Augmented demineralized bone matrix: a potential alternative for posterolateral lumbar spinal fusion

Variable osteoinductive potential has been reported between and within production lots of different demineralized bone matrix (DBM) products. This study compared fusion rates of different manufactured lots and augmented formulations of DBM with a dose-response curve of recombinant human bone morphogenetic protein 2 (rhBMP-2) on inactivated DBM carrier in a posterolateral fusion rat model. Lumbar fusions were performed in 145 rats. In the control rats, we implanted autograft, graft alternative, including inactivated DBM, or nothing (ie, no graft). In the study rats, we implanted 1 of 2 BioSETR (RTI Biologics, Alachua, Florida) DBM lots, growth factor-enriched DBM, and inactivated DBM plus rhBMP-2 in different concentrations. Manual palpation revealed fusion rates of 25% (autograft), 0% (inactivated DBM), 17% (DBM donor A), and 36% (DBM donor B). The fusion rate of the most enhanced donor B graft (83%) was higher (P<.05) than that of autograft or unenhanced DBM. Inactivated DBM plus rhBMP-2 fused between 45% and 100%. There was no significant difference between DBM plus rhBPM-2 and the highest enrichment group of donor B. Differences between 2 DBM lots in an athymic rat ectopic bone formation model also were found in the spine fusion model. Enhanced DBM formulations were comparable with inactivated DBM plus rhBMP-2 with respect to performance and could represent a bone graft alternative in spine fusion.