乙状窦后进路下桥-小脑角的内镜解剖特征

Endoscopic anatomy of the cerebellopontine angle by retrosigmoid approach

目的:了解人体乙状窦后进路下桥-小脑角的内镜解剖层次和特点,并模拟内镜下微血管减压术,为临床开展内镜下微血管减压术奠定基础。方法:对3具尸体头颅的6侧桥-小脑角进行解剖,其中2侧进行开放性解剖,4侧进行了内镜解剖和内镜模拟微血管减压术,手术进路均采用乳突后、乙状窦后进路。结果:由乙状窦后进路观察,桥-小脑角是位于桥脑小脑裂隙的三角锥形潜在区域,密集分布着颅神经和椎基底血管。内镜下由浅入深、由上至下可分为4层,即岩静脉层、面听神经层、三叉神经-外展神经层和低位颅神经层。结论:由于手术通道短而直接、视野清晰,故内镜下微血管减压术治疗三叉神经痛和半侧面肌抽搐宜选用乙状窦后进路,但其有别于传统的手术方式,需在尸体上熟练操作后方能用于临床。

PURPOSE： To describe the general and endoscopic anatomic features of cerebellopontine angle by retrosigmoid approach. METHODES： 3 cadavers（6 sides of cerebellopontine angle） were included in this study. General dissection was carried out in 2 sides, and endoscopic anatomy in 4 sides. Endoscopic microvaseular decompression was performed in 2 sides. Retrosigmoid approach was chosen in all sides. RESULTS： By retrosigmoid approach, the cerebellopontine angle was defined as cone-shaped area that lies between the cerebellopontine fissures with cranial nerves and the vessels of vertibmbasilar system. Discovered by using endoscopy, the CPA was divided into 4 levels： petrosal vein and arachnoid mater, acousticofacial bundle, trigeminal and abducens nerves, and lower cranial nerves（glossopharyngeal, vagus, and accessory）. CONCLUSION： Access to the cerebellopontine angle is easily achieved via the retrosigmoid route, and endoscopic visions can show the structure in great detail and have minimal invasions. Due to the great difference from conventional procedure, doctors must be trained in cadavers before the technique of endoscopic mierovaseular decompression clinically performed.