Abstract

Vertebral fractures cannot currently be predicted accurately in clinics, where the adopted scores have limitations in identifying subjects at risk. In this context, CT-based finite element (FE) models might improve fracture risk prediction. Many proposed FE models consider single vertebrae only, thereby neglecting the role of the intervertebral discs in load transmission and distribution across vertebrae. Multi-vertebrae models would allow the inclusion of more physiological boundary conditions in the simulation thanks to the discs' inclusion. Nevertheless, while CT allows material properties to be assigned to the vertebrae according to the Hounsfield Units, no information about the discs' mechanical properties is provided. Hence, the aim of this study was to validate against experimental data a CT-based multi-vertebrae FE model where linear isotropic material properties were assigned to the discs. The CT-based FE model of a multi-vertebrae specimen was built, where Young’s modulus populations values in the literature range were assigned to the discs. Boundary conditions were assigned coherently with experiments performed on the specimen and the computational strains on the vertebrae surface compared to the experimental strains coming from digital image correlation measurements. The strains on the vertebral surface increased following the increase of the discs' Young’s modulus, with no changes in their local distributions. Although Young’s modulus values around 25-30 MPa yielded comparable orders of magnitude between numerical and experimental strains, strains local distribution differed substantially. In conclusion, subject-specific discs’ material properties should be included in CT-based multi-vertebrae FE models in order to achieve acceptable accuracy in fracture risk assessment. In particular, the dataset contains experimental data obtained using the digital image correlation technique, referred to by the acronym DIC, and the results of finite element model simulations, whose values are given under the acronym FEM, in terms of displacement vectors in the three Cartesian directions (X,Y,Z) and maximum and minimum principal strains. Moreover, the locations (X,Y,Z) of the comparison points on the vertebral surfaces are reported. Also, the identification number (ID) of the comparison points is reported, in this way using the connectivity lists, also reported, it is possible to graphically visualize the data.