新型双向自锁定型融合器的体外生物力学评价

Biomechanical evaluation of a new bidirectional self-locking fusion device in vitro

中文关键词:  生物力学  脊柱  自锁定融合器  双向

英文关键词:Biomechanics  Spine  Self-locking fusion device  Bidirectional

中文摘要:

  【摘要】 目的：对自主研制的一种新型双向自锁定型融合器进行体外生物力学评价。方法：将12具新鲜家猪脊椎L3/4节段标本随机分为三组进行造模，包括为正常组（完整状态），传统融合器组（传统融合器＋单侧螺钉固定）和新型融合器组（置入双向自锁定型融合器），每组4具标本在MTS多自由度（脊柱运动）模拟测试系统以及500N预载荷基础上，对实验标本各方向依次施加8N·m载荷，按照前屈、后伸、左侧弯、右侧弯、左右旋转的顺序进行稳定性测试，比较各组模型在不同工况下的腰椎活动度（range of motion，ROM）。应用TT-JQ-01-106疲劳试验机进行轴向疲劳压缩试验，观察新型双向自锁定型融合器的稳定性和可靠性。结果：新型融合器组与正常组相比，在前屈（1.67°±0.65° vs 3.46°±0.16°）、后伸（1.43°±1.01° vs 1.89°±0.29）°、左侧弯（2.07°±1.32° vs 3.08°±0.09°）、右侧弯（1.38°±0.72° vs 4.37°±0.20°）、右旋（2.17°±1.51° vs 5.10°±0.37°）工况下ROM降低，差异具有统计学意义（P＜0.05）；在左旋工况下，新型融合器组ROM值（3.10°±1.57°）显著高于正常组（2.36°±0.62°）（P<0.05）。新型融合器组与传统融合器组相比，在前屈（1.67°±0.65° vs 1.22°±0.76°）和左旋（3.10°±1.57° vs 1.57°±0.91°）工况下的ROM显著升高（P<0.05）；而在后伸（1.43°±1.01° vs 1.06°±0.50°）、左侧弯（2.07°±1.32° vs 1.87°±1.41°）、右侧弯（1.38°±0.72° vs 1.45°±0.69°）及右旋（2.17°±1.51° vs 1.69°±1.07°）工况下，两组间ROM无显著性差异（P＞0.05）。正常组前屈、后伸、左侧弯、右侧弯、右旋工况下ROM 均显著高于其余两组（P<0.05）。疲劳试验：经500万次载荷-位移循环后，肉眼观察未发现融合器变形或裂缝，轴向压缩疲劳测试通过。结论：双向自锁定型融合器可明显提高融合节段的稳定性，其稳定效果相当于使用后路单侧钉棒系统，且具有良好的抗疲劳性，在力学性能上可以满足临床应用的需求。

英文摘要:

  【Abstract】 Objectives: To evaluate the biomechanics of a new self-developed bidirectional self-locking fusion device in vitro. Methods: 12 fresh L3/4 segment specimens of domestic pig spine were randomly divided into 3 groups for modeling: normal group(intact state), traditional fusion device group(traditional fusion device and unilateral screw fixation) and new fusion device group(bidirectional self-locking fusion device implanted). On the basis of MTS multi-freedom(spinal motion) simulation test system and 500N preload, 8N·m load was applied to experimental specimens in each direction successively, and the stability test was carried out according to the order of forward bending, backward extension, left bending, right bending, and left and right rotation. The ranges of motion(ROMs) were compared between groups under different working conditions. The axial fatigue compression test was carried out with TT-JQ-01-106 fatigue testing machine to evaluate the stability and reliability of the self-developed fusion device. Results: Compared with the normal group, the ROM of the new fusion device group was significantly decreased under the conditions of flexion(1.67°±0.65° vs 3.46°±0.16°), extension(1.43°±1.01° vs 1.89°±0.29°), left bending(2.07°±1.32° vs 3.08°±0.09°), right bending(1.38°±0.72° vs 4.37°±0.20°), and right rotation(2.17°±1.51° vs 5.10°±0.37°)(all P<0.05); Under the left rotation condition, the ROM value(3.10°±1.57°) of the new device group was significantly higher than that of the normal group(2.36°±0.62°)(P<0.05). Compared with the conventional fusion device group, the ROM of the new fusion device group was significantly increased under flexion(1.67°±0.65° vs 1.22°±0.76°) and left rotation(3.10°±1.57° vs 1.57°±0.91°) conditions(P<0.05); However, there were no significant differences in ROMs between the two groups under extension(1.43°±1.01° vs 1.06°±0.50°), left bending(2.07°±1.32° vs 1.87°±1.41°), right bending(1.38°±0.72° vs 1.45°±0.69°), and right rotation(2.17°±1.51° vs 1.69°±1.07°) conditions(P>0.05). The ROM values of the normal group under flexion, extension, left bending, right bending, and right rotation conditions were significantly higher than those of the other two groups(P<0.05). Fatigue test: after 5 million load-displacement cycles, visual inspection revealed no deformation or cracks in the fusion device, and the axial compression fatigue test was passed. Conclusions: The bidirectional self-locking fusion device can obviously improve the stability of the fusion segment, which is equivalent to the stability of using the posterior single-sided nail rod system, meanwhile, it has good fatigue resistance, therefore its mechanical properties can meet the needs of clinical applications.