Comparative analysis of the subsidence of solid polyetheretherketone (PEEK) and 3D printed lattice titanium interbody fusion cages

Abstract

Spinal interbody fusion cages are commonly used to treat various spinal conditions, but their traditional manufacturing methods have limitations in customization and fitting. With the advancement of 3D printing, it is now possible to design and manufacture interbody fusion cages with previously unachievable features and structures. Southern Medical™ is investigating the technical feasibility of 3D-printed cages based on their existing designs and exploring the new features and capabilities enabled by additive manufacturing (AM). The mechanical performance in the subsidence of the 3D-printed devices will be compared to their existing devices as one of the feasibility points for the additively manufactured implants. A gyroid structure is used as the inner lattice of the structures. To investigate the performance of the cages with the new gyroid lattices, subsidence testing according to the ASTM F2267 methods was conducted to compare existing cages to the 3D-printed cages. The 3D printed devices outperformed the PEEK counterparts with a higher test block stiffness of 0.81 kN/mm compared to 0.55 kN/mm.