A novel artificial vertebral implant with Gyroid porous structures for reducing the subsidence and mechanical failure rate after vertebral body replacement

BACKGROUND: Prosthesis subsidence and mechanical failure were considered significant threats after vertebral body replacement during the long-term follow-up. Therefore, improving and optimizing the structure of vertebral substitutes for exceptional performance has become a pivotal challenge in spinal reconstruction. METHODS: The study aimed to develop a novel artificial vertebral implant (AVI) with triply periodic minimal surface Gyroid porous structures to enhance the safety and stability of prostheses. The biomechanical performance of AVIs under different loading conditions was analyzed using the finite element method. These implants were fabricated using selective laser melting technology and evaluated through static compression and subsidence experiments. RESULTS: The results demonstrated that the peak stress in the Gyroid porous AVI was consistently lower than that in the traditional porous AVI under all loading conditions, with a maximum reduction of 73.4%. Additionally, it effectively reduced peak stress at the bone-implant interface of the vertebrae. Static compression experiments demonstrated that the Gyroid porous AVI was about 1.63 times to traditional porous AVI in terms of the maximum compression load, indicating that Gyroid porous AVI could meet the safety requirement. Furthermore, static subsidence experiments revealed that the subsidence tendency of Gyroid porous AVI in polyurethane foam (simulated cancellous bone) was approximately 15.7% lower than that of traditional porous AVI. CONCLUSIONS: The Gyroid porous AVI exhibited higher compressive strength and lower subsidence tendency than the strut-based traditional porous AVI, indicating it may be a promising substitute for spinal reconstruction.