Comparing two lumbar radiofrequency ablation approaches for chronic low back pain

ASTRAL: A Superiority Trial of Radiofrequency Ablation for Low Back Pain

This trial will test whether two types of lumbar radiofrequency ablation help adults with chronic low back pain feel and move better than a simulated procedure.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 300 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: University of Washington (Academic / other)
• Drugs / interventions: radiation
• Locations: 3 sites (Atlanta, Georgia and 2 other locations)
• Trial ID: NCT07222462 on ClinicalTrials.gov

What this trial studies

This multicenter, double-blind randomized trial enrolls adults with chronic low back pain who had strong short-term relief from diagnostic medial branch nerve blocks and randomizes them to one of three groups: conventional parallel-electrode LRFA, multi-tined perpendicular-electrode LRFA, or a simulated procedure. Procedures follow standard LRFA techniques with verification by nerve stimulation for the conventional approach and a larger-lesion multi-tined electrode for the alternate approach. The primary outcome compares improvement in back-related functional limitations between each active LRFA technique and the simulated control. Secondary analyses will compare procedure duration, radiation exposure, and pain intensity between the two active LRFA methods.

Who should consider this trial

Good fit: Adults (≥18) with chronic low back pain of at least 3 months' duration who have tried conservative treatments and had ≥80% pain relief from two anesthetic-only medial branch blocks are ideal candidates.

Not a fit: Patients whose pain is not likely facet-mediated (no substantial relief from diagnostic medial branch blocks), those with low baseline pain intensity (NRS <4), or those who are anatomically ineligible for the LRFA procedures may not receive benefit from participating.

Why it matters

Potential benefit: If successful, the results could identify a more effective LRFA technique that provides better and longer-lasting pain relief and improved function for people with facet-mediated chronic low back pain.

How similar studies have performed: Lumbar radiofrequency ablation is commonly used and prior non-blinded studies suggest benefit, but a definitive double-blind, multicenter randomized comparison against a simulated procedure has not yet been completed.

Eligibility criteria

Inclusion Criteria:

* Age ≥18 years
* CLBP of duration ≥ 3 months. Low back pain is defined as occurring between the lower posterior margin of the rib cage and the horizontal gluteal fold.
* Low back pain intensity numerical rating scale (NRS) ≥ 4 with one of the following prior to LRFA: 1) Current low back pain intensity, 2) Average pain over past 7 days, OR 3) Pain intensity without specification of recall period
* Has had conservative treatments for CLBP (physical therapy, exercise therapy, spinal manipulation, massage, acupuncture, etc.)
* Candidate for unilateral LRFA (L1-S1 joints; ≤3 levels); or bilateral LRFA (L1-S1 joints; ≤2 levels)
* 'Positive responses' (≥80% improvement of CLBP pain intensity) to 2 sets of anesthetic-only MBBs (≤0.5cc of local anesthetic)
* Able to read, speak, and understand English sufficient for informed consent purposes
* Stated willingness to comply with all study processes and availability for the duration of the study, and provision of a signed and dated informed consent form

Exclusion Criteria:

* CLBP attributed primarily to specific spine-related conditions (radiculopathy, lumbar spinal stenosis, spinal instability), 'red flag' conditions (infection / malignancy / fracture), and/or inflammatory arthritis (RA, SpA, etc.)
* Prior LRFA
* Prior lumbar facet joint (intra-articular or medial branch nerve) corticosteroid injections (past 6 months)
* Surgery involving one or more of spinal levels where LRFA is to be performed, in the past 2 years
* Lumbar fusion involving the spinal levels where LRFA is considered, at any time
* Prior known severe lumbar central canal stenosis on MRI as defined by Lee (2011): obliteration of the cerebrospinal fluid (CSF), and marked compression of dural sac, and none of the cauda equina can be visually separated from each other. No new MRIs would be done specifically as part of the study processes.
* Prior formal diagnosis of fibromyalgia by a rheumatologist (diagnosis by primary care physician or pain medicine specialist is not sufficient)
* Unstable psychiatric or terminal medical conditions that would limit study participation and the likelihood of follow-up for 12 months post-randomization
* Pregnancy, being a prisoner, or having a prior formal diagnosis of cognitive impairment by a neuropsychologist or neurologist, confirmed by health record documentation
* Participant report of prior formal diagnosis of cognitive impairment by a neuropsychologist or neurologist can be obtained, but participant-reported cognitive impairment by a neuropsychologist or neurologist must be confirmed via health record documentation. No new evaluations for cognitive impairment would be done specifically as part of the study processes.
* Contraindication to local anesthetic, corticosteroid, or any aspects of LRFA
* Cannot reach MBB targets with 11.9cm needle
* Major planned life events over the next 4 months that might interfere with study participation (e.g., major abdominal or chest surgery or extended vacation)

Where this trial is running

Atlanta, Georgia and 2 other locations

• Emory Musculoskeletal Institute — Atlanta, Georgia, United States (Recruiting)
• Cleveland Clinic — Cleveland, Ohio, United States (Recruiting)
• University of Utah Orthopaedic Center/PM&R — Salt Lake City, Utah, United States (Not_yet_recruiting)

Study contacts

• Principal investigator: Pradeep Suri, MD — University of Washington
• Study coordinator: Research Study Coordinator

Conditions Chronic Low Back Pain; lumbar radiofrequency ablation; corticosteroid injections