目的 在构建虚拟现实解剖模型基础上探讨枕下乙状窦后入路微创磨除内听道的显微解剖证据。 方法 15例尸体头颅行头颅CT和MRI扫描,影像数据输入虚拟现实系统构建内听道及其周围结构的三维解剖模型。在颅盖和颅底中选择骨性标志点设计枕下乙状窦后入路磨除内听道内不同靶点的微创路径,观察测量和比较伴随路径方向和角度改变,其中解剖结构的显露情况。结果 模拟枕下乙状窦后入路磨除内听道的手术路径中清晰显示所包含的神经、血管等解剖结构的空间层叠顺序。测量和比较显示路径中骨性结构和迷路体积:路径a>路径b>路径c;路径中小脑半球体积:路径b>路径c>路径a;路径中面听神经复合体体积:路径b>路径a>路径c;差异均有统计学意义。结论 在计算机虚拟现实条件下,乙状窦后入路通过磨除岩骨到达内听道末端的模拟微创手术路径能够有效量化手术创伤和靶点显露情况,为手术操作的微创化发展提供指导信息。

Objective To discuss microanatomy features of internal auditory canal through suboccipito-retrosigmoidal minimally invasive approach based on virtual reality image model.Methods CT and MRI scans were performed on fifteen adult cadaver heads, and then, image data were input into Vitrea virtual reality system to establish three-dimensional anatomy model of internal auditory canal and surrounding structures. Different minimally invasive road of suboccipito-retrosigmoidal approaches for drilling of surgical targets in internal auditory canal were simulated by selecting osseous landmark points on the calvaria and skull base. Changes of anatomy exposures were observed, measured and compared following alternation of surgical roads.Results Spacial sequence of nerves and vessels in the route simulating suboccipito-retrosigmoidal approach for drilling internal auditory canal was displayed distinctly. Measurement and comparative analysis showed that volumes of osseous structure and labyrinth involved in route a were the most, and then, volumes involved in route b were more than those in route c. Cerebellar involved in route b was the most, and then, volume of cerebellar involved in route c was more than that in route a. Facial-acoustic nerve complex involved in route b was the most, and then, volume of facial-acoustic nerve complex involved in route a was more than that in route c. The differences of above items reached statistically significant diffecence.Conclusions Assisted by computed virtual reality skill, quantitative evaluation of invasion and target exposure in simulative routes of suboccipito-retrosigmoidal approach drilling petrous bone and reaching terminal of internal auditory canal can be performed to guide minimally invasive surgical practice.