听神经瘤手术内听道处理及面听神经保护

Management of internal acoustic meatus and facial nerve preservation in operations of acoustic neuromas

目的探讨听神经瘤手术内听道内肿瘤的处理方法，并对显微解剖保留面神经的手术经验和技巧进行讨论，以提高肿瘤的全切率和面神经的保留率。方法回顾性分析经枕下乙状窦后-内听道入路显微外科手术治疗的听神经瘤49例，术前行CT内耳道薄层扫描，术中行面神经功能和脑干听觉诱发电位监测。对听神经瘤内听道处理的手术技巧进行分析。结果术中面神经解剖保留43例，面神经解剖保留率为87．8％，出院时功能保留35例（H—B分级，Ⅰ～Ⅱ级）。解剖未能保留6例，其中2例行面神经端．端吻合。肿瘤全切45例，全切除率为91．8％；近全切除4例。术后无死亡病例。结论熟悉内听道内面听神经与肿瘤的病理解剖关系。熟练掌握显微手术技巧并结合术中监测，对肿瘤全切除和面听神经功能保护具有重要的意义。

Objective To explore the micresurgical removal techniques of acoustic neurow, as in internal acoustic meatus, to discuss the skills and experiences of nerve preservation, and to improve the rate of tumor removal and facial nerve preservation, Methods A total of 49 patients suffering from acoustic neurow, as treated micresurgicaUy with suboccipital retrosigmoid transmeatus approach from January 1998 to December 2004 were analyzed retrospectively. CT scan of internal auditory canal was perfomed preoperatively, and facial nerve function monitoring and brain stem evoked potential were also performed intraoperafively. The micresurgical skills were also analyzed retrospectively. Results Anatomic preservation of facial nerve was achieved in 43 cases with preservation rate of 87.8%, and functional preservation of facial nerve （H-B grading, Grade Ⅰ and Grade Ⅱ） was in 35 patients at discharge. Anatomic preservation of facial nerve was failed in 6 cases, thereinto, intracranial end to end anastomosis of the facial nerve was perfomed in 2 cases. Total resection of the tumor was achieved micresurgically in 45 cases with a total removal rate of 91.8% and subtotal resection in 4 cases. No patient died. Conclusion h is very inportant of learning the pathological anatomic relationships among acoustic nerve, facial nerve and the tumor in internal acoustic canal and mastering micresurgical technique of totally resecting tumor and preserving the facial nerve.