| Objective:To construct and validate a three-dimensional upper cervical vertebrae (C0-C3) finite element model and make the first biomechanics analysis to atlas using this model.Methods:We obtained the CT data from a healthy adult man for the regularly health examination. He was checked by radioactive and clinical examination and was proved that he has not any spinal disease. Then his cervical spine was scanned by Siemens Somatom Sensation 64 with 0.6mm thickness without any interval. We get the CT images and save the data with DICOM format. Then the CT images were inputted to the Materialise Mimics and product a 3D surface image of C0-C3 by selecting image, preconditioning and remeshing tools. The 3D image wad inputted to the ANSYS ICEM CFD10.0 with STL format and became a 3D entity, And the element type and material properties were defined at the same time. The 3D entity was inputted to the FEA software-ANSYS10.0, Based on the model of atlas and holo-model of upper cervical vertebrae(C0-C3), The stress of different position of atlas were analyzed when the skull was in neutral, flexion and posterior extension position.Result:The model of C0-C3 was composed of 110105 node points and 91469 elements. Through the stress analysis, no matter which position the skull was, the largest Von Mises stress focused on the anterior arch and the smaller was on the posterior arch and lateral masses.Conclusion:(1) This three-dimensional upper cervical vertebrae (C0-C3) finite element model had similar appearance with reality and can be used for biomechanical study. (2) The axial loading will cause the anterior arch fracture first no matter what position including flexion, median position or posterior extension of the head is. Enough loading or over long time of loading will beget the Jefferson's fracture; The causes for single posterior arch fractures include back extension of head, axial compression on superior joint, atlas posterior arch being pushed upward by occipital bone or axis'spinous and the stress concentrating on the Achille's heel of atlas posterior arch. |
