A new bone surrogate model for testing interbody device subsidence.
A new bone surrogate model for testing interbody device subsidence.
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用于测试椎间装置沉降的新骨替代模型。
DOI：
10.1097/brs.0b013e31820bffe9
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发表时间：
2011
期刊：
影响因子：
3
通讯作者：
Ploeg,Heidi-Lynn
中科院分区：
文献类型：
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作者：
Au,AnthonyG;Aiyangar,AmeetK;Anderson,PaulA;Ploeg,Heidi-Lynn
研究设计：一项体外生物力学研究，调查人工椎骨、聚氨酯泡沫塑料块和人体身体椎体间装置的下沉措施。目的：比较骨替代物和人类椎骨在不同大小/位置的椎间装置的下沉措施。背景数据总结。当人类身体椎体不可用时，骨替代物是可选的。合成椎体模型皮质、终板和松质骨已经被开发作为测试椎间装置下沉的聚氨酯泡沫块的替代品。方法：放置在合成椎体终板、泡沫块和人体椎骨的支撑体受到单轴压缩。用定制的伸长计测量下沉，评估位于终板中央或外围的压痕。根据力-位移曲线确定失败力和压痕刚度。结果：人类椎体的移位测量因压痕放置的不同而不同：压痕周围放置的失败力较大，压痕下沉较少。泡沫块中的下沉措施对压痕的大小/位置不敏感；对于中心放置的压痕，它们类似于人的脊椎，但对于外围放置的压痕，它们与人的脊椎相似。虽然人工椎体的下沉测量对压痕的大小和位置很敏感，但对于中心放置和外围放置的压痕，失败力和压痕刚度被高估了，而沉降量被低估了。结论合成终板正确地代表了人体终板的几何形状，因此，合成椎体中的失败力、刚度和下沉对压痕的大小和放置都很敏感。然而，终板过于坚固，因此合成的椎体不能准确地模拟人类身体椎体的凹陷。对于中心放置的压痕，泡沫块比合成椎骨更准确地捕捉下沉测量，但由于其均匀的密度不足以捕捉不同压痕大小/放置产生的变化。目前的骨替代物在材料性质分布方面还不够准确，不能完全模拟人类身体椎体的下沉。
Study Design.An in vitro biomechanical study investigating interbody device subsidence measures in synthetic vertebrae, polyurethane foam blocks, and human cadaveric vertebrae.Objective.To compare subsidence measures of bone surrogates with human vertebrae for interbody devices varying in size/placement.Summary of Background Data.Bone surrogates are alternatives when human cadaveric vertebrae are unavailable. Synthetic vertebrae modeling cortices, endplates, and cancellous bone have been developed as an alternative to polyurethane foam blocks for testing interbody device subsidence.Methods.Indentors placed on the endplates of synthetic vertebrae, foam blocks, and human vertebrae were subjected to uniaxial compression. Subsidence, measured with custom-made extensometers, was evaluated for an indentor seated either centrally or peripherally on the endplate. Failure force and indentation stiffness were determined from force-displacement curves.Results.Subsidence measures in human vertebrae varied with indentor placement: failure forces were higher and indentors subsided less with peripheral placement. Subsidence measures in foam blocks were insensitive to indentor size/placement; they were similar to human vertebrae for centrally placed but not for peripherally placed indentors. Although subsidence measures in synthetic vertebrae were sensitive to indentor size/placement, failure force and indentation stiffness were overestimated, and subsidence underestimated, for both centrally placed and peripherally placed indentors.Conclusion.The synthetic endplate correctly represented the human endplate geometry, and thus, failure force, stiffness, and subsidence in synthetic vertebrae were sensitive to indentor size/placement. However, the endplate was overly strong and thus synthetic vertebrae did not accurately model indentor subsidence in human cadaveric vertebrae. Foam blocks captured subsidence measures more accurately than synthetic vertebrae for centrally placed indentors, but because of their uniform density were not sufficiently robust to capture changes generated from different indentor sizes/placements. The current bone surrogates are not accurate enough in terms of material property distribution to completely model subsidence in human cadaveric vertebrae.