Abstract
Summary
In this study, OsteoAMP® bone graft showed superior fusion rates as compared to rhBMP-2 at all timepoints (p<0.004). Additionally, OsteoAMP® bone graft had >80% few adverse events as compared to rhBMP-2.
Introduction
Adverse events and complications related to use of rhBMP-2 have raised many ethical, legal, and reimbursement concerns for surgeons. OsteoAMP® bone graft is an allograft derived growth factor, rich in osteoinductive, angiogenic, and mitogenic proteins. The following data displays a blinded, multi -center study evaluating and comparing fusion outcomes between rhBMP-2 and OsteoAMP® bone graft.
Patients & Methods
A total of 254 consecutive patients (383 total levels) were treated with TLIF or LLIF spine fusion procedures. A group of 70 patients (53.3 ± 11.1 y/o) were treated with rhBMP-2 (Infuse®/Inductos®, Medtronic) and local bone inside of a PEEK interbody cage with an average of 1.44 levels per surgery. A group of 184 patients (60.5 ± 13.1 y/o) were treated with OsteoAMP® (Advanced Biologics) and local bone inside of a PEEK interbody cage with an average of 1.53 levels per surgery. Fusion assessments were made by a blinded independent radiologist based on radiograph and CT images at 6w, 3m, 6m, 12m, and 18m follow up. Radiographically evident adverse events were also assessed in a blinded manner by an independent radiologist.
Results
Overall fusion analysis showed superiority in efficacy of OsteoAMP® over rhBMP-2 at all time points (p<0.004). Use of rhBMP-2 produced limited early fusions at 6 months (22.7%) yet improved at 1 year (71.4%). OsteoAMP® facilitated fusion for the majority of patients by 6 months (54.1%) and nearly all patients within 1 year (93.9%). At 18 months, 99.3% of OsteoAMP® patients had fused while the rhBMP-2 arm had an 86.7% fusion rate. Total time for fusion for OsteoAMP® was approximately half that of rhBMP-2 at 211.4 days and 407.1 days respectively. A subset cohort of 47 patients in the rhBMP-2 arm had OsteoAMP® packed anterior to the PEEK cage. When OsteoAMP® was used as an extender to rhBMP-2 in this manner, fusion rates increased at all timepoints (p=0.05 at 18 months) over patients that only had rhBMP-2 and local bone within the disc space. Though, the fusion rates of OsteoAMP® without rhBMP-2 remained higher than the rhBMP-2/local bone/OsteoAMP® extender cohort at all timepoints (p<0.05). To further isolate the effect of OsteoAMP, a subset cohort of 52 patients within the OsteoAMP® treatment arm in the absence of rhBMP-2 did not utilise bone marrow aspirate. The fusion rates of patients within this cohort was statistically higher at 6 months but did not show statistically higher fusion rates at 3 months, 12 months, or 18 months (p>0.12). When compared to the rhBMP-2 study arm, patients within the OsteoAMP® arm that did not receive bone marrow aspirate demonstrated higher fusion rates at all time points (p<0.04 at 12 and 18 months). The rhBMP-2 arm had more than 5 times the incidence of radiologically evident adverse events (osteolysis and ectopic bone formation) compared to the OsteoAMP® arm (43.3% vs. 8.2%, respectively).
Discussion
Despite its use with an older patient population and a higher number of levels per surgery, OsteoAMP® has shown great promise as a faster and safer alternative to rhBMP-2 in lumbar spine surgery.
