Parallel Versus Perpendicular Technique for Lumbar Medial Branch Radiofrequency Neurotomy

Randomized Trial Comparing Parallel Versus Perpendicular Technique for Lumbar Medial Branch Radiofrequency Neurotomy

Low back pain is a leading cause of disability worldwide. The lumbar zygapophyseal joints (z-joints) are estimated to be the source of low back pain between 10% and 40% of the time. Observational studies have shown that lumbar medial branch radiofrequency neurotomy (LMBRFN) can be an effective treatment for z-joint low back pain. Nonetheless, other publications such as the Cochrane collaboration systematic review and the "Minimal Interventional Treatments for Participants with Chronic Low Back Pain" or "MINT" randomized controlled trial conclude that LMBRFN is not efficacious. These discrepancies in the literature may be due to differences in patient selection and procedural technique. This study aims to employ patient selection via dual medial branch block resulting in at least 80% relief on both occasions. Using this rather strict enrollment criteria, the aim of the study is to then compare LMBRFN utilizing 16 gauge needles via the "parallel" approach as endorsed by Spine Intervention Society guidelines to LMBRFN performed with 22 gauge needles and another commonly employed "perpendicular" technique similar to that approach used for medial branch blocks. The primary outcome of the study will be to determine if there is a difference in the percentage of patients with lumbar facet pain who achieve moderate or good response (improvement of Numeric Pain Rating Scale of at least 50% or 80%) or in the duration of effect (median duration of moderate or good response in those with positive outcome) between these two groups.

Inclusion Criteria:

• aged > 40, capable of understanding and providing consent in English, capable of complying with the outcome instruments used, capable of attending all planned follow up visits
• unilateral or bilateral low back pain of at least 4/10 on Numeric Pain Rating Scale (NPRS) present for at least 2 months that has failed to adequately respond to at least 6 weeks of physical therapy and oral pain medication
• at least 80% improvement on two consecutive lumbar medial branch blocks of no more than a total of 4 lumbar facet joints
• beyond the above stated criteria, the decision to initiate the process of a first medial branch block is based on clinical decision making of the treating physician
• Patient consents to treatment in a shared decision-making process with the treating physician.

Exclusion Criteria:

• Those whose primary complain is lumbar radiculopathy
• Those receiving remuneration for their pain treatment (e.g., disability, worker's compensation).
• Those involved in active litigation relevant to their pain.
• Those unable to read English and complete the assessment instruments.
• Those unable to attend follow up appointments
• The patient is incarcerated.
• History of prior lumbar fusion
• Progressive motor deficit, and/or clinical signs of cauda equina or polyradiculopathy
• History of lumbar steroid injection (epidural steroid injection, sacroiliac joint steroid injection, lumbar facet steroid injection) within the prior 3 months.
• Possible pregnancy or other reason that precludes the use of fluoroscopy.
• Allergy to contrast media or local anesthetics.
• BMI>40.
• Active Systemic inflammatory arthritis (e.g., rheumatoid arthritis, ankylosing spondylitis, lupus).
• Active infection or treatment of infection with antibiotics within the past 7 days.
• Medical conditions causing significant functional disability (e.g., stroke, COPD)
• Chronic widespread pain or somatoform disorder (e.g. fibromyalgia).
• Addictive behavior, severe clinical depression, or psychotic features.