Yoganandan N, Pintar F, Maiman D J, Reinartz J, Sances A, Larson S J, Cusick J F
Department of Neurosurgery, Milwaukee, Wisconsin.
Spine (Phila Pa 1976). 1993 Mar 15;18(4):504-12.
This investigation was conducted to determine the kinematic response of the lumbar spine instrumented with transpedicular screws and plates. Seven unembalmed human cadaveric lumbar spines were used. Retroreflective targets were inserted into the bony landmarks of each vertebral body, facet column, and spinous process. The specimen was quasistatically loaded until failure (initial cycle) using an electrohydraulic testing device at a rate of 2.5 mm/sec. After radiography, the specimen was again loaded (injury cycle) to the failure compression determined in the previous cycle. Transpedicular screws then were inserted bilaterally at one level proximal and distal to injury. The stabilized cycle of loading was conducted using the procedure adopted in the injury cycle. Comparative analysis of the localized kinematic data between the stabilized and injured columns indicated a reduction in motion between fixated levels, increasing the rigidity of the column. At levels proximal and distal to fixation, however, motion increased, indicating added flexibility. These alterations in the motion, observed during single-cycle loading, may be further accentuated in vivo, leading to hypermobility and degeneration of the spine.
本研究旨在确定使用椎弓根螺钉和钢板固定的腰椎的运动学响应。使用了七具未防腐处理的人类尸体腰椎。将反光标记物插入每个椎体、小关节柱和棘突的骨性标志处。使用电动液压测试装置以2.5毫米/秒的速度对标本进行准静态加载直至失效（初始循环）。在进行X线摄影后，将标本再次加载（损伤循环）至在前一循环中确定的失效压缩力。然后在损伤部位近端和远端的一个节段双侧插入椎弓根螺钉。使用在损伤循环中采用的程序进行稳定加载循环。对稳定柱和损伤柱之间的局部运动学数据进行比较分析表明，固定节段之间的运动减少，增加了脊柱的刚度。然而，在固定节段的近端和远端，运动增加，表明灵活性增加。在单循环加载过程中观察到的这些运动变化在体内可能会进一步加剧，导致脊柱活动过度和退变。
