鼓岬区底转骨螺旋板的分段定位及其临床意义

Applied anatomic study on lamina spiralis below promontory for cochlear implantation

目的:为耳蜗植入术提供耳蜗鼓岬区底转骨螺旋板的解剖资料,同时寻找从鼓岬表面定位骨螺旋板的方法。方法:取成人颞骨标本15例(30侧),经乳突后鼓室进路,进入鼓室;在手术放大镜下对鼓岬区骨螺旋板走行、分段及毗邻结构进行观测。结果:①耳蜗底转骨螺旋板在鼓岬区可通过位于蜗窗龛上缘及下部的转折点分成3段:钩段(1.52±0.16)mm,蜗窗前下段(3.83±0.37)mm和前行段(2.70±0.36)mm;②蜗窗前下段所在平面与面神经水平段成角为(51.00±5.97)°,且较恒定地与镫骨头后缘相交;以镫骨头后缘为一固定点,在鼓岬上画一经过此点与面神经水平段成51°的直线,可代表骨螺旋板蜗窗前下段在鼓岬上的投影,也即此段骨螺旋板在鼓岬上的投影线;③鼓岬区鼓阶宽度:蜗窗龛上缘中点处宽度为(0.36±0.06)mm;蜗窗龛前缘中点处宽度为(0.97±0.14)mm;蜗窗前下3 mm处宽度为(1.24±0.21)mm。结论:①鼓岬区骨螺旋板可通过2个转折点分成3段,即钩段、蜗窗前下段和前行段;②骨螺旋板在鼓岬上的投影线及与毗邻结构的距离可以为人工耳蜗植入术中准确定位鼓阶,避免损伤基底膜提供形态学依据。

Objective：To provide anatomic data for cochlear implantation, and to find the method of locating lamina spiralis（LS）on the surface of promontory. Method： Microanatomical study was carried out on 30 sides of human temporal bones by observing and measuring lamina spiralis below promontory, including its location, course and adjacent structures. Result：（1）The basal turn of lamina spiralis below promontory can be divided into three segments ： the hook segment （ 1.52 ± 0.16） mm, the anteroinferior round window segment （3.83 ± 0.37） mm and the forwarding segment （2.70 ± 0.36）mm by two hinge points of which one was located at anterior of the junction of superior margin and anterior border of RW, and the other was located at anteroinferior of the round window;（2）The plane of round window anteroinferior segment of LS lay（ 51.00 ± 5.97） degrees anteroinferior to horizontal segment of the facial nerve and comparative permanently meet posterior margin of stapes head. Made posterior margin of stapes head as a fixation point and draw a line on promontory lay （51.00±5.97）degrees anteroinferior to horizontal segment of the facial nerve. This line can be thought as the projection of anteroinferior round window segment of LS on promontory; （3）The width of scala tympani at cochleostomy site on promontory： width of scala tympani at midpoint of superior margin of round window was （0.36± 0.06）mm; width of scala tympani at midpoint of anterior border of round window was （0.97±0.14）mm; width of scala tympani at 3 mm point of anteroinferior round window segment was （1.24 ± 0.21）mm. Conclusion： （1）The basal turn lamina spiralis below promontory can be divided into three segments （ the hook segment, the anteroinferior round window segment and the forwarding segment） by two hinge points; （2）The projection of anteroinferior round window segment of LS and the features exhibited in its course provide reference for locating the basal turn scala tympani and offer reliable anatomical basis for minimal invasive intervention during cochlear implantation.