measurement data is expressed by mean(X)±standard deviation(s), Count data usingχ2 test, P<0.05 is considered as statistical significance.Result:1. The anatomical retention of facial nerve: monitoring group 19 (95%), non-monitoring group 16 (80%). Monitoring group compared with non-monitoring group: P>0.05. there is no statistical significance in the difference. But Monitoring group is higher than non-monitoring group.2.1 year after operation, retention rate of facial nerve function of Monitoring group compared with non-monitoring group: P < 0.05, statistical significance.3.Two groups were compared within groups: functional retention rate of facial nerve of 1year compared with 1 week after operation: P<0.05, statistical significance.Conclusion:1. Facial nerve neurophysiological monitoring has no obvious effect on anatomical retention rate of facial nerve after the operation of acoustic neuroma. 2. Facial nerve neurophysiological monitoring can improve the functional retention rate of facial nerve after the operation of acoustic neuroma.3. Functional retention rate of facial nerve of 1year is obvious higher than 1 week after operation...