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.