听神经瘤的微侵袭外科治疗

Minimally invasive neurosurgery for acoustic neuromas

目的改进听神经瘤的手术技巧,减少手术创伤,提高手术效果。方法 58个听神经瘤均经枕下乙状窦后Keyhole入路,在全程电生理监测下应用＂4S（4 steps）＂法切除肿瘤：1S：显露、切开、剥离内耳门周围硬脑膜;2S：磨除内听道后壁,游离其内肿瘤组织,找到面、听神经;3S：囊内彻底切除肿瘤组织,使之＂囊皮化＂;4S：免电凝、无张力顺行剥除＂囊皮＂,保护面、听神经及其血供,会师内耳门,全切肿瘤。结果全组无手术死亡、偏瘫病例。肿瘤全切除57例（98.3%）,面神经解剖保留58例（100%）,听神经解剖保留35例（60.7%）;最后一次随访时面神经功能保留（House BrackmannⅠ~Ⅱ级）48例（82.7%）,有效听力保留19例（32.7%）;术前有残存听力者,有效听力保留17例（40.4%）。结论采用枕下乙状窦后＂Keyhole＂入路、4S法微侵袭技术切除听神经瘤创伤小,肿瘤全切及面听神经功能保留率高。

Objective To modify the neurosurgical technique,minimize the operative invasion and improve the surgical outcome of acoustic neuromas.Methods Through a suboccipital retrosigmoidal keyhole approach（SRKA）,with continuous intra-operating neurophysiological monitoring of the Ⅶ-Ⅷ cranial nerve（CN）function,58 acoustic neuromas were resected under 4 STEPs（4S）：1^st S,to expose and remove the dura surrounding the internal auditory pore（IAP）;2^nd S,to open the internal auditory canal（IAC）,free the tumor and find the Ⅶ-Ⅷ CN inside the IAC;3^rd S,to achieve intracapsular tumor thorough resection and to totally free the residual tumor capsule;4th S,to prepare the neural structures with no bipolar coagulation and meet at the IAP at the very end.Results No cases of death and hemiplegia occurred.Total tumor removal was achieved in 57（98.3%）cases.The Ⅶ CN was anatomically preserved in 58（100%）cases and Ⅷ CN in 35（60.7%）cases.At the last follow-up,the Ⅶ CN（H-B grades Ⅰ and Ⅱ）func-tional preservation was achieved in 48（82.7%）cases and the Ⅷ CN in 19（32.7%）cases.Among the patients with hearing before operation,17 cases had functional preservation of the Ⅷ CN,accounting for 40.4%.Conclusions SRKA and 4S may be one of the minimally invasive ways with reasonably high functional preservation rate of Ⅶ-Ⅷ CN for acoustic neuro-mas.