Beta-tricalcium phosphate (beta-TCP) graft combined with bone marrow stromal cells (MSCs) for posterolateral spine fusion.

Macaque lumber posterolateral spine fusion (PLF) was performed by using beta-TCP graft combined with bone marrow derived stromal cells (MSCs), to evaluate whether a beta-TCP/MSCs hybrid can be used for PLF instead of autogenous bone graft. Nine crab-eating macaque underwent bilateral PLF at L4-L5. The implants were divided into three groups: 1) beta-TCP/MSCs hybrid, 2) autogenous bone, and 3) beta-TCP. Six monkeys were sacrified at 12 weeks and three monkeys were sacrificed at 24 weeks after implantation. Manual palpation, radiography, micro computed tomography, peripheral quantitative computed tomography (pQCT), and histology were used to assess bone formation. Manual palpation and X-ray showed that 83.3% of hybrid groups and 66.7% of autogenous groups achieved solid spine fusion, whereas none of other groups fused. Histological analysis showed that all of the hybrid groups achieved massive bone formation. Bone mineral density (BMD) evaluated with pQCT in the hybrid groups increased by additional new bone. Beta-TCP/MSCs hybrid can be used for PLF instead of autogenous bone graft. Thus it can be hypothesized that the monkey PLF can simulate human PLF.