Yeager Matthew S, Cook Daniel J, Cheng Boyle C
Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA.
Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA ; Department of Neurosurgery, Drexel University College of Medicine, Pittsburgh, PA 15212, USA.
Adv Orthop. 2015;2015:895931. doi: 10.1155/2015/895931. Epub 2015 Aug 17.
Introduction. Pedicle based posterior dynamic stabilization systems aim to stabilize the pathologic spine while also allowing sufficient motion to mitigate adjacent level effects. Two flexible constructs that have been proposed to act in such a manner, the Dynesys Dynamic Stabilization System and PEEK rod, have yet to be directly compared in vitro to a rigid Titanium rod. Methods. Human lumbar specimens were tested in flexion extension, lateral bending, and axial torsion to evaluate the following conditions at L4-L5: Intact, Dynesys, PEEK rod, Titanium rod, and Destabilized. Intervertebral range of motion, interpedicular travel, and interpedicular displacement metrics were evaluated from 3rd-cycle data using an optoelectric tracking system. Results. Statistically significant decreases in ROM compared to Intact and Destabilized conditions were detected for the instrumented conditions during flexion extension and lateral bending. AT ROM was significantly less than Destabilized but not the Intact condition. Similar trends were found for interpedicular displacement in all modes of loading; however, interpedicular travel trends were less consistent. More importantly, no metrics under any mode of loading revealed significant differences between Dynesys, PEEK, and Titanium. Conclusion. The results of this study support previous findings that Dynesys and PEEK constructs behave similarly to a Titanium rod in vitro.
引言。基于椎弓根的后路动态稳定系统旨在稳定病变脊柱，同时允许足够的运动以减轻相邻节段的影响。已提出的两种以这种方式起作用的柔性结构，即Dynesys动态稳定系统和聚醚醚酮（PEEK）棒，尚未在体外与刚性钛棒进行直接比较。方法。对人体腰椎标本进行前屈后伸、侧方弯曲和轴向扭转测试，以评估L4-L5节段的以下情况：完整、Dynesys、PEEK棒、钛棒和失稳状态。使用光电跟踪系统从第3个周期的数据中评估椎间活动范围、椎弓根间距移动和椎弓根间距位移指标。结果。在屈伸和侧方弯曲过程中，与完整和失稳状态相比，器械固定状态下的活动范围有统计学意义的降低。轴向扭转时的活动范围明显小于失稳状态，但不小于完整状态。在所有加载模式下，椎弓根间距位移也发现了类似趋势；然而，椎弓根间距移动趋势不太一致。更重要的是，在任何加载模式下，Dynesys、PEEK和钛棒之间的指标均未显示出显著差异。结论。本研究结果支持先前的发现，即Dynesys和PEEK结构在体外的行为与钛棒相似。
