Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA.
Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA.
Curr Osteoporos Rep. 2020 Dec;18(6):716-726. doi: 10.1007/s11914-020-00640-0. Epub 2020 Nov 20.
We aimed to synthesize the recent work on the intra-vertebral heterogeneity in density, trabecular architecture and mechanical properties, its implications for fracture risk, its association with degeneration of the intervertebral discs, and its implications for implant design.
As compared to the peripheral regions of the centrum, the central region of the vertebral body exhibits lower density and more sparse microstructure. As compared to the anterior region, the posterior region shows higher density. These variations are more pronounced in vertebrae from older persons and in those adjacent to degenerated discs. Mixed results have been reported in regard to variation along the superior-inferior axis and to relationships between the heterogeneity in density and vertebral strength and fracture risk. These discrepancies highlight that, first, despite the large amount of study of the intra-vertebral heterogeneity in microstructure, direct study of that in mechanical properties has lagged, and second, more measurements of vertebral loading are needed to understand how the heterogeneity affects distributions of stress and strain in the vertebra. These future areas of study are relevant not only to the question of spine fractures but also to the design and selection of implants for spine fusion and disc replacement. The intra-vertebral heterogeneity in microstructure and mechanical properties may be a product of mechanical adaptation as well as a key determinant of the ability of the vertebral body to withstand a given type of loading.
我们旨在综合近期关于骨密度、小梁结构和力学性能的椎体内部异质性的研究，探讨其对骨折风险的影响，以及与椎间盘退变的关系，及其对植入物设计的影响。
与椎体周边区域相比，中央区域的骨密度更低，微结构更稀疏。与前区域相比，后区域的密度更高。这些变化在老年人和邻近退变椎间盘的椎体中更为明显。关于沿上下轴的变化以及骨密度异质性与椎体强度和骨折风险之间的关系，报道结果不一。这些差异突出表明，首先，尽管对微观结构的椎体内部异质性进行了大量研究，但对力学性能的直接研究却滞后了，其次，需要更多的椎体加载测量来了解异质性如何影响椎体中的应力和应变分布。这些未来的研究领域不仅与脊柱骨折的问题有关，而且与脊柱融合和椎间盘置换植入物的设计和选择有关。微观结构和力学性能的椎体内部异质性可能是机械适应的产物，也是椎体承受特定类型载荷能力的关键决定因素。
