Effect of Radiofrequency Denervation on Pain Intensity Among Patients With Chronic Low Back Pain: The Mint Randomized Clinical Trials

Abstract

Importance: Radiofrequency denervation is a commonly used treatment for chronic low back pain, but high-quality evidence for its effectiveness is lacking.

Objective: To evaluate the effectiveness of radiofrequency denervation added to a standardized exercise program for patients with chronic low back pain.

Design, setting, and participants: Three pragmatic multicenter, nonblinded randomized clinical trials on the effectiveness of minimal interventional treatments for participants with chronic low back pain (Mint study) were conducted in 16 multidisciplinary pain clinics in the Netherlands. Eligible participants were included between January 1, 2013, and October 24, 2014, and had chronic low back pain, a positive diagnostic block at the facet joints (facet joint trial, 251 participants), sacroiliac joints (sacroiliac joint trial, 228 participants), or a combination of facet joints, sacroiliac joints, or intervertebral disks (combination trial, 202 participants) and were unresponsive to conservative care.

Interventions: All participants received a 3-month standardized exercise program and psychological support if needed. Participants in the intervention group received radiofrequency denervation as well. This is usually a 1-time procedure, but the maximum number of treatments in the trial was 3.

Main outcomes and measures: The primary outcome was pain intensity (numeric rating scale, 0-10; whereby 0 indicated no pain and 10 indicated worst pain imaginable) measured 3 months after the intervention. The prespecified minimal clinically important difference was defined as 2 points or more. Final follow-up was at 12 months, ending October 2015.

Results: Among 681 participants who were randomized (mean age, 52.2 years; 421 women [61.8%], mean baseline pain intensity, 7.1), 599 (88%) completed the 3-month follow-up, and 521 (77%) completed the 12-month follow-up. The mean difference in pain intensity between the radiofrequency denervation and control groups at 3 months was -0.18 (95% CI, -0.76 to 0.40) in the facet joint trial; -0.71 (95% CI, -1.35 to -0.06) in the sacroiliac joint trial; and -0.99 (95% CI, -1.73 to -0.25) in the combination trial.

Conclusions and relevance: In 3 randomized clinical trials of participants with chronic low back pain originating in the facet joints, sacroiliac joints, or a combination of facet joints, sacroiliac joints, or intervertebral disks, radiofrequency denervation combined with a standardized exercise program resulted in either no improvement or no clinically important improvement in chronic low back pain compared with a standardized exercise program alone. The findings do not support the use of radiofrequency denervation to treat chronic low back pain from these sources.

Trial registration: trialregister.nl Identifier: NTR3531.

Figure 1.. Flow of Patients Through Enrollment in the 3 Randomized Clinical Trials

BMI indicates body mass index (calculated as weight in kilograms divided by height in meters squared). ^aObservational study was performed alongside randomized clinical trials; results from the observational study are not reported in this article. ^bParticipants not eligible for participation due to 1 positive exclusion criterion or more could be included in the observational study. ^cParticipants were excluded based on psychological problems, assessed by validated questionnaires.

Figure 2.. Flow of Patients Through the Facet Joint and Sacroiliac Joint Trials

^aParticipants received RF treatment other than their randomized assignment. ^bStudy withdrawals were not cumulative.

Figure 3.. Flow of Patients Through the Combination Trial