中耳手术中的面神经定位

Landmark of facial nerve in middle ear surgery

目的结合颞骨解剖和面神经手术，明确适用于手术的面神经解剖标志。方法44具颞骨标本面神经解剖，106例周围性面神经麻痹的面神经减压手术。根据面神经周围的固定解剖标志，确定面神经位置。结果①面神经垂直段标志：水平半规管后中1／3交界处垂直线提示面神经后缘；砧骨短角上缘弧度延长线为面神经垂直段前缘；面神经与水平半规管基本在同一深度；②面神经水平段标志：位于砧骨短突之下；在水平半规管隆突前缘向前上呈30。行走；在匙突后方，面神经与匙突平行形成中上鼓室内侧面交界缘；经过匙突面神经向前上行走到膝状神经节；③膝状神经节定位：从镫骨头到匙突等距离延长线为膝状神经节位置；④鼓索神经定位：鼓索从左侧鼓沟的3点或右侧鼓沟的9点出骨管，沿鼓沟向前行走于砧骨长突外侧和锤骨颈内侧；鼓索神经从面神经发出处距离茎乳孔5—8mm；鼓索位于鼓膜紧张部与松弛部交界处。所有手术所见面神经走向符合解剖所见。结论中耳乳突的固定标志是面神经定位的参照物，其中水平半规管的位置最恒定，根据参照物确定面神经位置提高了手术的安全性。

Objective To re-evaluate landmarks for facial nerve in middle ear surgery through temporal bone dissection and facial nerve surgery. Methods Some relative landmarks were found through 44 facial nerves dissection in cadaver and 106 cases of facial nerve decompression surgery. Results （ 1 ） Landmarks for vertical segment of the facial nerve： the vertical line in combined point between posterior and middle 1/3 horizontal semicircular canal clews file posterior edge of facial nerve; the prolong line of superior radian of incus short process clues to the anterior edge of the facial nerve, the facial nerve and horizontal semicircular canal are almost in the same plane. （2） Landmarks for horizontal segment of the facial nerve ： the facial nerve tracks forward inferior to short process of incus and anterior to horizontal semicircular canal carina in 30 angel. The facial nerve, locating posterior and superior to cochleariform process and parallel with it, forms the step of middle-superior tympanic cavity and tracks forward to geniculate ganglion. （3） location of geniculate ganglion ： The same distance prolong line of stapes head to cochleariform process clues to geniculate ganglion. （4） Location of the chorda tympani nerve ： chorda tympani nerve, leaving tympanic sulcus at 3 clock of bone canalin left ear and at 9 clock of bone canalin right ear, tracks forward along tympani sulcus and then cross between long process of incus and manubrim. It lies in the border of pars tensa and pars flaccida and is about 5-8 mm from the stylomastoid foramen to where the chorda tympani nerve leaves the facial nerve. There is no difference of facial nerve structure in temporal bone dissection and in surgery. Confusions The fixed landmarks of middle ear are the frame of reference of facial nerve, in which horizontal semicircular canal is most invariable; and the safety of surgery will be improved by the reference of the facial nerve.