A prospective study of lumbar facet arthroplasty in the treatment of degenerative spondylolisthesis and stenosis: cost-effective assessment from the Total Posterior Spine system (TOPS TM ) IDE Study: 2-year model revision and sensitivity analyses based on 305 subjects

BACKGROUND CONTEXT: A previous cost-effectiveness analysis published in 2022 found that the Total Posterior Spine (TOPS TM ) system was dominant over transforaminal lumbar interbody fusion (TLIF). This analysis required updating to reflect a more complete dataset and pricing considerations. PURPOSE: To evaluate the cost-effectiveness of TOPS TM system as compared with TLIF based on an updated and complete FDA investigational device exemption (IDE) data set. STUDY DESIGN/SETTING: Cost-utility analysis of the TOPS TM system compared to TLIF. PATIENT SAMPLE: A multicenter, FDA IDE, randomized control trial (RCT) investigated the efficacy of TOPS TM compared to TLIF with a current population of n=305 enrolled and n=168 with complete 2-year follow-up. OUTCOME MEASURES: Cost and quality adjusted life years (QALYs) were calculated to determine our primary outcome measure, the incremental cost-effectiveness ratio. Secondary outcome measures included: net monetary benefit as well at willingness-to-pay (WTP) thresholds. METHODS: The primary outcome of cost-effectiveness is determined by incremental cost-effectiveness ratio. A Markov model was used to simulate the health outcomes and costs of patients undergoing TOPS TM or TLIF over a 2-year period. alternative scenario sensitivity analysis, oneway sensitivity analysis, and probabilistic sensitivity analysis were conducted to assess the robustness of the model results. RESULTS: The updated base case result demonstrated that TOPS TM was immediately and longitudinally dominant compared with the control with an incremental cost-effectiveness ratio of - 9,637.37 $/QALY. The net monetary benefit was correspondingly $2,237, both from the health system's perspective and at a WTP threshold of 50,000 $/QALY at the 2-year time point. This remained true in all scenarios tested. The Alternative Scenario Sensitivity Analysis suggested costeffectiveness irrespective of payer type and surgical setting. To remain cost-effective, the cost difference between TOPS TM and TLIF should be no greater than $1,875 and $3,750 at WTP thresholds of $50,000 and 100,000 $/QALY, respectively. CONCLUSIONS: This updated analysis confirms that the TOPS TM device is a cost-effective and economically dominant surgical treatment option for patients with lumbar stenosis and degenerative spondylolisthesis compared to TLIF in all scenarios examined. (c) 2024 The Authors. Published by Elsevier Inc