Analysis Of Surgical Efficacy And Factors Influencing Postoperative And Auditory Nerve Function In The Resection Of Vestibular Nerve Sheath Tumors Via A Posterior Approach To The Sigmoid Sinus

Objective: To explore the surgical strategy of resection of vestibular schwannoma via retrosigmoid sinus approach and analyze the postoperative complications;especially focused on the early and long-term factors affecting facial and auditory nerve function.Methods: From January 1,2017 to January 31,2022,220 patients with vestibular schwannoma confirmed by postoperative pathological examination in the same treatment group of Neurosurgery Department of the First Affiliated Hospital of Kunming Medical University were selected as the study subjects,and the data of the patients were collected,including general demographic characteristics,preoperative symptoms,tumor side,tumor diameter,presence or absence of peritumoral edema,tumor texture,The degree of tumor resection and postoperative use of nimodipine were analyzed.According to the outcome of postoperative facial and acoustic nerve function,the patients were divided into good facial nerve function(HB I-II)and poor facial nerve function(HB III-VI),with practical hearing(AAO-NHS A and B)and without practical hearing(AAO-NHS C and D).The outcome was used as the dependent variable to construct a multivariate logistic regression model to analyze the relationship between the above factors and the facial and acoustic nerve function at 7 days,3 months and 1year after surgery.Results:1.In 220 cases of vestibular schwannomas,161 cases(73.2%)were totally resected,59cases(26.8%)were partially resected,208 cases(93.2%)were anatomically preserved facial nerve,174 cases(79.1%)were anatomically preserved cochlear nerve.Postoperative complications included loss of practical hearing in 88 patients(40%),facial nerve dysfunction in 58 patients(26.4%),postoperative hematoma in 9 patients(4.1%),cerebrospinal fluid leakage in 13 patients(5.9%),infection in 11 patients(5%),posterior cranial nerve dysfunction in 20 patients(9.1%),poor wound healing in 12patients(5.5%),and gait instability in 19 patients(8.6%).2.118 patients(53.6%)had good facial nerve function at 7 days,165 patients(75%)at3 months and 206 patients(93.6%)at 1 year after operation.87 cases(39.5%)retained hearing 7 days after operation,83 cases(37.7%)retained hearing 3 months after operation,and 54 cases(24.5%)retained hearing 1 year after operation.3.Multivariate logistic regression analysis showed that tumor diameter,adhesion degree between tumor and facial nerve and preoperative facial nerve function were independent factors affecting facial nerve function in the early postoperative period.Tumor diameter(≥ 4cm)was a risk factor for long-term facial nerve function.Correlation analysis showed that the early postoperative facial nerve function was positively correlated with the long-term facial nerve function(P<0.001).4.The early postoperative hearing function was positively correlated with the long-term postoperative hearing function(P <0.001).Multivariate analysis showed that tumor diameter,practical hearing and duration of nimodipine were the influencing factors of early hearing outcome.Tumor diameter and preoperative hearing are important predictors of long-term hearing function after operation.Conclusions:1.The retrosigmoid approach is one of the most commonly used microsurgical procedures for vestibular schwannomas.Combined with intraoperative electrophysiological monitoring,it is safe and effective for most vestibular schwannomas.2.The diameter of tumor,the degree of adhesion between tumor and facial nerve and the function of facial nerve before operation were the independent factors affecting the function of facial nerve in the early postoperative period.Tumor diameter is an important predictor of long-term preservation of facial nerve function.The intraoperative facial nerve anatomy preservation is the decisive factor for the postoperative facial nerve function preservation of vestibular schwannoma patients.Patients with intact facial nerve anatomy preserved during surgery have a higher probability of recovering to good facial nerve function one year after surgery.3.Tumor diameter and preoperative hearing function are not only independent factors of early postoperative hearing function,but also important predictors of long-term postoperative hearing function.Patients who preserve cochlear nerve anatomy during surgery and retain functional hearing early after surgery may still lose functional hearing during follow-up.4.Nimodipine has potential neuroprotective effect in addition to vascular protection.It can effectively improve the early practical hearing retention rate after operation in patients with vestibular schwannoma after a full course of treatment,but has no significant effect on long-term hearing function.