Use of bone morphogenetic proteins in spinal fusion surgery for older adults with lumbar stenosis: Trends, complications, repeat surgery, and charges

Study Design.: Retrospective cohort study of Medicare claims. Objective.: Examine trends and patterns in the use of bone morphogenetic proteins (BMP) in surgery for lumbar stenosis; compare complications, reoperation rates, and charges for patients undergoing lumbar fusion with and without BMP. Summary of Background Data.: Small, randomized trials have demonstrated higher rates of solid fusion with BMP than with allograft bone alone, with few complications and, in some studies, reduced rates of revision surgery. However, complication and reoperation rates from large population-based cohorts in routine care are unavailable. Methods.: We identified patients with a primary diagnosis of lumbar stenosis who had fusion surgery in 2003 or 2004 (n = 16,822). We identified factors associated with BMP use: major medical complications during the index hospitalization, rates of rehospitalization within 30 days, and rates of reoperation within 4 years of follow-up (through 2008). Results.: Use of BMP increased rapidly, from 5.5% of fusion cases in 2003 to 28.1% of fusion cases in 2008. BMP use was greater among patients with previous surgery and among those having complex fusion procedures (combined anterior and posterior approach, or greater than 2 disc levels). Major medical complications, wound complications, and 30-day rehospitalization rates were nearly identical with or without BMP. Reoperation rates were also very similar, even after stratifying by previous surgery or surgical complexity, and after adjusting for demographic and clinical features. On average, adjusted hospital charges for operations involving BMP were about $15,000 more than hospital charges for fusions without BMP, though reimbursement under Medicare's Diagnosis-Related Group system averaged only about $850 more. Significantly fewer patients receiving BMP were discharged to a skilled nursing facility (15.9% vs. 19.0%, P < 0.001). Conclusion.: In this older population having fusion surgery for lumbar stenosis, uptake of BMP was rapid, and greatest among patients with prior surgery or having complex fusion procedures. BMP appeared safe in the perioperative period, with no increase in major medical complications. Use of BMP was associated with greater hospital charges but fewer nursing home discharges, and was not associated with reduced likelihood of reoperation.