乙状窦后入路圆形骨窗开放及内听道区相关结构显微解剖研究

The microsurgical anatomic research of the internal auditory canal area on the retrosigmold approach

目的:对乙状窦后入路圆形骨窗开放及内听道区相关结构进行显微解剖观测,探讨圆形骨窗开放的安全性、可行性及内听道口的定位标志及后壁的磨除范围,为临床听神经瘤手术提供解剖学依据。方法:在15具(30侧)(颅底)10%甲醛固定的正常完整的成人头颅标本上模拟乙状窦后入路圆形骨窗开放及磨除内听道后壁,在手术显微镜下对神经、血管等相关解剖结构进行相关数据测量。结果:15具标本30侧圆形骨窗开放后无一例损伤横窦及乙状窦,骨窗上缘最高点至横窦下缘最低点的垂直距离为(4.02±0.32)mm,骨窗前缘最前点至乙状窦后缘最后点的垂直距离为(6.31±0.43)mm。内听道上结节恒定位于内听道口前上方,内听道结节最高点至内听道口上缘的垂直距离为(2.31±0.32)mm。暴露内听道全程所需磨除内听道后壁的长度及宽度分别为(7.29±0.32)mm和(4.12±0.29)mm,在此磨除范围内,30侧标本中无一例耳蜗、半规管或静脉球损伤。结论:乙状窦后入路圆形骨窗开放方法安全可行,内听道上结节可作为内听道口的定位标志;在暴露内听道时应注意后壁磨除范围,避免损伤耳蜗、半规管或颈静脉球。

Objective：To evaluate the safety of the circular round window and discus anatomic landmarks of posterior wall of internal auditory canal by investigating the microscopic anatomy of internal auditory canal area of the retrosigmold approach,which can provide the anatomical basis for acoustic neutrinomas surgery.Method：Fifteen adult cadaver heads（30sides）fixed with formalin were used in the study.The retrosigmold approach operations were imitated to dissect the blood vessels and nerves in internal auditory canal area by opening round bony window and removing posterior wall of internal auditory canal.Result：Fifteen specimens of 30 sides circular bone window were opened without injury with transverse sinus and sigmoid sinus.The vertical distance between the highest point of bone window margo superior and the lowest point of transverse sinus margo inferior was（4.02±0.32）mm.The vertical distance from the most anterior point of bone window leading edge to the most posterior point of sigmoid sinus trailing edge was（6.31±0.43）mm.The internal auditory canal tubercle located in the anterior superior position of internal auditory canal.The vertical distance from the highest point of internal auditory canal tubercle to the upper margin of internal auditory canal was（2.31±0.32）mm.To expose the whole internal auditory canal,the length and width of the internal auditory canal posterior wall removal was（7.29±0.32）mm,（4.12±0.29）mm.Within this removal range,no case of cochlea,semicircular canal or venous was injured in 30 specimens.Conclusion：The method of opening round window through retrosigmold approach is simple,practial and convenient.With little variation and easiness of location,the sinternal auditory canal tubercle can be used in the identification of the internal auditory canal.When exposing the whole internal auditory canal,the removal scope of the posterior wall should be paid more attention to,in order to avoid the damage of cochlea,semicircular canal and jugular bulb.