Relative Factor Analysis Of Facial Nerve Functional Injury After Acoustic Neuroma Resection

Objective:Postoperative facial nerve injury symptoms,such as peripheral facial paralysis,could also occur in acoustic neuroma patients whose facial nerves were remained intact during operations.This study was aimed to evaluate influence factors of postoperative facial nerve function,which could provide theoretical support for protection of facial nerve function and improvement of prognosis.Methods:73 patients with acoustic neuroma who were operated between January 1st 2014 and December 31st 2014 in the second affiliated hospital of Zhejiang University,School of medicine and met our criterion were analyzed retrospectively.House-Brackmann facial nerve function classification system was used to evaluate the postoperative facial nerve function of patients.Variables analyzed included sex,age,the tumor size,the intra-operative facial nerve monitor,the extent of tumor excision and the operation time.Univariate chi-square analyses and Logistic regression were performed to detect relative influence factors.Results:In total,73 acoustic neuroma patients were included.27 were male and 46 were female,and the ratio of male to female was 1:1.7.The ages of patients ranged from 24 to 76 years old of which the mean was 50 years old.The tumors' diameters ranged from 1.2cm to 6.3cm of which the mean was 3.1cm.There were 33 cases with tumors' diameters larger than 3cm,while others' were less than 3cm.53 cases underwent intra-operative facial nerve monitoring and 20 cases did not.51 cases achieved total tumor resection and 22 cases didn't.The operation time of 42 cases were less than 4 hours and 31 cases were equal to or more than 4 hours.52 cases(71.2%)achieved better postoperative neurological outcome(H-B Grade ?-? and 21 patients gained poor postoperative outcome(H-B Grade ?-?).Univariate analyses showed that the tumor size(?2 = 11.427,P = 0.001),intra-operative facial nerve monitor(?2 =6.061,P = 0.014),extent of tumor excision(?2 = 6.928,P = 0.008)and operation time(?2 = 4.560,P = 0.033)were associated with postoperative facial nerve function.Further logistic regression demonstrated that the tumor size and intra-operative facial nerve monitor were independently related with postoperative facial nerve injury.Conclusion:The tumor size and intra-operative facial nerve monitor were independently related with postoperative facial nerve function.The larger the tumor was,the worse the facial nerve function became.The conduction of intra-operative facial nerve monitor was benefit to the protection of facial nerve function.