The Application Of Finite Element Method In Research And Development Of Artificial Cervical Joint Complex

Fusion is the main surgery treatment for degenerative cervical disease, such as the anterior cervical decompression and fusion (ACDF) and subtotal resection of cervical vertebrae for decompression and bone allograft or autograft for cervical fusion。However, the experimental data and clinical cases showed that fusion will change the transfer mechanism of implanted vertebra and speed up the aging of the spine. That is why the Non-fusion is called for. Total disc replacement is the most common one in non-fusion operation, and there are many novel bionic artificial discs on sale. TDR could meet the need of functional reconstruction for anterior cervical decompression and the artificial disc has fidelity. The complications are avoided. However, artificial disc is not proper for the subtotal resection of cervical vertebrae. Thus, designing a novel prosthesis that could meet the need of functional reconstruction for subtotal resection of cervical vertebrae is necessary. For this reason, we developed the artificial cervical joint complex. The biomechanical experimental shows that the novel prosthesis could reconstruct the cervical spine and could maintain the range of the motion of cervical spine. In this research, a three dimension model and finite element model of ACJC was established. The optimal design was conducted based on the finite element analysis method. Modification based on the computational result was made for the ACJC. The applicable value of the FEM in spinal prosthesis was evaluated in the research. The study showed that application of FEM in research and design of medical prosthesis could shorten the period of R&D of prosthesis. The efficiency of R&D could also be improved. Objective: To design and optimize the artificial cervical joint complexity. Method: A three-dimension model of the artificial cervical joint complexity was constructed; we meshed the model based on the finite element method. The feature dimension of bone graft cavity in the model was set in a specified varied range. Under the physical load, we operated a simulation to optimize the feature dimension. We analyzed the stress, strain, and had an evaluation on the systematic safety factor. Result: The simulation showed that the maximum stress appeared in the central area of the inferior of bone graft cavity, the minimum safety factor appeared in the contact area between the superior disc implant and the pad. As the feature dimension got bigger, the maximum strain increased, the graph of minimum safety factor is a Para-curve. Conclusion: Taking the consideration of the systematic constancy and bone graft cavity, the optimal feature dimension of the bone graft cavity is supposed to be 3mm, because the maximum stress becomes the smallest and the systematic safety factor becomes the biggest when the feature dimension is 3mm.