UCLA

Multiple case reports using recombinant human bone morphogenetic protein-2 (rhBMP-2) have reported complications. However, the local adverse effects of rhBMP-2 application are not well documented. In addition to promoting lumbar spinal fusion through potent osteogenic effects, rhBMP-2 augmentation promotes local cyst-like osteolytic formations in sheep trabecular bones that have undergone anterior lumbar interbody fusion. Conventional computed tomography showed rhBMP-2 application groups could fuse, whereas no fusion was observed in the control group. Micro-computed tomography revealed core implant area’s bone volume fraction and bone mineral density increased proportionately with rhBMP-2. Multiple cyst-like bone voids were observed in peri-implant areas using rhBMP- 2, and these sites showed significant bone mineral density decreases in relation to unaffected regions. Biomechanically, these areas decreased in strength by 32% in comparison with noncystic areas. Histologically, rhBMP-2 affected void sites had an increased amount of fatty marrow, thinner trabecular bones, and significantly more adiponectin and cathepsin K-positive cells. Despite promoting successful fusion, rhBMP-2 use in clinical applications may result in local adverse structural alterations and compromised biomechanical changes to the bone.