Anterior Lumbar Interbody Fusion Using rhBMP-2 With Tapered Interbody Cages

TLDR

In a multicenter, prospective, randomized 2‑year trial of 279 patients with degenerative lumbar disc disease, investigators compared two tapered threaded fusion cages, with one group receiving rhBMP‑2 on an absorbable collagen sponge and the other receiving autogenous iliac crest bone graft, and assessed fusion by plain radiographs and CT at 6, 12, and 24 months. The rhBMP‑2 group had shorter operative time, less blood loss, a higher 24‑month fusion rate (94.5% vs 88.7%), and no graft‑harvest complications, while both groups showed similar pain and neurologic improvements, demonstrating that rhBMP‑2 with a tapered titanium cage achieves solid fusion without the need for iliac crest bone harvest.

Abstract

In a multicenter, prospective, randomized, nonblinded, 2-year study, 279 patients with degenerative lumbar disc disease were randomly divided into two groups that underwent interbody fusion using two tapered threaded fusion cages. The investigational group (143 patients) received rhBMP-2 on an absorbable collagen sponge, and a control group (136 patients) received autogenous iliac crest bone graft. Plain radiographs and computed tomographic scans were used to evaluate fusion at 6, 12, and 24 months after surgery. Mean operative time (1.6 hours) and blood loss (109.8 mL) were less in the investigational rhBMP-2 group than in the autograft control group (2.0 hours and 153.1 mL). At 24 months the investigational group's fusion rate (94.5%) remained higher than that of the control group (88.7%). New bone formation occurred in all investigational patients. At all intervals, mean postoperative Oswestry, back pain, and leg pain scores and neurologic status improved in both treatment groups with similar outcomes. In the control group, eight adverse events related to the iliac crest graft harvest occurred (5.9%), and at 24 months 32% of patients reported graft site discomfort and 16% were bothered by its appearance. Lumbar fusion using rhBMP-2 and a tapered titanium fusion cage can yield a solid union and eliminate the need for harvesting iliac crest bone graft.