Efficacy of Octacalcium Phosphate/Gelatin (OCP/Gel) Composite Implantation for Miniature Swine Lumbar Interbody Fusion

Synthetic octacalcium phosphate (OCP) has emerged as a potential precursor for bone apatite crystals, promoting faster bone formation and better biodegradability compared to hydroxyapatite and β-tricalcium phosphate materials. Combining OCP with various polymeric biomaterials enhances its ductility, making it suitable for clinical applications, including dentistry. Preclinical studies on OCP/gelatin (OCP/Gel) composites have shown excellent osteoconductive and osteoinductive properties, indicating potential for bone defect repairs. This study investigates the efficacy of OCP/Gel as a filler for lumbar interbody fusion cages. A miniature swine model underwent surgery using polyetheretherketone (PEEK) cages with different fillers: no filler, autologous rib, and OCP/Gel. Eight weeks post-surgery evaluations using computed tomography, histological assessments, and Fourier transform infrared (FT-IR) spectroscopy revealed that while PEEK cages without fillers showed no bone fusion, those with autologous rib and OCP/Gel demonstrated partial interbody fusion. Histological analysis indicated new bone growth in cages with OCP/Gel, and FT-IR spectroscopy confirmed the degradation of OCP at the vertebral interface and increased bone matrix proteins. The findings suggest that OCP/Gel could be a viable alternative to autologous bone grafts for lumbar interbody fusion surgeries, offering less invasive and more cost-effective solutions. The success of OCP/Gel in clinical applications could pave the way for broader use in orthopedic reconstructive surgeries, potentially eliminating the need for combined use of bone marrow aspirate or expensive growth factors.