Wang Tian, Ball Jonathon R, Pelletier Mattew H, Walsh William R
Surgical & Orthopaedic Research Laboratories, Prince of Wales Clinical School, University of New South Wales, Clinical Science Bldg, Prince of Wales Hospital, Gate 6, Avoca Street, Sydney, 2031, Australia.
Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia.
J Exp Orthop. 2014 Dec;1(1):3. doi: 10.1186/s40634-014-0003-z. Epub 2014 Jun 26.
Laboratory spinal biomechanical tests using human cadaveric or animal spines have limitations in terms of disease transmission, high sample variability, decay and fatigue during extended testing protocols. Therefore, a synthetic biomimetic spine model may be an acceptable substitute. The goal of current study is to evaluate the properties of a synthetic biomimetic spine model; also to assess the mechanical performance of lateral plating following lateral interbody fusion.
Three L3/4 synthetic spinal motion segments were examined using a validated pure moment testing system. Moments (±7.5 Nm) were applied in flexion-extension (FE), lateral bending (LB) and axial rotation (AR) at 1Hz for total 10000 cycles in MTS Bionix. An additional test was performed 12 hours after 10000 cycles. A ±10 Nm cycle was also performed to allow provide comparison to the literature. For implantation evaluation, each model was tested in the 4 following conditions: 1) intact, 2) lateral cage alone, 3) lateral cage and plate 4) anterior cage and plate. Results were analysed using ANOVA with post-hoc Tukey's HSD test.
Range of motion (ROM) exhibited logarithmic growth with cycle number (increases of 16%, 37.5% and 24.3% in AR, FE and LB respectively). No signification difference (p > 0.1) was detected between 4 cycles, 10000 cycles and 12 hour rest stages. All measured parameters were comparable to that of reported cadaveric values. The ROM for a lateral cage and plate construct was not significantly different to the anterior lumbar interbody construct for FE (p = 1.00), LB (p = 0.995) and AR (p = 0.837).
Based on anatomical and biomechanical similarities, the synthetic spine tested here provides a reasonable model to represent the human lumbar spine. Repeated testing did not dramatically alter biomechanics which may allow non-destructive testing between many different procedures and devices without the worry of carry over effects. Small intra-specimen variability and lack of biohazard makes this an attractive alternative for in vitro spine biomechanical testing. It also proved an acceptable surrogate for biomechanical testing, confirming that a lateral lumbar interbody cage and plate construct reduces ROM to a similar degree as anterior lumbar interbody cage and plate constructs.
使用人体尸体或动物脊柱进行的实验室脊柱生物力学测试在疾病传播、高样本变异性、长时间测试方案中的衰减和疲劳方面存在局限性。因此，合成仿生脊柱模型可能是一种可接受的替代方案。本研究的目的是评估合成仿生脊柱模型的特性；同时评估椎间融合后外侧钢板的力学性能。
使用经过验证的纯力矩测试系统对三个L3/4合成脊柱运动节段进行检查。在MTS Bionix中，以1Hz的频率在屈伸（FE）、侧弯（LB）和轴向旋转（AR）方向施加±7.5 Nm的力矩，共进行10000个周期。在10000个周期后12小时进行额外测试。还进行了±10 Nm的周期测试以与文献进行比较。为了进行植入评估，每个模型在以下4种条件下进行测试：1）完整状态，2）仅外侧椎间融合器，3）外侧椎间融合器和钢板，4）前路椎间融合器和钢板。结果采用方差分析和事后Tukey's HSD检验进行分析。
活动范围（ROM）随周期数呈对数增长（AR、FE和LB方向分别增加16%、37.5%和24.3%）。在4个周期、10000个周期和12小时休息阶段之间未检测到显著差异（p>0.1）。所有测量参数与报道的尸体值相当。外侧椎间融合器和钢板结构的ROM在FE（p = 1.00）、LB（p = 0.995）和AR（p = 0.837）方面与前路腰椎椎间融合结构无显著差异。
基于解剖学和生物力学相似性，此处测试的合成脊柱为代表人类腰椎提供了一个合理的模型。重复测试并未显著改变生物力学，这可能允许在许多不同的手术和器械之间进行无损测试，而无需担心遗留效应。样本内变异性小且无生物危害使其成为体外脊柱生物力学测试的一个有吸引力的替代方案。它也被证明是生物力学测试的一个可接受的替代物，证实了腰椎外侧椎间融合器和钢板结构与前路腰椎椎间融合器和钢板结构一样能在相似程度上减少ROM。
