Numerical analysis of static and dynamic behaviour in an optimized Ti6Al4V Cervical fusion cage produced via additive manufacturing

Abstract

Cervical intervertebral body fusion devices act as space holders between two vertebrae. The cages are used to offer support and stability after surgery. Additive manufacturing is considered an efficient technology for producing medical implants. Ti6Al4V is widely used in the biomedical sector due to its mechanical and chemical characteristics. In this study, a numerical topology optimisation was performed to obtain a porous cage with a lattice structure. The objective was to design biomimetic, lightweight, and customized cages. A numerical study was conducted to determine the performances of the designed porous cages produced by selective laser melting with Ti6Al4V. The numerical design was validated by comparing the numerical results to the experimental one done by a South African company specializing in cervical fusion cage manufacturing. Static and dynamic tests were performed according to ASTM F2067-22 standards to identify the static and dynamic characteristics of the cage under study with the chosen lattice structure and solid fraction. As a result, the lattice structure has an important effect on the residual stress value. The Gyroid lattice structure type with a 45% solid fraction had shown the best performances for the studied cage. According to the ASTM standard and after the static and dynamic tests, the designed cage is accepted since it has passed the tests.