Comparative cost effectiveness of Coflex® interlaminar stabilization versus instrumented posterolateral lumbar fusion for the treatment of lumbar spinal stenosis and spondylolisthesis

Abstract

Jordana Kate Schmier,1 Marci Halevi,2 Greg Maislin,3 Kevin Ong4 1Health Sciences, Exponent Inc., Alexandria, VA, USA; 2Paradigm LLC, New York, NY, USA; 3Biomedical Statistical Consulting, Wynnewood, PA, USA; 4Biomedical Engineering, Exponent Inc., Philadelphia, PA, USA Introduction: Symptomatic chronic low back and leg pain resulting from lumbar spinal stenosis is expensive to treat and manage. A randomized, controlled, multicenter US Food and Drug Administration Investigational Device Exemption clinical trial assessed treatment-related patient outcomes comparing the Coflex® Interlaminar Stabilization Device, an interlaminar stabilization implant inserted following decompressive surgical laminotomy in the lumbar spine, to instrumented posterolateral fusion among patients with moderate to severe spinal stenosis. This study uses patient-reported outcomes and clinical events from the trial along with costs and expected resource utilization to determine cost effectiveness. Methods: A decision-analytic model compared outcomes over 5 years. Clinical input parameters were derived from the trial. Oswestry Disability Index scores were converted to utilities. Treatment patterns over 5 years were estimated based on claims analyses and expert opinion. A third-party payer perspective was used; costs (in $US 2013) and outcomes were discounted at 3% annually. Sensitivity analyses examined the influence of key parameters. Analyses were conducted using Medicare payment rates and typical commercial reimbursements. Results: Five-year costs were lower for patients implanted with Coflex compared to those undergoing fusion. Average Medicare payments over 5 years were estimated at $15,182 for Coflex compared to $26,863 for the fusion control, a difference of $11,681. Mean quality-adjusted life years were higher for Coflex patients compared to controls (3.02 vs 2.97). Results indicate that patients implanted with the Coflex device derive more utility, on average, than those treated with fusion, but at substantially lower costs. The cost advantage was greater when evaluating commercial insurance payments. Subgroup analyses found that the cost advantage for Coflex relative to fusion was even larger for two-level procedures compared to one-level procedures. Conclusion: The Coflex Interlaminar Stabilization Device was found to be cost effective compared to instrumented posterolateral fusion for treatment of lumbar spinal stenosis. It provided higher utility at substantially lower cost. Keywords: cost analysis, spine, treatment comparison