Paediatric Neck Modelling using Finite Element Analysis

Abstract

This study investigated the external and internal biomechanical responses of the segmented paediatric human cervical spine using the finite element modelling approach. The three-dimensional model of the paediatric cervical spine was obtained by modifying our existing finite element model of the adult spine which was derived from computed tomography and cryomicrotomy. The C4-C5-C6 spine simulated the three vertebrae, the anulus fibrosus and the nucleus pulposus of the interconnecting intervertebral discs, and the ligaments. Appropriate anatomical and material property changes were incorporated to include the paediatric components such as the growth plates and the disc nucleus characteristics. The models were exercised under flexion, extension, lateral bending, and axial torsion load vectors. The responses of the paediatric neck model were compared with the adult neck model responses under these loadings. The external response results indicated the paediatric cervical spine to be more flexible than the adult cervical spine under all four modes; in particular, it was most flexible in the axial torsion mode. In addition, the internal stress responses demonstrated increasing magnitudes. While similar increases were found in the external angular flexibilities and the internal disc stresses between the two models, the vertebral body stresses indicated considerably higher relative changes in the paediatric spine, suggesting a higher role for this component under these vectors. These findings highlight the local component mechanics and the variations in the structural behaviours between the adult and paediatric human cervical spines. The present results are a first step in the analysis of the human paediatric cervical spine biomechanical response and will assist in the design of anthropomorphic child dummies for trauma assessment.