Outcome After Microsurgical Resection Of Large And Extra-large Vestibular Schwannoma With Intraoperative Monitoring And Analysis Of Correlation Factor

ObjectivesTo retrospectively study the outcomes of236cases vestibular schwannoma after microsurgical resection with intraoperative monitoring, analyse correlation factor and find ways of preventing nerver function and improving life quality.MethodsBetween January2002and December2010,236patients who had undergone VS resection by professor Yuan Xianrui at the neurosurgical department of Xiangya hospital were included in this retropestive study.All of the medical records and follow-up data are analyzed. House-Brackmann Scale was used to evaluate facial nerve function.PTA and SDS were used to appraise hearing function,and the appraisal results were calssified with American Academy of Otolaryngology-Head and Neck Surgery criteria.The life quality after operation was evaluated with Karnofsky performance status scale.The study data were put into ststistic analyse to identify the factors affecting postoperation results.ResultsTumor size ranged from30to65mm,with a mean of42.9mm.All of the tumors were operated on using the suboccipitolateral approach. Of the236cases,complete tumor removal was achieved in225cases(95.3%),near-total resection in9cases, partial resection in1case, subtotal in1case.3cases died after operation.The facial nerve was completely preserved in96.6%of cases.198patients were followed up at least1year.Overall,82.3%of them had normal or near normal facial nerve function(H-B grade Ⅰ or Ⅱ) post-surgically,and13.1%had accectable facial nerve function(H-B grade Ⅲ).Post-operative facial function was intimately correlated with tumor size and symptom lasting time through statistical evaluation,and had no relationship with other factors.116patients had follow-up data of hearing.85cases had hearing function preopera-tively,and59cases of them had hearing preservation.10(16.94%) cases maintained useful hearing postoperatively(AAO-HNS A and B).The hearing function of24(20.69%) patients even improved after operation.There were90.26%(213cases)of all236patiernts with excellent grade on KPS(KPS≥80%) after operation.Conclusions1.Complete resection of large and extra-large vestibular schwannoma with preservation of cranial nerve function is the most important aim of microsurgery,and it maybe obtained via sboccipital retrosigmoid approach.2. Facial nerve can be anatomically preserved in most cases of large and extra-large vestibular schwannoma.If facial nerve can be preserved,the nerve function can regain to excellent grade gradually after1year3.It is difficult to preserve hearing function with resection of large and extra-large vestibular schwannoma,but not impossible.No matter what size of tumor is and which level of hearing the patients have,the effort to preserve the cochlear nerve in operation should not be given up.4.Many factor may influent the outcome of postoperative facial nerve function.In our study,the tumor size and experience of operator are the most important factors.Other factors,such as age,course of symptom and texture of tumor et al,can not affect facial nerve function as single factor.