乙状窦前-迷路后入路中内淋巴囊保护的研究

The protection of endolymphatic sac in the presigmoid-retrolabyrithine approach

目的:对前庭导水管外口及内淋巴囊的解剖学位置进行显微解剖研究,探讨乙状窦前-迷路后入路中内淋巴囊保护的方法。方法:应用10例20侧10%福尔马林固定成人头颅标本,显微镜下模拟乙状窦前-迷路后入路手术方法解剖前庭导水管外口及内淋巴囊的位置并进行测量与比较。结果:前庭导水管外口在乳突腔面投影大致位于后半规管弧线前上3mm至其后下3mm的范围内。20例标本内淋巴囊的位置I型占60%(12例),II型占35%(7例),III型占5%(1例)。内淋巴囊尾端可越过乙状窦。磨除后半规管后下的骨质尽量保留3mm。外半规管延长线与乙状窦的交点、岩上窦向前暴露的最前端及乙状窦与岩上窦的交点组成三角形,循三角形的中心向顶点的连线做硬脑膜切口能够保护内淋巴囊的完整。结论:了解前庭导水管及内淋巴囊的具体位置并根据其位置设计切口利于保护内淋巴囊的结构完整和保护听力,利于术后关闭硬脑膜切口。

Objeelive： To study the anatomy of extemal aperture of vestibular aqueduct and endolymphatic sac, and discuss the protective methods of endolymphatic sac in the presigmoid -retrolabyrithine approach. Mothods： 10 cases （20 sides） formalin fixed adult cadaveric heads were used in this study. The extemal aperture of vestibular aqueduct and endolymphatic sac were dissected under surgical microscope according to the presigmoid -retrolabyrithine approach, and the location of external aperture of vestibular aqueduct and endolymphatic sac were measured and compared with canalis semicircularis posterior.Resuits： The projection region of the external aperture of vestibular aqueduct on the wall of mastoid cavity was in an area ranged from the 3 mm anterosuperiorly to the 3 mm posteroinferiorly of the canalis semicircularis. For all cases, type I of endolymphatic sac was about 12 sides, type II 7 sides and type III 1 side. The caudal end of the endolymphatic exceeded the sigmoid sinus. Conclusion： In order to protect the endolymphatic sac during the approach, the posteroinferior part of canalis semicircularis posterior should be kept at lest about 3 mm when stripping it. The cut of endocranium can not exceed the margin of the endolymphatic sac, which is reliable to protect the acouesthesia of patients.