Study design: Four groups of 6 animals underwent single-level noninstrumented posterolateral lumbar fusion (PLF) with one of the following grafts: 1) autograft, 2) cell-enriched beta-tricalcium phosphate (TCP), 3) TCP with whole bone marrow, and 4) TCP alone. Plain radiographs were taken after surgery and at death, 6 months after surgery. Explanted spine segments were analyzed by manual palpation, micro-CT, and histology.
Objective: A sheep spine fusion study was undertaken to evaluate the healing performance of a TCP graft enriched with osteoprogenitor cells using Selective Cell Retention technology (SCR), compared with autograft, TCP with whole bone marrow, and TCP alone.
Summary of background data: Improved bone healing with previously demonstrated using grafts enriched in osteoprogenitor cells.
Methods: Cell-enriched grafts were obtained by processing 30 mL of bone marrow through 10 mL of TCP. TCP was also used either saturated with bone marrow or alone.
Results: At 6 months, 33% of the SCR-enriched TCP and 25% of the autograft sites were fused, compared with 8% of the TCP plus whole bone marrow and 0% of the TCP alone. Histology of fused samples showed denser bone formation in the SCR-enriched TCP grafts than in the autograft sites.
Conclusions: The use of SCR-enriched TCP and autograft resulted in similar fusion rates in an ovine posterolateral noninstrumented lumbar spine fusion model.