Specimen-specific Finite Element Modeling of Lumbar Vertebrae: Parametric Study with Experimental Verification

INTRODUCTION Computational modeling of the spine using the finite element (FE) is becoming widely used in the assessment of new orthopaedic procedures. The continual increase in computational power has led to larger and more complex models being developed. However, the verification of the parameters used in the models has been limited. In particular, little work has been undertaken to verify the modeling of bony failure, although this is essential in assessing instrumentation for spinal fracture fixation and vertebroplasty. The parameters associated with FE models fall into two main categories: those relating to the geometry of the model including the FE mesh and boundary conditions, and those relating to the material properties. Whilst some studies have focused on the assessment of individual parameters such as particular material properties [1] or cortical wall thickness [2], little is known about the relative importance of the two parameter categories. The aim of this study was therefore to use specimen-specific and generic FE models of porcine vertebral bodies to investigate the effects of both material property and morphological parameters on FE model predictions by direct comparison with experimental data. A further objective was to investigate if such models could adequately predict the extent of plastic damage within the body following load to failure.