体位变换引起腰椎失稳节段在体三维瞬时异常运动的研究

Lumbar instability (LSI) is one of the main causes of low back pain, which usually occurs following postural changes in daily activities, mostly diagnosed by dynamic X-ray. However，dynamic X-ray is able to show sagittal interbody transition and angulation, but rotational and coronal displacement, especially three-dimensional motion of facet joints can not be estimated. As a result, diagnostic criteria of LSI are still under argument. It’s embarrassing that some patients suffer from severe low back pain but fail to fulfill radiological criteria of LSI, while other patients with adequate radiological abnormality may not have any clinical symptoms. In this study, dual fluoroscopic imaging system (DFIS) and CT scan are combined. Lumbar three-dimensional modeling is established by CT scan. Lumbar motion instantaneous images are captured with dual X-ray. Through 2D-3D image matching conversion, in vivo lumbar spine motion (flexion-extension, left-right twisting and left-right bending) is reconstructed. Three-dimensional coordinate system is established on facet joints. Kinematic data (6-degree-of-freedom，6DOF) of instable vertebrae and facet joints under physiological loading are harvested. By comparing the changes in the three-dimensional coordinate system during different activities of the lumbar spine, transient motion characteristics of instable lumbar spine is understood, and meanwhile, a kinematic diagnostic criteria of LSI is established which is closely relative to clinical manifestations.

腰椎节段失稳是腰背痛的常见病因之一，表现为日常活动即可引起剧烈腰痛，诊断需依据动态位腰椎X线片。但因动态位腰椎X线片只能反映单平面腰椎间位移及角度变化，无法观察小关节及椎间旋转等异常情况，导致临床上一些患者虽有失稳症状但影像捕获不到，而另一些影像达到失稳标准又可能没有临床症状，腰椎失稳诊断遭遇困难，源于缺少一种在体位变换时能捕获腰椎在体三维瞬时运动的方法。为了解决这个问题，本研究采用双荧光X线透视和CT结合技术，利用腰椎在体位变化（前后屈伸、左右旋转、左右侧弯）时，形变集中发生在椎间盘、小关节及韧带的特点，通过CT扫描进行腰椎三维建模、双X线透视机同时捕获到双平面的腰椎瞬时运动图像、经2D-3D图像匹配转换、最终重现腰椎在体真实运动情况，获取腰椎失稳小关节及椎体三维运动学数据，并与不同年龄组正常人进行比较，摸索建立不同节段腰椎失稳的三维异常运动诊断标准。