乙状窦前经迷路锁孔入路的显微解剖

Microsurgical anatomy of the presigmoid translabyrinthine keyhole approach

目的将微创锁孔理念融入乙状窦前入路,在神经导航辅助下,设计乙状窦前经迷路锁孔入路,观察入路显微解剖,为临床应用提供依据。方法采用8具经福尔马林固定、颅内动静脉乳胶灌注的国人成人尸头,实验前建立术中导航资料。采用迷路后锁孔手术入路的7 cm"C"形切口,分层向前翻开皮瓣和肌筋膜瓣,在神经导航辅助下做耳后约3.5 cm×3.0 cm骨窗,导航下轮廓化乙状窦、骨迷路、面神经管,依次模拟迷路后、经部分迷路及岩尖、经全迷路锁孔入路,观察各步骤显露的结构,测量重要结构长度和术野角度。结果(1)神经导航可辅助精确磨除入路相关骨质,减少盲目磨除造成的重要结构的误伤。(2)同迷路后锁孔入路比较,经部分迷路及岩尖锁孔入路和经全迷路锁孔入路的术野角度、显露的斜坡长度、面神经颅内段长度均有显著增加,但后两种入路的测量值无明显差异。(3)迷路后锁孔入路可保留听力和面神经功能,但对岩斜区的显露有限;部分迷路及岩尖磨除后可广泛显露岩斜区、桥脑小脑角、桥脑前区和海绵窦后部,多角度显露Ⅲ～Ⅺ对脑神经之间的重要结构,且面、听神经功能保有率极高;全迷路磨除后观察角度更多,但进一步增加的显露有限,且需牺牲听力。结论乙状窦前经迷路锁孔入路具有可行性,可良好显露岩斜区等。神经导航可辅助精确完成入路相关的骨质磨除。部分迷路及岩尖或全迷路磨除均可显著增加术野角度和斜坡等重要结构的显露长度,经部分迷路及岩尖锁孔入路可望保留面、听神经功能。

Objective To design a new presigmoid translabyrinthine keyhole approach assisted by Stryker neuro-navigation system according to the keyhole idea, and observe microscopic anatomy structures, which could be regarded as the bases of this approach in clinical application. Methods Navigation data were established on 8 cadaveric heads fixed by formalin and perfused intracranial vessels with colored silicone. A 7-cm postauricular C-shaped skin incision as we reported was performed. After elevating the skin flap and musculofascial flap, a 3.5 cm × 3.0 cm bone window was made. On skeletonizing the sigmoid sinus, bony labyrinth and the canal for facial nerve, the presigmoid retrolabyrinthine, partial labyrintbectomy with petrous apicectomy, translabyrinthine keyhole approaches were simulated in turn. The length of important structures exposed and the angle of vision were measured step by step, and the anatomic structures were observed. Results The approach-correlated bone could precisely be drilled with the aid of neuro-navigation, which could avoid the bewilder in drilling process. The angles of visual field, the length of clivus and Ⅶ cranial nerve were significantly increased after partial labyrintbectomy with petrous apicectomy or all labyrinth removal, but there were no significant difference between partial and all labyrinth removal. The retrolabyrinthine keyhole approach spares hearing and facial function but provided for limited window of petroclival region exposure. The partial labyrinthectomy with petrous apicectomy keyhole approach provided wider exposure to petroclival region, cerebellopontine＇angle, prepontine region and posterior cavernous sinus; an area between the Ⅲ - Ⅺ cranial nerves was easily visible with an excellent chance of hearing and facial nerve preservation. The translabyrinthine keyhole approach, producing more morbidity, provided for greater versatility in treating lesions, added little exposure of petroclival region. Conclusion The presigmoid translabyrinthine keyhole approach, which could provide excellent exposure of the petroclival region, was feasible to be performed in our study. The approach-correlated bone could be precisely removed assisted by neuro-navigation system. The exposure was obviously increased by partial labyrinthectomy with petrous apicectomy or all labyrinthine removal, the former provided an excellent chance of hearing and facial nerve preservation.