Medtronic's Spinal and Biologics Business, Memphis, TN, USA.
Spine (Phila Pa 1976). 2010 Oct 1;35(21):E1076-82. doi: 10.1097/BRS.0b013e3181df1b85.
Single-level cadaveric lumbar constructs were instrumented with either polyetheretherketone (PEEK) or commercially pure (CP) titanium (Ti) rods and biomechanically evaluated. Strain from gauged bone screws and interbody (IB) spacers, kinematic motion, and caudal disc pressure measurements were recorded during testing.
The objective of this study was to determine the biomechanical differences in CP Ti rods and PEEK rods in conjunction with PEEK interbody spacers.
Very little biomechanical data exist substantiating the performance of PEEK as a spinal rod material. This study is unique, because it combines strain, motion, and pressure measurement techniques to evaluate cadaveric constructs.
Twelve human cadaveric lumbar spine segments (T12-L3 and L4-S1) were tested in compression, flexion-extension, bilateral lateral bending, and bilateral axial torsion. Bending, axial, and shear strains were recorded from a gauged bone screw; axial and shear strains were also recorded from a gauged PEEK interbody spacer. Planar motion data and subadjacent disc pressure measurements were also collected.
Highest screw strains were in bending; the lowest screw strains derived from the shear and axial gauges. Spacer strain was high to medium in some cases, especially in compression and flexion. PEEK constructs attained higher interbody strains than Ti constructs. Conversely, Ti construct screw strains were higher in most tests. Planar motion showed no differences at any level in almost every test. There was a trend toward decreased caudal intradiscal pressure for Ti constructs in compression.
Rigid CP Ti rods resulted in increased screw strain (bone-screw interface forces) and less interbody spacer compression (higher stress shielding). Furthermore, there was a trend toward decreased intradiscal pressure with Ti rods at the caudal segment. These trends suggest that segments instrumented with PEEK more closely mimicked intact physiologic loading in the subadjacent level, which may reduce the likelihood of adjacent level disease.
对单节段尸体腰椎标本进行聚醚醚酮（PEEK）或商用纯钛（Ti）棒的器械固定，并进行生物力学评估。在测试过程中记录了从测量骨螺钉和椎间（IB）间隔器的应变、运动学运动和尾部椎间盘压力测量值。
本研究的目的是确定 CP Ti 棒和 PEEK 棒与 PEEK 椎间间隔器结合时的生物力学差异。
很少有生物力学数据可以证明 PEEK 作为脊柱棒材料的性能。这项研究是独特的，因为它结合了应变、运动和压力测量技术来评估尸体标本。
对 12 个人体尸体腰椎节段（T12-L3 和 L4-S1）进行压缩、屈伸、双侧侧屈和双侧轴向扭转测试。从测量骨螺钉记录弯曲、轴向和剪切应变；从测量 PEEK 椎间间隔器还记录了轴向和剪切应变。还收集了平面运动数据和下位椎间盘压力测量值。
最高的螺钉应变是弯曲；最低的螺钉应变来自剪切和轴向测量仪。在某些情况下，特别是在压缩和弯曲时，间隔器应变较高或中等。PEEK 结构获得的椎间应变高于 Ti 结构。相反，在大多数测试中，Ti 结构的螺钉应变更高。在几乎所有测试中，平面运动在任何水平都没有差异。在压缩时，Ti 结构的尾部椎间盘内压力有下降的趋势。
刚性 CP Ti 棒导致螺钉应变（骨-螺钉界面力）增加和椎间间隔器压缩减少（更高的应力屏蔽）。此外，Ti 棒在尾部节段的椎间盘内压力有下降的趋势。这些趋势表明，与 PEEK 器械固定的节段更接近模拟下位节段的完整生理负荷，这可能降低相邻节段疾病的可能性。
