Using Finite Element Method To Model And Analyze The Upper Cervical Spine

The upper cervical spine is composed of atlas and axis. It consists of inter-linked joints, the joint capsule and the other ligaments structures. The anatomic structure of upper cervical atlas is vibrant with poor stability. Due to the important structure of being adjacent to the cerebellum, medulla oblongata, cervical spinal, it is vulnerable to fatal damage. With increasing incidence of upper cervical spine injury, understanding and being familiar with the mechanism of upper cervical spine injury will help doctors to evaluate, treat and prevent such injury.In this paper, a system of research technique is established, which combines reverse engineering technology, CT digital image processing,3D CAD technology, computer graphics, the finite element analysis and other areas of the cross subject knowledge. It mainly discusses how to establish the finite element model of cervical vertebra quickly and accurately, and carries on the simulation analysis under different conditions. It provides reference for the cervical vertebra disease clinical diagnosis value, and assists doctors understand the damage mechanism of cervical spine. The doctor can also speculate the particular model of damage.Based on the CT scanning from the normal upper cervical spine, this thesis has got sampling results of DICOM format. Mimics is a three-dimensional reconstruction software. It establishes an upper cervical three-dimensional surface of the mesh model with upper cervical vertebrae, joint capsule, anterior longitudinal ligament, longitudinal ligament, anterior cruciate ligament, alar ligaments through threshold segmentation, region growth, cavity fill etc. Then it carries on the finite element pre-processing, establishes the finite element model of cervical spine, and uses the body of the data obtained from the literature and previous finite element model of simulation data for different torque under the action of the contrast of vertebral rotation angle. The result proves that this model can be used for further cervical spine mechanics performance study. Finally it simulates the extension, lateral bending and axial rotation of the finite element model, and analyzes the results.This paper has three innovations: 1. Compared with the conventional solid modeling, this paper establishes a more practical, more efficient, higher quality and more accurate finite element model to ensure that the final finite element analysis results.2. Based on the masks, the model assigns the materials more accurately and closer to the human body structure with manual selection of suitable areas.3. Based on reverse engineering, the ligament modeling can directly see a ligament of the deformation and stress conditions. Constrained load analysis, this model can be used for precise simulation on cervical spine biomechanics experiment, more intuitive view ligament and state of stress and displacement of the vertebral bodies, and compare clinical lesions in cervical spine with the simulations.