听神经瘤内听道口磨开和肿瘤切除技术探讨

Microsurgical technique for internal auditory canal drilling and acoustic neuroma removal

目的探讨听神经瘤内听道的显微外科处理,提高肿瘤的全切除率和面神经的功能保留率。方法回顾性分析经枕下乙状窦后内听道入路行显微外科手术治疗听神经瘤的32例患者的临床资料,术前均行后颅窝岩骨CT薄层扫描,术中采用磨钻(美敦力公司)或磨骨刀(SONOPET公司)将内听道磨开,磨除时后壁尽量磨开,术中均行面神经功能电生理监测,对内听道内肿瘤处理的手术技巧进行分析。结果听神经瘤全切除30例,全切除率为96%;次全切除2例,占4%。面神经解剖保留32例,面神经解剖保留率达100%,其中H.B分级Ⅰ级8例,H.B分级Ⅱ～Ⅲ级24例;功能良好以上保留率为100%。面神经位于前下位置16例,居中6例,前上10例。内听道处理时术中颈静脉球高位4例,磨除内听道时轮廓化4例,出血2例。无术后死亡患者。结论熟练掌握内听道解剖和显微磨钻技术,充分打开内听道后壁,结合术中电生理监测和显微外科技术,可提高听神经瘤的全切除率和面神经功能保留级别。

Objective To explore the microsurgical technique for internal auditory canal drilling and acoustic neuroma removal,so as to improve the total tumor removal rate and the preservation rate of facial nerve function.Methods The clinical data of 32 patients with acoustic neuroma removed microsurgically through subocciptal transmeatal approach were retrospectively analyzed.CT scan of the petrous bone was done with thin slice before operation and after the wall of internal acoustic meatus was drilled away.Medtronic drill apparatus or sonopet untrasonic apparatus was adopted;electrical-neurophysiological monitoring was applied for preserving the facial nerve function during operation.The surgical techniques for inside and near internal acoustic meatus were analyzed.Results Tumors were totally removed in 30（96%）patients and subtotally removed in 2（4%）.The facial nerves were anatomically preserved in all the 32 patients.According to House-Brackman Facial Palsy Grade System,the facial function reservation was as following：Grade 1 in 8 cases,Grade 2-3 in 24 cases.There were 16 cases with the facial nerve locating at the anterior-inferior of inner meatus,6 cases at the anterior-middle position,and 10 cases at the anterior-superior.During operation,4 cases had the Jugular bulb at high position,4 cases were skelectonized and 2 cases had hemorrhage during drilling.There was one death postoperatively.Conclusions Good command of the techniques of microdrill,full opening of the posterior wall of acoustic meatus,and assistance with electrical-physiological monitoring can improve the total removal rate of tumors and enhance the preservation rate of facial function.