Study design: Prospective randomized study.
Objective: To compare autologous bone marrow concentrate mixed with allograft cancellous bone to iliac crest autograft in lumbar fusions.
Summary of background data: Bone marrow has been shown to be a rich source of osteoprogenitor cells. Osteoprogenitor cells have been shown in animals, and some human studies, to have potential in use as a bone graft substitute.
Methods: Twenty-five patients underwent from 1- to 3-level lumbar fusions. One patient was lost to follow-up. On one half of the spine, allograft plus autologous bone marrow concentrate was used, whereas on the other half, autologous iliac crest bone was used. Cellular analysis, consisting of nucleated cell count, mononuclear cell count, CD34+ count, and colony-forming-units-fibroblast count, was done on marrow aspirates and concentrates. At 1 year postoperation, computed tomographic scans of the fusions were evaluated on a blinded basis by 2 neuroradiologists independent of each other. Radiographical fusion was the primary outcome measure.
Results: There was no statistical difference in fusion scores between allograft and autograft in the lateral gutters, interbody cages, or facet joints. There was a positive trend between CD34+ counts and radiographical fusion.
Conclusion: The study shows equivalence between cancellous allograft mixed with bone marrow concentrate and autologous iliac crest bone for lumbar fusions.
Level of evidence: 2.