Clinical Outcomes and Fusion Success at Two Years of Single Level Instrumented Posterolateral Fusions with rhBMP2/CRM** vs. Iliac Crest Bone Graft

Summary: In a prospective, randomized study comparing ICBG to BMP/CRM in instrumented posterolateral fusions for single-level degenerative disc disease using a higher rhBMP2 dose and a carrier specific for posterior spine applications, there was significant improvement of SF-36, ODI, leg and back pain scores in both groups over all time intervals. Surgical time and blood loss was significantly less in the BMP/CRM group. The fusion rate in the BMP/CRM group was similar to the ICBG group.

Purpose: RhBMP2 with a collagen carrier has shown similar clinical outcomes and fusion rates as iliac crest bone graft (ICBG) in anterior instrumented interbody fusions. As part of an FDA-regulated IDE study, we evaluated clinical outcomes and fusion rates on 24 month CT scans of single-level instrumented posterolateral fusions using ICBG or BMP/CRM.

Methods: This is a prospective, randomized study comparing ICBG to BMP/CRM in instrumented posterolateral fusions for single-level degenerative disc disease (DDD). A rhBMP2 dose (2.0mg/cc) and a carrier specific for posterior spine applications was used. Demographic and perioperative data, SF-36, Oswestry Disability Index (ODI), leg and back pain scores were determined pre-operatively, and 6 weeks, 3, 6, 12, and 24 months post-operatively. Independent neuroradiologists' evaluation of fine-cut CT scans with sagittal and coronal reconstructions were obtained at 6, 12, and 24 months.

Results: Of 141 patients enrolled, 57 (30 ICBG, 27 BMP/CRM) reached 2-year follow-up. There were no significant differences for age, weight, sex, smoking, or previous surgery between the groups. The average operative time (2.6hrs), blood loss (393cc) and hospital stay (4.0 days) in the ICBG group was statistically significantly greater (p<0 .001) than in the BMP/CRM group (2.2hrs, 270cc, 3.8days). There were no statistically significant differences any outcome measure at all time intervals to 2 years. was a trend but difference (p="0.20)" fusion rates between two groups, with 25/30 solid fusions ICBG and 26/27 based on 24 month CT scans.

Conclusion: There was significant improvement of SF-36 (PCS), ODI, leg and back pain scores in both groups over all time intervals. Surgical time and blood loss was significantly less in the BMP/CRM groups. The fusion rate in the BMP/CRM group was similar to the ICBG group.

FDA Disclosure Cleared: No ** BMP/CRM