A biomechanical comparative study of cervical spine finite element model using hexahedral mesh and tetrahedral mesh

The human cervical spine is a unique structure which connects the cranium and the thoracic region. The intervertebral disc serves as a weight bearing, supports the body and allows the relative motion between the vertebrae. The objective of this work is to compare the influence of hexahedral mesh vs tetrahedral mesh in cervical spine and its effect to measure the biomechanical stresses and its motion at different motion segments. The model was meshed using linear hexahedral mesh and linear tetrahedral mesh. A compressive load of 50 N preload and a moment of 1 Nm is applied at the C3 vertebrae and at the C6 vertebra bottom is fixed in all the directions. The models were used to study the physiological range of motion of the cervical spine. Flexion, extension, lateral bending and axial rotation were simulated. The physiological range of motion and the intervertebral disc stress distribution is studied and compared with the existing in vitro and in silico studies. In this model it was observed that the linear hexahedral and the linear tetrahedral models surrogate the physiological motion. We found the results of the two different meshes were validated with the existing in vitro and in silico studies. The main finding of this work is both hexahedral and tetrahedral mesh have the capability to replicate the natural phenomenon. In this we conclude the tetrahedral mesh is easy to generate and the irregular anatomy of the cervical spine can be modelled and analysed.