Collagen/β-TCP composite as a bone-graft substitute for posterior spinal fusion in rabbit model: a comparison study

β-TCP bioceramic, as a kind of biocompatible and biodegradable artificial bone scaffolds, is increasingly used to supplement lamina autografts when performing instrumented or non-instrumented spinal fusion, clinically, although solid fusion is not always achieved. The addition of collagen to β-TCP appears to be a potential strategy to improve bone regeneration, thereby enhancing the rate of spinal fusion. This study aimed to compare the fusion in collagen/β-TCP composite, β-TCP and autologous bone in a posterior spinal fusion model. The fusion grade evaluated radiography was greater in the collagen/β-TCP group than in the β-TCP group (p < 0.05). Stiffness and yield strength of the fused segments in collagen/β-TCP group were comparable to that in autogenous bone group. Histological analysis revealed that the proportion of new bone formation in collagen/β-TCP group were significantly greater than in β-TCP group (p < 0.05). In addition, bone deposition rate in the collagen/β-TCP group was greater than in the β-TCP group (p < 0.05) and comparable to that in the autogenous bone group. We therefore concluded that collagen/β-TCP is superior to β-TCP alone in facilitating posterior spinal fusion. The addition of collagen to β-TCP represents a simple strategy that couples the osteogenic effect, providing a promising alternative to autologous bone in the clinical treatment of spinal disorders.