Interpreting the MINT Randomized Trials Evaluating Radiofrequency Ablation for Lumbar Facet and Sacroiliac Joint Pain: A Call From ASRA for Better Education, Study Design, and Performance

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Chronic low-back pain, with an annual prevalence ranging between 15% and 45%, is associated with significant health and socioeconomic costs that negatively affect individuals and our health care system.1 Low-back pain is the leading cause of occupational disability in the world and ranks fifth among conditions that lead individuals to seek medical attention.2 Furthermore, between 49% and 70% of all adults will experience an episode of low-back pain during their lifetime, whereas 12% to 30% of adults will have an active problem.3 In most cases, there is no clear etiology until proper diagnostic measures are used and interpreted.1,4 Although the proportions change with age, it has been estimated that approximately 40%, 30%, and 20% of adults experience low-back pain from either the disc, facet joint, or sacroiliac joint, respectively.4 National expenditures for spine conditions in the United States have increased on average 7% per year.5 Although a large proportion of this increase is related to inpatient care, prescription, surgical care, and emergency services, outpatient services including interventional therapies and physical therapy also have contributed to the unsustainable growth in health care costs.3,5 The surge in expenditures for spine treatments has not been accompanied by commensurate reductions in either the prevalence of back pain, spine operations, or disability rates,5,6 which has led to increased scrutiny by regulatory agencies and third-party payers.
One treatment that has been increasingly used for the treatment of axial spine pain originating from the lumbar facet and sacroiliac joints and to a lesser degree for discogenic pain is radiofrequency ablation (RFA). Recently, a pragmatic study (ie, the MINT randomized clinical trials) funded by the Netherlands Organization for Health Research and Development, the Dutch Society of Anesthesiology, and the Dutch Health Insurance Companies comparing a stand-alone 3-month standardized exercise program coupled with psychological support to the same program with the addition of RFA has raised important questions regarding the efficacy of RFA.7 The authors found that RFA combined with a standardized exercise program resulted in no clinically meaningful improvement in chronic low-back pain compared with the standardized exercise program alone. They concluded that the use of RFA is not supported in the treatment of chronic low-back pain and should be reserved for research purposes. The conclusions made by the authors are untenable not only because pragmatic studies should not be used to determine efficacy, but also because of the significant methodological issues in the study surrounding 3 major areas: (1) study design and data interpretation, (2) patient selection, and (3) RFA technique. The study suggests that there exist significant educational gaps in the interventional community regarding RFA and that studies with methodological issues may yield inauspicious results that can potentially negatively impact low-back care treatment.
The Juch et al7 study (MINT) did not use controlled diagnostic facet blocks. In determining the therapeutic efficacy of an interventional technique, it is critical to appropriately select patients with the indicated condition(s). Unlike comparative-effectiveness or pragmatic studies, which are designed to determine effectiveness under real-life circumstances, clinical trials that seek to determine “efficacy” should be rigorously designed, with strict selection criteria, screening many more patients than they enroll. This is not the case for pragmatic or comparative-effectiveness study, wherein the selection criteria are more liberal, to maximize generalization. For example, studies have shown that individuals with long durations of pain, who were enrolled in the MINT study (the median duration was approximately 10 years), are more likely to fail lumbar facet RFA.

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