面神经鼓乳段定位及术中面瘫预防

Location of tympanic segment and mastoid segment of facial nerve and prevention of prosopoplegia in operations

目的:根据颞骨解剖结合中耳手术体会,探讨面神经走行定位,避免中耳手术中面神经损伤。方法:用30侧颞骨标本,模拟面神经减压术的手术步骤暴露面神经鼓乳段,确定面神经走行,用易见且恒定的标志进行面神经定位。结果:面神经水平段位于水平半规管与镫骨之间达匙突前上;垂直段位于鼓室后壁,垂直段后缘延长线与水平半规管后1/3相交,夹角为(117.04±2.42)°,其深度位于水平半规管及鼓环平面以下;外膝位于水平半规管前下方。水平半规管中点至面神经最短距离为(1.97±0.53)mm,砧骨短脚至面神经最短距离为(1.03±0.29)mm,匙突至面神经最短距离为(0.93±0.25)mm,镫骨头至面神经最短距离为(1.18±0.42)mm,前庭窗平面鼓沟至面神经的距离为(3.08±0.28)mm,圆窗平面鼓沟与面神经的距离为(2.13±0.34)mm。结论:水平半规管凸、砧骨短脚、镫骨、鼓环及匙突,是面神经鼓乳段理想的定位标志。熟悉面神经走行,可提高中耳手术安全性。

Objective：To study the location of facial nerve and prevent facial nerve injury in middle ear surgery according to dissection of temporal bone and experience of middle ear surgery.Method：Thirty sides of temporal bones were exposed tympanic and mastoid segment of facial nerve with facial nerve decompression.The course of facial nerve was located by the markers of middle ear.Result：Tympanic segment of facial nerve passed between horizontal semicircular canal and stapes,then superior and anterior to the cochleariform process.Mastoid segment of facial nerve located in posterior wall of tympanic cavity.The mastoid segment of facial nerve travelled below the level of horizontal semicircular canal and annulus membranae tympani,and the extension line of its posterior margin and posterior-one-third of horizontal semicircular canal intersected to form an included angle（117.04±2.42）°,. External genu of facial nerve located anterior and inferior to the horizontal semicircular canal.The shortest distance was（1.97±0.53）mm between middle point of horizontal semicircular canal and facial nerve,（1.03±0.29）mm between incus short process and facial nerve,（0.93±0.25）mm between cochleariform process and facial nerve,（1.18±0.42） mm between head of stapes and facial nerve,（3.08±0.28）mm between tympani sulcus and facial nerve at the vestibule window level,and（2.13±0.34）mm between tympani sulcus and facial nerve at round window level,respectively.Conclusion：Horizontal semicircular canal carina,incus short process,stapes,annulus membranae tympani and cochleariform process are ideal landmarks of tympanic and mastoid segment of facial nerve,which are helpful in middle ear surgery.