Topology Optimization Design Of Interbody Fusion Cage For Personalization

Clinically,interbody fusion therapy during spinal fusion has become the main method to restore iatrogenic spinal instability.Interbody fusion cage have been rapidly developed in theoretical research and clinical application because of their important role in achieving immediate postoperative stability,restoring normal physiological curvature and promoting bone graft fusion.But due to the specification of interbody fusion cage and the patients with pathological conditions don’t match,with uniform size and shape of interbody fusion cage is likely to cause more design for lumbar fusion after sinking,shift,not fusion and so on fusion failure phenomenon(such as traditional bullet type lumbar interbody fusion cage is no longer adapted to the posterior atlanto-axial vertebral reduction and fusion).Therefore,more and more attention has been paid to the design of the fusion cage.How to carry out the specific structural design of the fusion cages for each patient’s special pathological environment and realize the personalized and customized service of the fusion cages is not only of great academic research value,but also of great significance for promoting the development of interbody fusion.In this paper,considering the differences in surgical methods and placement of the fusion cages,the design of the interbody fusion cages was carried out with the help of structural topology optimization.In this paper,the material parameters of the uniform material equivalent model were obtained by using the numerical experimental data and the optimized inversion method.The simplified simulation model can characterize the mechanical characteristics of lumbar vertebrae and atlantoaxial vertebrae,and the force conditions of human body during movement were simulated to verify the effectiveness of the model.Based on this simplified model,topology optimization design was carried out for the implanted interbody fusion device.Under the condition of meeting the requirements of bone graft fusion,the stiffness of the fusion cage was maximized and the settlement of the fusion cage was prevented.Through the design of the structure of the comparative analysis,the new interbody fusion cage obtained has a more uniform stress distribution and reduces the risk of fusion cage settlement,which verifies the design method of patient-oriented personalized customization proposed in this paper.