The Influence of Geography, Time, and Payer Type on the Utilization of Bone Morphogenetic Protein (BMP) Between 2005 and 2015

Decline in Separate Incision Autograft for Spine Surgery Over the Past Decade: A Fading "gold standard"

BACKGROUND

Spinal fusion is a common procedure for which bone grafting is a critical component. Although iliac crest (separate incision autograft) is typically referred to as the "gold standard" grafting material, it seems to be used less and less frequently.

METHODS

The 2010 to Q3 2020 MSpine PearlDiver data set was used to identify patients receiving separate incision autograft versus local autograft/allograft/graft supplement for spinal fusion. Grafting trends over the decade were determined. Patient age, sex, Elixhauser Comorbidity Index, smoking status, insurance plan, region of the country where the surgery was conducted, and surgeon specialty were characterized and compared by the type of bone graft using univariate and multivariate analyses.

RESULTS

Of 373,569 spinal bone grafting procedures, separate incision autografts were used for 32,401 (8.67%). A gradual decline was observed from 2010 (10.57% of spinal grafting procedures) to 2020 (4.69%, P -value < 0.00001). Independent predictors of having had a separate incision autograft in order of decreasing odds included surgeon specialty (relative to neurosurgery, orthopaedic odds ratio [OR], 2.45), smoking status (relative to nonsmokers, smokers OR, 1.45), region of the country (relative to Midwest, Northeast OR, 1.11; West OR, 1.42; and South OR, 1.48), insurance (relative to commercial, Medicare OR, 1.14), younger age (OR, 1.04 per decade increase), and lower Elixhauser Comorbidity Index (OR, 0.95 per two-point increase) ( P < 0.0001 for each).

CONCLUSION

Iliac crest autograft continues to be referred to as the gold standard grafting material for spine fusions. However, the use of this has faded over the past decade to only 4.69% of spinal fusions in 2020. While some patient factors had an effect on when separate incision autograft was used, nonsurgical factors, including surgeon specialty, geographic region where the surgery was conducted, and insurance factors, suggested that external factors/physician training influence this choice.

Current Trends in Recombinant Human Bone Morphogenetic Protein 2 (rhBMP2) Usage for Spinal Fusion Surgery

(1) Background: Since first approved by the FDA, on-label and off-label usage of recombinant human bone morphogenetic protein 2 (rhBMP2) for spinal fusion surgeries has become widespread. While many studies have investigated the safety and efficacy of its use, as well as its economic impact, few have looked at the current trends in its on- and off-label use. The goal of this study is to evaluate the current trends of on- and off-label rhBMP2 use for spinal fusion surgery. (2) Methods: A deidentified survey was created and electronically distributed to members of two international spine societies. Surgeons were asked to report their demographic information, surgical experience, and current usage of rhBMP2. They were then presented with five spinal fusion procedures and asked to report if they use rhBMP2 for these indications in their current practice. Responses were stratified between rhBMP2 users vs. non-users and on-label vs. off-label use. Data were analyzed using chi-square with Fisher's exact test for categorical data. (3) Results: A total of 146 respondents completed the survey with a response rate of 20.5%. There was no difference in overall rhBMP2 usage based on specialty, experience, or number of cases per year. Fellowship-trained surgeons and those who practice in the United States were more likely to use rhBMP2. Surgeons who were trained in the Southeast and Midwest regions reported the highest usage rates. rhBMP2 use was more common among fellowship-trained and US surgeons for ALIFs; non-US surgeons for multilevel anterior cervical discectomy and fusions; and fellowship-trained and orthopedic spine surgeons for lateral lumbar interbody fusions. Non-US surgeons were more likely to use rhBMP2 for off-label indications compared to surgeons from the US. (4) Conclusions: While various demographics of surgeons report different rates of rhBMP2 use, off-label use remains relatively commonplace amongst practicing spine surgeons.

Trends, payments, and costs associated with BMP use in Medicare beneficiaries undergoing spinal fusion

BACKGROUND CONTEXT

Bone morphogenic protein (BMP) promotes bony fusion but increases costs. Recent trends in BMP use among Medicare patients have not been well-characterized.

PURPOSE

To assess utilization trends, complication, payments, and costs associated with BMP use in spinal fusion in a Medicare-insured population.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Total of 316,070 patients who underwent spinal fusion in a 20% sample of Medicare-insured patients, 2006 to 2015.

OUTCOME MEASURES

Utilization trends across time and geography, complications, payments, and costs.

METHODS

Patients were stratified by fusion type and diagnosis. Multivariable logistic and linear regression were used to adjust for the effect of baseline characteristics on complications and total payments or cost, respectively.

RESULTS

BMP was used in 60,249 cases (19.1%). BMP utilization rates decreased from 23.1% in 2006 to 12.0% in 2015, most significantly in anterior cervical (7.5%-3.1%), posterior cervical (17.0%-8.3%), and posterior lumbar fusions (31.5%-15.8%). There are significant state- and region-level geographic differences in BMP utilization. Across all years, states with the highest BMP use were Indiana (28.5%), Colorado (26.6%), and Nevada (25.7%). States with the lowest BMP use were Maine (2.3%), Vermont (8.2%), and Mississippi (10.4%). After multivariate risk adjustment, BMP use was associated with decreased overall complications in thoracic (odds ratios [OR] [95% confidence intervals [CI]): 0.89 [0.81-0.99]) and anterior lumbar fusions (OR [95% CI]: 0.89 [0.84-0.95]), as well as increased reoperation rates in anterior cervical (OR [95% CI]: 1.11 [1.04-1.19]), posterior cervical (OR (95% CI): 1.14 (1.04-1.25)), thoracic (OR (95% CI): 1.32 (1.23-1.41)), and posterior lumbar fusions (OR (95% CI): 1.11 (1.06-1.16)). BMP use was also associated with greater total costs, independent of fusion type, after multivariate risk adjustment (p<.0001). Payments, however, were comparable between groups in anterior and posterior cervical fusion with or without BMP. BMP use was associated with greater total payments in thoracic, anterior lumbar, and posterior lumbar fusions. Notably, the difference in payments was smaller than the associated cost increase in all fusion types.

CONCLUSIONS

BMP use has declined across all fusion types over the last decade, after a peak in 2007. While BMP is associated with greater costs, reimbursement does not increase proportionally with BMP cost.

Utilization Trends of Recombinant Human Bone Morphogenetic Protein in the United States

STUDY DESIGN

Retrospective.

OBJECTIVE

The aim of this study was to explore the utilization trends of recombinant human bone morphogenetic protein (rh-BMP) in the United States using the largest inpatient administrative database.

SUMMARY OF BACKGROUND DATA

Since 2002, the rh-BMP has been widely used by the surgical spine community in fusion surgery. In light of the rising evidence regarding the safety and efficacy of this novel and expensive bone biological technology, a comprehensive examination of its utilization in the American population is warranted.

METHODS

We queried the 2002-Q3 2015 National Inpatient Sample for patients that underwent spinal fusion with rh-BMP. We calculated population-level estimates of rh-BMP utilization trends per 100,000 spinal fusions. Trends were estimated for the overall use as well as broken down by primary versus revision fusion, fusion type, number of levels, age category, US region, and hospital type.

RESULTS

A total of 5,563,282 fusions were performed, of which 19.9% (n = 1,108,984) utilized rh-BMP. We detected an increase in rh-BMP use in spinal fusion surgery from 0.7% in 2002 to a peak of 29.5% in 2010, followed by a gradual decline till Q3 2015, where it represented 14.7% of all fusion surgeries. These trends paralleled all fusion types. It was most commonly used in fusions spanning two to three levels. The South remained the most common region, whereas West has recently surpassed the Midwest. Its use is becoming more pervasive among older patients, particularly in the 65- to 74 years' age group.

CONCLUSION

Further studies are needed to provide insights into the correlation of these trends with the technology's safety and efficacy profile in contemporary series.Level of Evidence: 3.

New Strategies in Enhancing Spinal Fusion

The biologic steps involved in creating a bony fusion between adjacent segments of the spine are a complex and highly coordinated series of events. There have been significant advancements in bone grafts and bone graft substitutes in order to augment spinal fusion. While autologous bone grafting remains the gold standard, allograft bone grafting, synthetic bone graft substitutes, and bone graft enhancers are appropriate in certain clinical situations. This article provides an overview of the basic biology of spinal fusion and strategies for enhancing fusion through innovations in bone graft material.