Finite element analysis of vertebral body mechanics with a nonlinear microstructural model for the trabecular core

in this study, a finite element model of a vertebral body was used to study the load-bearing role of the two components (shell and core) under compres sion. The model of the vertebral body has the characteristic Kidney shape t ransverse cross section with concave lateral surfaces and flat superior and inferior surfaces. A nonlinear unit cell based foam model was used for the trabecular core. where nonlinearity was introduced as coupled elasto-plast ic beam behavior of individual trabeculae. The advantage of the foam model is that architecture and material properties are separated thus facilitatin g studies of the effects behavior Stiffness changes with age (architecture and porosity changes) for the trabecular decreases with increasing age and lateral,wall curvature. Elasto-plastic (nonlinear) analyses showed that fai lure regions were concentrated in the upper posterior region of the vertebr a in both the shell and core components. The ultimate load of the vertebral body model varied from 2800 N to 5600 N, depending on age (architecture an d porosity of the trabecular core) and shell thickness. The model predictio ns lie within the range of experimental results. The results provide an und erstanding of the relative role of the core and shell in vertebral body mec hanics and shed light on the yield ann post-yield behavior of the vertebral body.