Finite element modeling and static/dynamic validation of thoracolumbar-pelvic segment.

Finite element method is an efficient tool to investigate the biomechanics of human spine. The key to finite element method is to reconstruct a complete and accurate finite element model. In this study, a three-dimensional finite element model of thoracolumbar structure including complete pelvis (T12-pelvis) was built using computed tomography technology. The modeling process has been explained in detailed. During the process of validation, the model was assigned with non-linear material property for static or dynamic analyses. In static analysis, the vertebral geometry parameters of T12-L5, the axial displacement, the posterior disc bulge and the intradiscal pressure of intervertebral disc, range of motion under six loading cases and facet joint forces were obtained and compared with the experimental data. In dynamic analysis, motion segments were loaded with sinusoidal displacement at 1 Hz in the anterior-posterior and axial directions to verify the reaction force. The first-order resonant frequencies in the vertical direction from one motion segment and two motion segments to the entire model were obtained. The study provides a detailed and accurate method of validation to verify the finite element model of thoracolumbar spine.