Geometrical evaluation of CAM-configured thermoplastic polyurethane lattices for intervertebral disc replacements

Intervertebral discs (IVD) are prone to deformation due to higher stress that the discs can endure. Treatments for deformed IVDs include total disc replacements. Some studies concluded the superiority of spinal fusion compared to total disc replacement devices, either in the lumbar or cervical region. In current study, cuboid scaffolds made of thermoplastic polyurethane with lattice architecture were designed and configured using computer-aided manufacturing (CAM). The scaffolds were fabricated using fused filament fabrication. Process parameters were characterized and optimized to obtain scaffolds with uniform cells distribution. The struts at the top surface had average width values closer to the setpoints than the struts at the bottom surface, indicated by lower RMSE values for the struts at the top surface. However, the printing consistency in the same extrusion ratio at the bottom surface was higher than at the top surface, indicated by lower standard deviation values. Statistical analysis using standard deviation, RMSE, and Tukey's test showed that current scaffolds had non-uniform distribution between layers, which required further improvement.