Comparison of a novel demineralized bone fiber allograft with two synthetic bone grafts in the rabbit PLF model

Autologous iliac crest bone graft (ICBG) has been the gold standard of spinal fusion methodology, but ICBG is hindered by donor site morbidity and complications. Alternatives include demineralized bone matrix (DBM) allograft-based products, and synthetic bone grafts (SBG), both of which have been shown to perform similarly to ICBG. Demineralized bone fibers (DBF) present a third option, with elongated fibers of demineralized bone tissue providing similar osteoinduction and improved osteoconduction compared to DBM. The objective of this study was to compare a novel DBF graft to two commercially available SBG products in the standardized rabbit posterolateral fusion (PLF) model. Adult female New Zealand white rabbits underwent bilateral PLF procedures and received the novel DBF graft hydrated in bone marrow aspirate (DBFX + BMA), or one of two commercially available SBG products. Rabbits were sacrificed at 12 weeks post-operation. Lumbar spines were harvested and underwent fusion scoring by manual palpation, radiographic assessment, and micro-computed tomography (microCT) with 3D reconstruction, as well as histopathological analysis. DBFX + BMA resulted in the highest fusion rate by manual palpation (5/8 spines), radiographic assessment (6/8 spines, 12/16 segments), and microCT (7/8 spines, 15/16 segments), compared to both SBG products (0/6 spines by all methods, 1/12 segments by microCT in one group). DBFX + BMA also displayed the most extensive bony remodeling and lowest inflammatory reaction score by histopathological analysis. These data demonstrate that this novel DBF graft may provide better osteoconductive structure and greater fusion outcomes than the SBG products investigated. • Autografts are commonly used for spinal fusion. • Demineralized bone fiber and synthetic bone grafts provide alternatives to autografts. • Demineralized bone fiber has not been extensively compared to synthetic bone grafts. • Demineralized bone fiber showed higher fusion rates than synthetic bone grafts. • Demineralized bone fiber showed lower inflammation than synthetic bone grafts.