A Superiority Trial of Radiofrequency Ablation for Low Back Pain

Purpose

The purpose of the ASTRAL Study is to evaluate the effectiveness of LRFA (Lumbar radiofrequency ablation) against a control procedure. The ASTRAL Study will enroll individuals with chronic low back pain (CLBP) and randomly assign them to one of three groups: lumbar radiofrequency ablation using conventional electrodes placed parallel to the medial branch nerves (LRFA-C), lumbar radiofrequency ablation using multi-tined electrodes placed perpendicular to the medial branch nerves (LRFA-M), or a simulated radiofrequency ablation procedure.

Condition

  • Chronic Low Back Pain (CLBP)

Eligibility

Eligible Ages
Over 18 Years
Eligible Sex
All
Accepts Healthy Volunteers
No

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)

Study Design

Phase
N/A
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Treatment
Masking
Triple (Participant, Investigator, Outcomes Assessor)

Arm Groups

ArmDescriptionAssigned Intervention
Active Comparator
LRFA-C 		Lumbar radiofrequency ablation with conventional electrodes
  • Procedure: Lumbar radiofrequency ablation with conventional electrodes (LRFA-C)
    LRFA-C positions a conventional thermal radiofrequency electrode at each medial branch nerve to be ablated and administers local anesthetic to the nerve. Parallel placement of the electrode will be achieved. Once the electrode is in correct position and nerve stimulation testing done, a radiofrequency lesion is generated, achieving a temperature 80°C-90°C, lasting 90-120 seconds. If a 16-gauge or larger electrode is used, no second lesion needs to be made. If an 18-gauge electrode is used, the electrode will be repositioned slightly by withdrawing or repositioning parallel to the 1st ablation site, or by rotating the electrode, and a 2nd lesion made. Local corticosteroid injection is then performed at the ablation site at a total corticosteroid equivalent of 80mg triamcinolone, divided equally among the medial branches targeted; this dose can be reduced as needed according to the medical status of each patient. This process is applied for each medial branch nerve targeted.
Active Comparator
LRFA-M 		Lumbar radiofrequency ablation with multi-tined electrodes
  • Procedure: Lumbar radiofrequency ablation with multi-tined electrodes (LRFA-M)
    LRFA-M positions a multi-tined thermal radiofrequency electrode at each medial branch nerve to be ablated and administers local anesthetic to the nerve. However, the multi-tined thermal radiofrequency electrode is thought to achieve larger lesions and thus does not require parallel electrode placement; the LRFA-M electrode will be placed perpendicular to the medial branch nerve. All subsequent processes are the same as for LRFA-C. This includes local corticosteroid injection at each ablation site at a total corticosteroid equivalent of 80mg triamcinolone, divided equally among the medial branches targeted; this dose can be reduced as needed according to the medical status of each patient. This process is applied for each medial branch nerve targeted.
Sham Comparator
Simulated LRFA 		Simulated lumbar radiofrequency ablation
  • Procedure: Simulated lumbar radiofrequency ablation
    The simulated LRFA control procedure will be performed in an identical fashion to LRFA-M, except 1) after electrode positioning, a neurodestructive lesion will not be made; and 2) a pre-recorded audio recording of the procedure will be played (out of view of the patient, immediately adjacent to the RFA machine) in order to simulate the beeping and other sounds of the machine and to ensure the appropriate length of the simulated procedure. The electrode will remain in place for the 90-120 seconds that lesioning would normally take, but without heat application. The electrode will then be repositioned to simulate a second lesion, also of duration 90-120 seconds. Local corticosteroid injection is then performed at the ablation site at a total corticosteroid equivalent of 80mg triamcinolone, divided equally among the medial branches targeted; this dose can be reduced as needed according to the medical status of each patient. This process is applied for each medial branch nerve targeted.

Recruiting Locations

Emory Musculoskeletal Institute
Atlanta 4180439, Georgia 4197000 30329
Contact:
Emory Orthopedics Clinical Research
404-778-8099
isabelle.m.vernon@emory.edu

Cleveland Clinic
Cleveland 5150529, Ohio 5165418 44195
Contact:
Nya Robinson
216-445-1741
ROBINSN8@ccf.org

More Details

Status
Recruiting
Sponsor
University of Washington

Study Contact

Research Study Coordinator
206-210-4040
astralstudy@uw.edu

Detailed Description

Low back pain is the #1 contributor to years lived with disability in the United States. Lumbar radiofrequency ablation (LRFA) is a minimally invasive procedure for chronic low back pain (CLBP) commonly used in the US, but the effectiveness of this procedure has yet to be fully explored, and a definitive, double-blind, multicenter RCT demonstrating a clinically relevant benefit of LRFA over a control procedure has yet to be conducted. LRFA-C involves placing a conventional radiofrequency electrode parallel to each targeted medial branch nerve, administering local anesthetic, and confirming placement with nerve stimulation as per standard clinical practice. LRFA-M follows the same processes as LRFA-C, albeit a multi-tined radiofrequency electrode will be used to create larger lesions, and the electrode will be positioned perpendicular to the medial branch nerve. The primary objectives of ASTRAL are to 1) compare the effectiveness of LRFA-C with a simulated LRFA control procedure for improving back-related functional limitations, and 2) compare the effectiveness of LRFA-M with a simulated LRFA control procedure for improving back-related functional limitations. The ASTRAL Study also aims to explore the difference in effectiveness, procedure duration, radiation dosage, and pain intensity between LRFA-C and LRFA-M.