Accelerating Autograft Maturation in Instrumented Posterolateral Lumbar Spinal Fusions Without Donor Site Morbidity

Properly harvested iliac crest bone autograft applied to a meticulously prepared fusion bed produces a consistently high rate of fusion with a low incidence of donor site morbidity. Some reports advocate substituting bone morphogenic protein (BMP) for iliac crest bone autograft, but in posterolateral lumbar spinal fusion, BMP appears better suited to facilitate iliac crest bone autograft maturation than to substitute for it. In this single-center, nonrandomized, prospective study (minimum 2-year follow-up), cancellous-only iliac crest bone autograft was harvested for use in posterolateral lumbar spinal fusion. Reviewers blinded to graft condition and age assigned fusion scores to the random radiographs of 31 consecutive patients who underwent 1- to 3-level posterolateral lumbar spinal fusion using iliac crest bone autograft supplemented with either an implanted spinal fusion stimulator or BMP. There was no significant immediate or remote iliac crest bone autograft harvest morbidity, and there was a significant reduction in pain scores postoperatively ( P <.001). At 12 months, BMP radiographs were more likely than spinal fusion stimulator radiographs to be rated as fused ( P <.019). All BMP patients were deemed fused at 12 months and all spinal fusion stimulator patients at 24 months. In this study, iliac crest bone autograft supplemented with either BMP or spinal fusion stimulator resulted in a solid contiguous fusion without significant iliac crest bone autograft harvest-related morbidity. Bone morphogenic protein-supplemented iliac crest bone autograft fused at a faster rate, producing the more mature-appearing, trabeculated, robust fusion.