立体定向照射兔坐骨神经的CT定位

目的:立体定向照射兔坐骨神经的CT定位。方法:通过解剖分析兔坐骨神经主干的解剖位置和行径,选择照射靶点,放置硅胶管进行标记,按X-刀标准行CT扫描,从CT图像上分析硅胶管与荐骨和髂骨的位置关系,确定可以用骨性结构定位的神经段作为照射靶点,利用立体定向技术单次大剂量照射坐骨神经,观察其病理及超微结构变化。结果:通过解剖可见坐骨神经主干由第7腰神经和第1、2荐神经组成,坐骨神经主干从荐髂关节下、荐骨和髂骨之间穿出后,跨过坐骨大切迹的一段坐骨神经主干位置恒定,且有荐骨和髂骨做定位标志,可作为CT定位的照射靶点,单次大剂量照射后镜下可见神经纤维变性坏死。结论:在CT扫描图像中,利用荐骨和髂骨定位坐骨神经准确可靠,可以作为无创情况下进行立体定向外科研究周围神经放射性损伤的照射靶点。

Location of Rabbit Sciatic Nerve in CT Scanning for Stereotactic Radiosurgery

Objective: To locate of the rabbit sciatic nerve in CT scanning for stereotactic radiosurgery.Methods: By dissecting and tracing the location and course of rabbit sciatic nerve,a 10 mm of the sciatic trunk was selected as a target for further investigation.A silica gel tube was put surround the left sciatic trunk which was selected as a target so as to mark it in CT imaging.The rabbits were immobilized according to the standard of X-knife before CT scanning.The interrelation of the silica gel tube and bony structures was analyzed,a nerve segment was selected,which could be localized according to the related bony structures as irradiation target.A radiosurgery treatment planning was performed on the selected nerve segment,its changes of pathology and ultrastructure were observed.Results: Base on the dissection,the rabbits' sciatic nerve was composed of the seventh lumbar nerve and first and second sacral nerves.The sciatic trunk descended in front of the sacroiliac joint and escaped between the sacral bone and ilium,then left the pelvis from the greater sciatic notch.The segment of sciatic trunk which ran between the sacrum and ilium was stable and feasible for localization according to the related bony structures in CT scanning,so it was selected as irradiation target.After high dose of stereotactic radiation,the degeneration and necrosis in nerve fibers could be observed under microscope.Conclusion: The segment of sciatic trunk which runs between the sacrum and ilium is stable and feasible for localization in CT scanning,and can be chosen as irradiate target in studying peripheral nerve injury by stereotactic radiation technology that is non-invasive method.