应用数字骨科技术研究生理载荷下腰椎相邻椎弓根之间瞬时运动学特性

Lumbar fusion surgery using rigid instrumentation is a widespread and accepted treatment for various lumbar disc degenerative diseases. But, the results of many recent studies have challenged this concept by showing that patients' self-rated improvements in pain and function after surgery are unrelated to the attainment of solid fusion. It is now well accepted that spine fusion changes local biomechanics, which may accelerate disc degeneration adjacent to the instrumented segments. In order to prevent negative effects on the adjacent segments, the use of lumbar posterior dynamic systems has been increasing in clinic, witch is used dynamic elements such as spring to connect the adjacent pedicle screws simulates normal activity. However, in the literature, follow-up results on the application of the technique differs. For example, Grob retrospectively analyzed the 2-years follow-up results of 31 patients in application of Dynesys system , quality of life improved in only 50% of the patients, with 19% requiring reoperation and 3 cases needed revision surgery. So one wonders whether the design of posterior lumbar dynamic fixation systems truly meet the requirements of human lumbar spine kinematics? Due to the limitation of technique, currently there are no published study that has report on the range of motion of the lumbar pedicle under physiologic functional activities, particularly at the lumbar pedicle-screw entrance point. Recently, we have developed and validated a novel combined dual fluoroscopic imaging system (DFIS) and MRI based 2D-3D matching of bony anatomic features technique to measure in-vivo human lumbar vertebral motion under weightbearing conditions . The lumbar spine was then imaged using two fluoroscopes while the subject performed primary flexion-extension, left-right bending, and left-right twisting.The range of motion of the lumbar pedicle-screw entrance point during each activity was determined.The results will aid clinical research as well as design and improvement of posterior lumbar unfusion implants.This method also can test the posterior pedicle screw dynamic fixation systems postoperative whether it meet the requirements of in-vivo 3D kinematics of the body.

腰椎后路动态固定系统是在维持腰椎稳定性同时保留腰椎生理活动功能及延缓融合临近节段退变。由于尚未见腰椎相邻椎弓根之间在体运动范围的数据报道，各种腰椎非融合产品"动态部分"的活动量从2-15 均有，且体外设计参数与术后体内实际活动量也不同。临床发现如果术后体内实际活动过小，不能起到动态固定作用，可活动过大又可能导致医源性腰椎失稳的发生。这种人体在生理载荷下相邻腰椎椎弓根之间三维活动的范围到底是多少？本研究应用数字骨科技术即双X线透视系统（DFIS）和MRI相结合，从MRI获取腰椎三维模型，DFIS获取腰椎双平面X线图像，经2D-3D图像匹配，真实再现出腰椎生理载荷下三维运动状态，经不同腰椎活动体位的采集计算，最终获得生理载荷下腰椎弓根在体运动范围的6DOF数据。研究结果不仅可指导腰椎后路动态固定系统的设计与改进，还可量化评价其临床手术后在患者体内的实际应用效果，研究成果应用前景广泛。

腰椎后路动态固定系统是在维持腰椎稳定性同时保留腰椎生理活动功能及延缓融合临近节段退变。由于尚未见腰椎相邻椎弓根之间在体运动范围的数据报道，各种腰椎非融合产品"动态部分"的活动量从2-15 均有，且体外设计参数与术后体内实际活动量也不同。临床发现如果术后体内实际活动过小，不能起到动态固定作用，可活动过大又可能导致医源性腰椎失稳的发生。这种人体在生理载荷下相邻腰椎椎弓根之间三维活动的范围到底是多少？本研究应用数字骨科技术即双X线透视系统（DFIS）和MRI相结合，从MRI获取腰椎三维模型，DFIS获取腰椎双平面X线图像，经2D-3D图像匹配，真实再现出腰椎生理载荷下三维运动状态，经不同腰椎活动体位的采集计算，最终获得了生理载荷下腰椎弓根在体运动范围的6DOF数据。研究结果不仅可指导腰椎后路动态固定系统的设计与改进，还可量化评价其临床手术后在患者体内的实际应用效果，研究成果应用前景广泛。