大型听神经瘤显微切除术中应用IFNM技术可视化面神经

目的探讨术中面神经监测(IFNM)技术在显微切除大型听神经瘤过程中保留面神经的效果。方法对86例单侧大型听神经瘤(直径≥3cm)病人采用枕下乙状窦后入路显微切除肿瘤。切开肿瘤背侧包膜前,根据电刺激肿瘤表面及边缘产生的激发性肌电图来探查并确认面神经的行走路径;术中采用自发性肌电图监测面神经,使其免受牵拉、挤压或损伤,交替采用激发性肌电图实时探查、确认面神经,从而在虚拟状态下达到面神经"可视化"。结果本组肿瘤全切除79例,占91.9%;次全切除5例,占5.8%;大部分切除2例,占2.3%。面神经解剖保留74例,保留率达86.0%;实用听力保留28例,占32.6%。术后面神经功能House-Brackman分级:Ⅰ～Ⅱ级64例,占74.4%;Ⅲ～Ⅳ级15例,占17.4%;Ⅴ～Ⅵ级7例,占8.2%。结论采用IFNM技术术中"可视化"面神经是大型听神经瘤切除术后面神经得以保留的关键,而娴熟的显微手术技巧、扎实的桥小脑角局部解剖知识是手术成功的保障。

Application of intraoperative facial nerve monitoring during microsurgical resection of large acoustic neuromas

Objective To explore the protective effects of intraoperative facial nerve monitoring （IFNM） on the facial nerve in microsurgical treatment of large acoustic neuromas. Methods Eighty six patients with large acoustic neuromas （≥3 cm） underwent surgical treatment via suboccipical retrosigmoid transmeatal approach. The course of the facial nerve was explored and established according to electromyogram evoked by stimulating the tumor surface and tumor edge before sectioning the dorsal capsule. During the operation, spontaneous electromyography was performed alternatively to monitor the facial nerve for avoiding drawing and extrusion, and evoked electromyography was used to identify the facial nerve, so that ＂visualizing the facial nerve＂ can be achieved during the resection of large acoustic neuroma. Results Total tumor resection was achieved in 79 cases （91.9%）, subtotal resection in 5 （5.8%）, and partial resection in 2 （2.3%）. Anatomic preservation of the facial nerve was achieved in 74 cases （86.0%） and serviceable hearing preservation in 28 cases （32.6%）. Postoperative House-Brackman （H-B） classification was as follows： Grade Ⅰ-Ⅱ in 64 patients （74.4%）, Grade Ⅲ-Ⅳ in 15 （17.4%） and Grade Ⅴ-Ⅵ in 7 （8.2%）. Conclusions ＂Visualizing the facial nerve＂ is critical to preservation of the facial nerve during the resection of acoustic neuroma, simultaneously, a successful surgery also needs perfect microneurosurgical technique and profound anatomical knowledge of cerebellopontine angle.