Department of Neurosurgery, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA 52242, USA.
Department of Biomedical Engineering, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.
J Clin Neurosci. 2014 Apr;21(4):651-5. doi: 10.1016/j.jocn.2013.08.010. Epub 2013 Sep 7.
Spinal instrumentation and fusion have been incriminated as contributing to adjacent segment degeneration (ASD). It has been suggested that ASD results from increased range of motion and intradiscal pressure (IDP) adjacent to instrumentation. Posterior dynamic stabilization with polyetheretherketone (PEEK) rods has been proposed as potentially advantageous compared to rigid instrumentation with titanium (Ti) rods in reducing the incidence of ASD. We evaluated segmental motions in the cadaveric spine instrumented with PEEK or Ti rods from L3 to S1, as well as the adjacent segment motions and IDP at L1-2 and L2-3. Human cadaveric spines were potted at T12-L1 and S1-2. Spinal instrumentation from L3-S1 was accomplished using pedicle screws with either PEEK or Ti rods. Specimens were subjected to displacement controlled testing: 15° flexion, 15° extension, 10° lateral bending, and 5° right axial rotation using the MTS machine (MTS, Minneapolis, MN, USA). Intradiscal pressure was measured by placing pressure transducers into the intervertebral disc at L1-2 and L2-3. Spinal motion of L2 relative to L3, and L3 relative to S1 was tracked using a three dimensional motion analysis system. Instrumentation with PEEK and Ti rods was associated with a decrease in L3-S1 motion compared to the intact state that was significant in flexion (p=0.002), and extension (p=0.0075). Instrumentation with PEEK and Ti rods was associated with an increase in IDP at L1-2 that was significant in flexion (p=0.0028). Instrumentation with either PEEK or Ti rods resulted in decreased motion at the instrumented levels while increasing IDP at the adjacent level.
脊柱内固定融合术被认为与邻近节段退变（ASD）有关。有人认为，ASD 是由于器械邻近节段活动度和椎间盘内压力（IDP）增加所致。与钛（Ti）棒刚性固定相比，聚醚醚酮（PEEK）棒后路动态稳定被认为具有降低 ASD 发生率的潜在优势。我们评估了从 L3 到 S1 植入 PEEK 或 Ti 棒的尸体脊柱的节段运动，以及 L1-2 和 L2-3 相邻节段的运动和 IDP。人体尸体脊柱在 T12-L1 和 S1-2 处进行了盆式固定。L3-S1 的脊柱内固定采用椎弓根螺钉和 PEEK 或 Ti 棒完成。标本采用 MTS 机器（明尼苏达州明尼阿波利斯市 MTS 公司）进行位移控制测试：15°屈曲、15°伸展、10°侧屈和 5°右侧轴向旋转。通过在 L1-2 和 L2-3 椎间盘内放置压力传感器测量椎间盘内压力。使用三维运动分析系统跟踪 L2 相对于 L3 和 L3 相对于 S1 的脊柱运动。与完整状态相比，PEEK 和 Ti 棒内固定与 L3-S1 运动减少相关，在屈曲时（p=0.002）和伸展时（p=0.0075）具有显著意义。PEEK 和 Ti 棒内固定与 L1-2 处 IDP 增加相关，在屈曲时（p=0.0028）具有显著意义。PEEK 或 Ti 棒内固定在增加邻近节段 IDP 的同时减少了器械节段的运动。
