Vertebral fractures prediction in clinics lacks of accuracy. The most used scores have limitations in distinguishing between subjects at risk or not. Finite element (FE) models generated from computed tomography (CT) of these patients may improve the predictive capability. Many models have already been proposed but the most of them considered the single vertebral body, excluding from the analysis the role of the inter-vertebral discs in the distribution of the load through the spine. Multi-vertebral models instead allow to examine more complex boundary condition. However, CT scans do not provide subject-specif information about the material properties of the disc. Consequently, the goal of the study was to validate a multi-vertebral FE model with subject specific modelling of the vertebral bone and population-based properties assigned to the disc, idealizing them with a linear isotropic material. Boundary condition were assigned in order to reproduce an experimental test performed on the same specimen and recorded using digital image correlation technique (DIC). FE and DIC strains on the vertebral surfaces are compared point-wise. Young's modulus values in the range 25-30 MPa allowed to achieve a comparable order of magnitude between experimental and computational data. However, the two distribution remained strongly different. To conclude, subject-specific material properties need to be assigned also to the discs as well as to the vertebrae to achieve acceptable accuracy in the assessment of the fracture risk.

翻译：临床上椎体骨折预测的准确性不足。最常用的评分方法在区分高危与低危受试者方面存在局限性。基于患者计算机断层扫描（CT）生成的有限元（FE）模型有望提升预测能力。现有研究虽已提出多种模型，但多数仅考虑单个椎体，未纳入椎间盘在脊柱载荷分布中的作用分析。多椎体模型则可考察更复杂的边界条件。然而，CT扫描无法提供椎间盘材料属性的患者特异信息。因此，本研究旨在验证一种多椎体有限元模型，该模型对椎体骨组织采用患者特异性建模，对椎间盘采用基于人群数据集赋予各向同性线性材料属性的理想化处理。通过设定边界条件复现同一标本的实验测试，并利用数字图像相关（DIC）技术记录结果。将椎体表面有限元应变与DIC应变进行逐点比较。当杨氏模量取值在25-30 MPa范围内时，实验数据与计算数据量级相当，但两者的应变分布仍存在显著差异。结论：为实现骨折风险评估的可接受精度，椎间盘与椎体均需赋予患者特异性材料属性。