Effect of Random Point Seeding in Voronoi Structures on Mechanical Behavior of Cervical Fusion Cages

Porous interbody fusion cages are widely used to improve mechanical compatibility with bone and promote biological fixation. Among various porous designs, Voronoi structures have attracted attention due to their geometric similarity to trabecular bone. However, the randomness of Voronoi lattices raises concerns regarding the sensitivity of their mechanical behavior to stochastic geometric variations. In this study, the effect of structural randomness on the mechanical performance of a porous cervical cage was systematically investigated using finite element analysis. A solid cervical cage was designed and filled with a Voronoi lattice, while the pore size distribution was controlled within a biologically relevant range of ۳۰۰–۶۰۰ µm and manufacturing constraints were satisfied. Ten Voronoi realizations were generated using different random seed point distributions, with all global design parameters kept constant. Finite element analyses were performed under identical static axial compression and boundary conditions representing a physiological loading scenario. Key mechanical parameters, including maximum Von Mises stress, ۹۵th percentile Von Mises stress (P۹۵), axial displacement, and axial stiffness, were extracted and statistically evaluated. The results showed that maximum Von Mises stress exhibits notable variability among different realizations, indicating sensitivity of localized stress concentrations to Voronoi randomness. In contrast, P۹۵ Von Mises stress, axial displacement, and axial stiffness demonstrated low variability, indicating that the global mechanical behavior of the cage is largely insensitive to stochastic lattice variations. Overall, the findings show that Voronoi randomness mainly affects local stress responses, while global load-bearing behavior remains robust, supporting the mechanical reliability of Voronoi-based porous fusion cages.

کلیدواژه ها:

Cervical interbody fusion cage ، Voronoi structure ، Porous implants ، Finite element analysis