Synchrotron Tomography-Based Finite Element Analysis of Vertebral Endplate Loading Reveals Functional Roles for Architectural Features

Lower back pain is linked to vertebral biomechanics, with vertebral endplates (VEPs) playing a key role in vertebral load transfer and distribution. Synchrotron computed tomography (sCT) allows for detailed visualisation of the microstructure of intact VEPs under near-physiological loads and, when coupled with digital volume correlation (DVC), can be used to quantify three-dimensional (3D) strain fields with nanoscale resolution. Herein, we spatially couple DVC data and an image-based finite element model (FEM) to determine the material properties of murine VEPs. This model was then extended to investigate VEP biomechanics under different motions and disease conditions to reveal that VEP protrusions are important for load absorption and redistribution under different motions and predicted that abnormal intervertebral disc (IVD) stress may underpin osteoporosis- and pycnodysostosis-related IVD degeneration. Our study validates the efficacy of using DVC to increase the accuracy of FEM predictions and highlights that these methodologies may be scalable to large animals and humans.