Introduction: Bone morphogenetic protein (BMP) was approved by the US Food and Drug Administration in 2002 for use in lumbar fusion surgery. Though it is thought to increase the likelihood of bone fusion and thus reduce reoperation rates, studies have yielded conflicting data. Additionally, recent studies have questioned the safety profile of BMP, noting trial design biases. The goal of this study was to 1) examine the two-year reoperation and complication rates; and 2) quantify the healthcare resource use for patients who underwent spinal lumbar fusion for degenerative conditions with and without BMP.
Methods: Reuter’s MarketScan database was utilized to identify 35,400 patients who underwent spinal fusion for degenerative lumbar disease between 2002 and 2009. Propensity score matching (PSM) techniques were used to match 4,310 patients who underwent spinal fusion with BMP to those who underwent spinal fusion without BMP.
Results: The use of BMP was associated with a reduced risk of reoperation at 1 (p=0.0010) and 2 years (OR:0.814, 95 %CI:0.696–0.952, p=0.0101) following the index procedure. Additionally BMP was not seen to be significantly associated with the occurrence of postoperative complications. Patients who received BMP had significantly higher index hospitalization charges ($55,090 vs. $48,590, p<0.0001) though the lengths of stay were comparable. This trend continued, with those in the BMP group having higher hospital charges over 2 years (p=0.0206), despite having fewer hospital days (p=0.0109). However the accumulated outpatient charges over 2 years were significantly lower in those who received BMP (p=0.01). This led the BMP group to have significantly lower inpatient and outpatient charges 2 years following the index procedure ($27,789 vs. $28,476, p=0.02).
Conclusions: Although BMP was associated with higher cost during the index hospitalization, two years following lumbar fusion, BMP was associated with lower reoperation rates, fewer hospital days, and less inpatient and outpatient charges.
Patient Care: Despite approval nearly 10 years ago, the efficacy of BMP in reducing reoperation rates following lumbar fusion surgery is still unclear. The use of BMP quickly became routine, especially in patients who were osteopenic and those thought to have a reduced osteoinductive capacity. This frequent use in patients with differing characteristics from those included in trials, and the frequent off-label use may be the cause of conflicting data. In our cohort of nationally selected patients, we show BMP to reduce the risk of reoperation up to 2 years following the initial procedure. Due to the uncertain efficacy in reducing reoperation risk, the cost-effectiveness of BMP has been questioned. We show that though BMP use resulted in significantly higher hospital costs for the index procedure, total 2 year inpatient and outpatient costs were decreased. Also, there has been increasing concern regarding the safety of BMP, with a recent study reporting the risk of adverse events with the use of BMP to be 10 to 50 times greater than those reported in industry-sponsored studies. However, we report that BMP is not associated with increased postoperative complication following lumbar fusion surgery for degenerative conditions. As this study demonstrates the safety of BMP for use in lumbar fusion surgery, we recommend the selective use of BMP to improve the likelihood of bony fusion.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of understanding the pros and cons of BMP use in lumbar fusion surgery, 2) Discuss, in small groups the efficacy of BMP in reducing reoperation risk with comparable complication rates and decreased long-term cost, 3) Identify an effective treatment for degenerative spine conditions which reduces the reoperation rates and long-term costs following spinal fusion.