Anisotropic biomimetic trabecular porous three-dimensional-printed Ti-6Al-4V cage for lumbar interbody fusion

Abstract

Lumbar fusion is a popular surgical procedure for the treatment of degenerative lumbar disc disease; however, it may be accompanied by complications, such as cage loosening, subsidence, and non-union. This study engineered and fabricated a three-dimensional (3D)-printed anisotropic biomimetic trabecular porous Ti-6Al-4V cage for lumbar interbody fusion. The study evaluated the structural design, manufacturability, mechanical properties, and cellular functions of the fabricated structures compared to currently available interbody cages. In vitro tests assessed the biofunctionality of the 3D-printed porous cage, which revealed anisotropic biomimetic trabecular porous Ti-6Al-4V cages with 65%-85% porosity, and 600 μm pore size. The microscopy analysis of surface properties indicated in situ micro- and nano-roughness. The mechanical properties decreased progressively with increasing porosity, and the optimized frame-reinforced porous cage achieved higher compressive strength and stiffness than the fully porous fusion. The 70% 3D-printed porous frame-reinforced cage had suitable mechanical performance compared with the polyether-ether-ketone (PEEK) cage. The anisotropic biomimetic trabecular porous structures and the surface micro- and nano-roughness modifications achieved excellent biological functions in vitro. In conclusion, our fabricated 70% 3D-printed porous frame-reinforced Ti-6Al-4V cage with anisotropic biomimetic trabeculae is a promising strategy for lumbar interbody fusion.