Parametric FE mesh generation: application to the cervical spine

A voxel-based reconstruction algorithm, targeted at the generation of finite element (FE) meshes of structures with schematic geometry, is presented. The algorithm is able to generate three dimensional fully hexahedral FE meshes of structures composed of volumes with a schematic geometry. In order to be meshed, each volume must be described in terms of a set of surfaces which enclose the volume. Due to its schematic nature, the method allows the generation of fully parameterized FE models, thus it facilitates the investigation of the mechanical relevance of geometrical parameters by speeding up the mesh generation process. The algorithm was employed in the automatic construction of an FE model of the C3-C7 spinal segment with schematic geometry, made up exclusively of hexahedral elements. Non-linear simulations were carried out in different loading conditions: flexion- extension, lateral bending and axial rotation. The results were compared to data retrieved from the literature in order to ensure the validity of the model. Moment-rotation curves for each loading condition were determined. The range of motion was obtained for each spinal unit and loading condition. Both principal and coupled rotations were determined in lateral bending and axial rotation, for each spinal unit. The intradiscal pressure was also computed in the nucleus pulposus, for all the intervertebral levels. Geometrical parameterization of the models offers potential for the biomechanical investigation of pathologic conditions and surgical procedures, such as spinal fusion and disc arthroplasty, even on a patient-specific basis.