Three-Dimensional Printing of a Spinal Interbody: Design Principles, Biomaterials, and Translational Considerations

Background: Interbody spinal fusion is a common surgical treatment for degenerative, traumatic, and deformity-related spinal pathologies. Despite advances in cage geometry and fixation strategies that improve alignment and early stability, reliable fusion remains limited by the mechanical and biological constraints of conventional interbody implant materials. Traditional titanium and polymer-based cages often fail to optimally balance load sharing, osteointegration, and biological activity within the mechanically demanding interbody environment. This narrative review examines the development and translational potential of 3D-printed interbody fusion devices, with emphasis on how additive manufacturing enables the integration of mechanical performance with biologically active scaffold design. Methods: A thorough literature review was performed to evaluate the evolution, design principles, material properties, and translational outcomes of three-dimensional (3D)-printed interbody fusion devices. Results: Additive manufacturing enables precise control over implant architecture, allowing for the fabrication of porous, lattice-based cages with tunable stiffness, optimized load sharing, and enhanced bone–implant integration. Preclinical and early clinical studies suggest that 3D-printed porous titanium cages may reduce subsidence, promote osteointegration, and improve fusion-related outcomes compared with conventional designs. Emerging evidence indicates that scaffold porosity, surface microtopography, and bioactive coatings influence macrophage polarization, angiogenesis, and osteogenic signaling. Polymeric and composite constructs, particularly hybrid designs incorporating surface functionalization, represent promising adjuncts, though clinical evidence remains limited. Conclusions: Three-dimensional printing represents a paradigm shift in interbody fusion device design. Continued translational research and longer-term clinical follow-up are required to validate efficacy and guide widespread clinical adoption.