Recombinant Bone Morphogenetic Protein Linked to Reduce Risk of Reoperation Following Spine Fusion for Adult Scoliosis
Comments by Baron S. Lonner, MD and Eeric Truumees, MD
Use of bone morphogenetic protein-2 (BMP) in spinal fusions for adult scoliosis was associated with a significantly reduced risk for reoperation for pseudoarthrosis in a retrospective review of an administrative database published in Spine. The greatest beneficial effect of BMP was found for longer fusion lengths (ie, >8 levels).
“Our research shows that BMP should be considered for all spinal deformity cases in adults, especially for those involving longer fusions,” said co-author Baron S. Lonner, MD, Chief of the Division of Spine Surgery and Professor of Orthopaedic Surgery at Mount Sinai, New York, NY.
The study authors reviewed data from the 2008-2011 New York State Inpatient Sample Database and identified 3,751 patients (aged ≥21 years) with scoliosis who underwent multilevel spinal arthrodesis in 2008. BMP was used in 37.6% of procedures.
One-Quarter of Longer Fusions Required Reoperation
During the 4-year follow-up period, the overall rate of reoperation for pseudoarthrosis was 4.4% for short fusions (≤8 levels) and 23.4% for longer fusions (>8 levels). The use of BMP at the index surgery was associated with a significantly lower risk for reoperation in longer fusions (5%) vs 34% without use of BMP (relative risk [RR], 7.5; P<0.001). The beneficial effect of BMP on the reoperation rate was less marked among short fusions (1% vs 6%; RR, 4.1).
The findings illustrate the potential for at least one level not to fuse in nearly one in four patients undergoing longer fusions, Dr. Lonner explained. This lack of fusion “can result in rod breakage, recurrence of deformity, pain, and the need for reoperation,” he explained. Reoperation “exposes patients to additional risks, such as infection, anesthetic complications, and other medical complications following the procedure.”
Cost of Care and Reimbursement Considerations
“The upfront costs in caring for patients with spinal deformity, especially adults, are very high,” Dr. Lonner explained. “However, improvements in outcome scores are high as well. When you allow [the benefits of spinal fusion] to accrue over time, fusion becomes a cost-effective operation with durable results. The exception is patients who require reoperation; for these patients, the procedure is not cost-effective.”
Dr. Lonner called for a thorough cost analysis of the use of BMP in this patient population. He believes that the additional cost of using BMP would be at least partially offset by lower reoperation rates, if examined from a societal perspective.
“The FDA’s indication for the use of BMP is not aligned with the use in adult spinal deformity. It is indicated for use in one-level lumbar spinal fusion done from an anterior approach with a specific cage type,” Dr. Lonner explained. “Thus, use of BMP for adult spinal deformity is almost always “off-label,” and insurance companies often use that as an excuse not to cover the cost of this biologic tool. This is really short-sighted given the fact that reoperation rates are so high down the line without the use of BMP,” he added.
Dr. Lonner said it is incumbent upon surgeons and researchers to provide clinical data for use of BMP in fusion surgery not only from large administrative databases, but also from single center studies. “We need to do longer-term outcome studies with cost efficacy analysis, and then go back to insurance companies and show them that this is really an important tool in our armamentarium in the treatment of adult spinal deformity patients.”
Eeric Truumees, MD
CEO, Seton Brain & Spine Institute, Seton Spine and Scoliosis Center
Brackenridge University Hospital & Seton Medical Center
Administration and Development Council Director
North American Spine Society
I congratulate Dr. Lonner and his co-authors on this study. Often, a single surgeon or single center’s experience is inadequate to clearly identify the relative risks and benefits of expensive surgical interventions.
Multilevel spine fusions, in particular, benefit from this type of high-altitude assessment. That said, the limitations of this type of database analysis also must be recognized. The authors acknowledge these limitations. To my mind, the most important limitation is the ability of these databases to fully capture the events in question. For example, cases may be missed due to coding issues or when patients seek care outside the geographic area or time frame encompassed by the study.
This study, and others that have preceded it, suggest that use of BMP is most justifiable in patients at high risk for pseudoarthrosis. This includes revision surgeries, but also multilevel deformity procedures.
Dr. Lonner is correct that current FDA labeling is not in line with the current literature and most spine surgeons’ opinions regarding BMP. Single-level anterior lumbar fusions have high fusion rates without BMP. The “off-label” status of BMP in complex, posterolateral fusion procedures challenges educators and manufacturers in discussing the best carriers for BMP as well as other tips and pearls to ensure safer use and optimized risk/benefit algorithms. This study does not identify potential downsides of BMP use, nor does it inform the reader of the best ways to use BMP in these higher risk patients.