Abstract: Objective  To discuss microanatomy features of facial-acoustic nerve complex in suboccipito-retrosigmoidal minimally invasive approach based on virtual reality image model. Methods  CT and MRI scans were performed to 5 adult cadaver heads, and then, image data was inputted into Vitrea virtual reality system to establish three-dimensional anatomy model of facial-acoustic nerve complex. Suboccipito.retrosigmoidal approach was simulated by selecting osseous landmark points on the calvaria and skull base. Anatomic exposures in surgical trajectory were observed and measured following minimally invasive design. Statistical comparison was launched by paired t test. Results  Routes simulating suboccipito-retrosigmoidal approach for exposure of facial-acoustic nerve complex passed under the inferior edge of transverse sinus. Spacial sequence of nerves and vessels in the route was displayed clearly. Vertebral artery and posterior inferior cerebellar artery did not show in the route. Cerebella, lower cranial nerves, anterior inferior cerebellar artery, facial-acoustic nerve complex were exposed successively in route before minimally invasive design. Then, lower cranial nerves pierced the jugular foramen at the site between the jugular bulb and inferior petrosal sinus. Minimally invasive route was higher than that before minimally invasive design and involved cerebella, anterior inferior cerebellar artery and facial-acoustic nerve complex successively. Lower cranial nerves and jugular bulb were not shown in minimally invasive route. Measure and comparative analysis showed that volumes of route (t = 36.331, P = 0.000) and cerebella (t = 16.775, P = 0.000) involved before minimally invasive design were more than that after minimally invasive design with statistically significant difference. Comparison did not show significant differences for the volumes of facial-acoustic nerve complex (t = 1.680, P = 0.127) and anterior inferior cerebellar artery (t = 1.278, P = 0.233) between routes before and after minimally invasive design. Conclusions  Minimally invasive routes of suboccipito-retrosigmoidal approach can reduce surgical injury without sacrifice of anatomic exposure for facial-acoustic nerve complex.

Key words: Cerebellopontine angle, Facial nerve, Cochlear nerve, Microsurgery

摘要： 目的  在构建虚拟现实解剖模型基础上，探讨经枕下乙状窦后入路微创显露面听神经复合体的显微解剖学特征。方法 共5 具（10 侧）尸头标本通过CT 和MRI 扫描数据经虚拟现实系统构建面听神经复合体三维解剖影像模型，于颅盖和颅底选择骨性标记设计经枕下乙状窦后入路手术路径，观察和测量微创化前后解剖结构显露情况。结果 模拟经枕下乙状窦后入路由横窦下方穿过，可清晰显示其所包含解剖结构的空间层叠顺序，不包含椎动脉和小脑后下动脉。微创化前手术路径由外向内依次显露小脑半球、后组脑神经、小脑前下动脉、面听神经复合体，于岩骨背面、面听神经复合体下方后组脑神经在颈静脉球和岩下窦之间穿出颈静脉孔；微创化后手术路径位置略高于微创化前，由外向内依次显露小脑半球、小脑前下动脉和面听神经复合体，不包含后组脑神经和颈静脉球。微创化前手术路径体积（t = 36.331，P = 0.000）和小脑半球体积（t = 16.775，P = 0.000）均大于微创化后，且差异有统计学意义；微创化前后手术路径中所显露的面听神经复合体体积（t = 1.680，P = 0.127）和小脑前下动脉体积（t =1.278，P = 0.233）差异无统计学意义。结论 经枕下乙状窦后入路微创化手术路径能够在保证面听神经复合体解剖显露的情况下减少手术创伤。

关键词: 小脑脑桥角, 面神经, 耳蜗神经, 显微外科手术