中上胸椎水平脊髓减压，因其腹背侧共同压迫和胸脊髓自身缺少侧支循环而术后恢复不理想。对于腹背“钳夹式”压迫的胸椎管狭窄治疗，近年来“涵洞法”环形减压可在早期达到满意临床疗效，但其术后长期随访显示神经功能恢复较早出现停滞。由于术中需要彻底切除骨化硬膜组织方能达到彻底减压，其造成硬脊膜缺损和大量脑脊液外漏而形成术后脑脊液囊肿。这种囊肿对于包绕其中的脊髓是否造成局部压力增高而影响脊髓血供或内环境？国内外研究缺乏此方面论述。本研究希望针对以上问题，通过动物实验建立胸脊髓减压伴有硬脊膜缺损，继发脑脊液囊肿的有限元模型，重点研究囊肿中脊髓-脑脊液力学变化，对脊髓局部压力和血供的影响。这是跨学科协作利用有限元模型对脑脊液病理状态下的系统研究，是以临床难题为切入点的脑脊液囊肿的动物模型有限元分析的基础研究，将完善脊髓-脑脊液相互关系在病理状态下的理论内容。

The spinal cord decompression in upper-mid thoracic spine always do not bring a satisfied post-op recovery due to its ventro-dorsal damage and lack of collateral circulation. The "cave-in" circumferential decompression, aiming at resolving the "cracker" compression of thoracic spinal cord, can realize an early consented clinical outcome. However, its long term post-op follow-up present a rapid retention in neurological recovery. The defect of dural sac seems to be responsable inevitablely since a complete resection of ossified dura is to be achieved, which cause a cerebrospinal fluid (CSF) exudation, moreover, a cerebralspinal fluid cyst. Whether the spinal cord, which is located in centre, is influenced by its surrounding CSF is not proved. Perheps, the rising pressure of fluid will modify its blood supply and inner enviorment. Our research is hoped to establish a finite element analysis model of thoracic spinal cord decompresseion associated with dural sac defect, and a secondary CSF cyst by an animal experiment. The emphasis of our analysis is the mutual function of spinal cord and CSF in the cyst, including the local pressure and blood supply. This is a cooperation of multiple scientific branches focusing on the pathological situation of CSF in finite element model, which is a basic research originating from clinical difficulties. And the results will contribute to the theory of inter-relationship between spinal cord and CSF in pathological circumstances.

本课题为一个跨学科的探索性研究。通过建立胸椎减压的动物模型，试图模拟临床中常见的硬脊膜缺损、继发脑脊液囊肿的模型，同时通过运用三维有限元分析研究此模型的脊髓-脑脊液力学变化。本课题组共完成3例小尾寒羊的动物实验，经后路椎板切除、人为造成硬脊膜缺损，利用磁共振观察术后是否有脑脊液囊肿形成。此外，对实验动物行相位对比电影磁共振（MRI PC cine）检查，测取脑脊液流速；建立三维有限元分析模型，分析脑脊液囊肿中脊髓-脑脊液力学变化。本研究发现，实验动物术后均形成不同程度的后凸畸形，考虑与脊柱后组稳定成份的破坏有关；无脑脊液囊肿的形成，考虑与非直立行走、脑脊液在同一水平流动有关。3D有限元分析发现，脑脊液流动的应力对脊髓的影响轻微，脊髓在此应力下的形变可以忽略不计，脊髓基本处于静水压状态。故认为实验动物术后脑脊液压强的增加与后凸畸形所致的脊髓和脑脊液流道的形变有关系，但目前仍不清除具体机制，仍需进一步研究。