Chou Wen-Kai, Chien Andy, Wang Jaw-Lin
*Institute of Biomedical Engineering, College of Medicine and College of Engineering †Department of Mechanical Engineering, College of Engineering, National Taiwan University, Taipei, Taiwan, ROC.
J Spinal Disord Tech. 2015 Apr;28(3):E121-5. doi: 10.1097/BSD.0000000000000176.
An in vitro fatigue loading test with porcine specimens.
To comparatively analyze the in vitro biomechanical performance of Polyetheretherketone (PEEK) and Titanium rods construct subjected to a battery of fatigue loading testing.
PEEK rods construct has been proposed to allow better load sharing among spinal components than the more traditional Titanium rods constructs. However, such proposal has largely derived from single-load in vitro testing and the biomechanical differences when subjected to fatigue loading remain unknown.
Twenty-four fresh 4-level motion segment were harvested from porcine. Specimens were randomly assigned into 3 groups: (1) intact, (2) destabilized group with Titanium alloy rods, and (3) destabilized group with PEEK rods. All specimens were subjected to a fatigue loading procedure with the disk height and intradiscal pressure (IDP) of the instrumented and adjacent levels were recorded and used for analysis. The stress levels on the rods and bone stress near the screw-bone interface were also collected to investigate the likely failure rates of the 2 constructs.
Titanium rods construct demonstrated a minimum amount of loss of disk height and IDP at the instrumented level; however, a significant loss of the disk height and IDP at adjacent levels compared with the intact spine were identified. In contrast, the disk height and IDP of the PEEK rods were found to be comparable with those of the intact spine for all levels. The PEEK rods group also showed significantly less bone stress near the screw-bone interface compared with the Titanium rods group.
The current study has demonstrated the differences in biomechanical characteristics of PEEK and Titanium rods construct when subjected to fatigue loading. More specifically, the result is indicative of the potential benefits of the PEEK rods construct in reducing the risks of adjacent segment disease and implant failure rates.
对猪标本进行体外疲劳加载试验。
通过一系列疲劳加载试验，比较聚醚醚酮（PEEK）棒与钛棒构建物的体外生物力学性能。
与传统的钛棒构建物相比，PEEK棒构建物被认为能使脊柱各部件之间更好地分担负荷。然而，这一观点主要源于单次加载的体外试验，其在疲劳加载时的生物力学差异仍不明确。
从猪身上获取24个新鲜的4节段运动节段。标本随机分为3组：（1）完整组；（2）钛合金棒失稳组；（3）PEEK棒失稳组。所有标本均接受疲劳加载程序，记录并分析加载节段及相邻节段的椎间盘高度和椎间盘内压力（IDP）。还收集了棒上的应力水平以及螺钉 - 骨界面附近的骨应力，以研究两种构建物可能的失败率。
在加载节段，钛棒构建物的椎间盘高度和IDP损失最小；然而，与完整脊柱相比，相邻节段的椎间盘高度和IDP有显著损失。相比之下，发现PEEK棒在所有节段的椎间盘高度和IDP与完整脊柱相当。与钛棒组相比，PEEK棒组在螺钉 - 骨界面附近的骨应力也显著更低。
本研究证明了PEEK棒和钛棒构建物在疲劳加载时生物力学特征的差异。更具体地说，结果表明PEEK棒构建物在降低相邻节段疾病风险和植入物失败率方面具有潜在益处。
