Abstract: ObjectiveTo evaluate whether β-tricalcium phosphate (β-TCP) combined with bone marrow mesenchymal stem cells (BMSCs) can be used for lumbar posterolateral spine fusion (PLF) instead of autogenous bone graft. Methods6 crab-eating macaques underwent bilateral PLF at L_4-5, and divided into 3 groups that implanted β-TCP/BMSCs composite, autogenous bone, and β-TCP. Monkeys were sacrificed 12 weeks after implantation. Manual palpation, micro computed tomography, peripheral quantitative computed tomography (pQCT), and histology were used to assess bone formation. ResultsManual palpation showed that 75% of β-TCP/BMSCs composite group and autogenous group achieved solid spine fusion, whereas none of β-TCP group fused. Histological analysis showed that all of the β-TCP/BMSCs group achieved massive bone formation. Bone mineral density (BMD) evaluated with pQCT in the β-TCP/BMSCs group increased by additional new bone. Conclusionβ-TCP/BMSCs composite can be used for PLF instead of autogenous bone graft.

Key words: posterolateral spine fusion, β-tricalcium phosphate, bone marrow mesenchymal stem cells, tissue engineering bone, monkey