Randomized Pragmatic Pilot Trial Comparing Perpendicular Thin Electrode Versus Parallel Thick Electrode Approaches for Lumbar Medial Branch Neurotomy in Facetogenic Low Back Pain

Abstract

Objectives: Although there are different ways of performing medial branch neurotomy on facetogenic low back pain, few studies have compared clinical outcomes of a parallel technique over the medial branch vs. a perpendicular technique. We investigated differences in pain outcome with both techniques. Design: This was a prospective, pilot, randomized, pragmatic trial (double blinded in the diagnostic phase). Setting: A comparative pilot trial was conducted at an academic pain center. Methods: Patients who did not respond to conservative medications and had severe lumbar pain for more than 3 months (VAS score ≥ 65) were included. A double diagnostic block with local anesthetic and placebo was performed, double blinded. Patients who had 80% relief from the local anesthetic and no substantial relief from placebo were randomized to undergo medial branch neurotomy under fluoroscopy, placing an electrode parallel or perpendicular to the medial branch. The primary outcome was differences in the VAS score at 1, 3, and 6 months. The secondary outcomes were Oswestry Disability Index score, Roland Morris Questionnaire score, and other functional Likert scale scores. Results: Forty-three consecutive patients were randomized to parallel (n = 20) or perpendicular (n = 23) neurotomy. There were no significant differences in VAS, Oswestry Disability Index, or Roland Morris Questionnaire scores at 1, 3, or 6 months between groups. Statistically significant differences were found in the categorical analysis at 6 months in the evolution of pain, Oswestry Disability Index score, Roland Morris Questionnaire score, and some Likert scale scores in favor of the parallel group. Conclusions: There were differences at 6 months in the categorical analysis of the evolution of pain, Oswestry Disability Index score, Roland Morris Questionnaire score, and some functional Likert scale scores, all in favor of the parallel group. &

3. Pain originating from the lumbar facet joints

“…1,8,26 We also refer to the book "Interventional Pain: A step-by-step guide for FIPP exam". 117 When the proximity of the electrode is confirmed with sensory stimulation, it is important that a near-parallel/ parallel positioning of the electrode is achieved to envelop the targeted nerve in the radiofrequency, as randomized and large retrospective studies have found superiority to a perpendicular approach for lumbar facet joint pain 118,119 (Figure 4). In addition to a greater nerve capture rate (especially in cases where the medial branch is trapped beneath the mamillo-accessory ligament) and effectiveness, animal studies suggest that larger lesions result in longerlasting structural changes, which may translate to longer benefit.…”

Inadequate Selection and Treatment Results in Poor Outcomes and Lack of Cost-Effectiveness

“…Finally, the authors of the letter suggest that "it is important to provide transparency to readers that when more rigorous diagnostic and treatment methods are used in the treatment of low back pain of facet joint origin, substantially higher success rates are obtained, 6 and cost-effectiveness has been demonstrated 7 ." The first reference refers to a small cohort study of 44 subjects who were all treated with radiofrequency denervation.…”

“…The MINT trials have been critiqued by numerous experts in the fields of spine and pain medicine and by various medical societies because of an inadequate patient selection process, critical technical flaws in the execution of the RFD procedure itself, problematic data analysis methods, and potential conflict of interest because of funding by Dutch health insurance companies. [2][3][4][5][6][7] As previously described, an inaccurate protocol was used for establishing a diagnosis of lumbar facet joint pain, leading to inappropriate patient selection in the MINT trials. 3 Although the MINT trials referenced the Spine Intervention Society Guidelines in support of the protocol used to diagnose and select patients with facet joint pain, the published methods document a protocol inconsistent with the Spine Intervention Society Guidelines.…”

“…This critical technical flaw has been discussed in detail elsewhere. [2][3][4][5][6][7] In fact, the technique used is considered by some to be only slightly superior to a sham procedure. The indiscriminate application of RFD to 8 medial branch nerves in every participant in the "facet joint pain" arm is excessive, because it is unlikely that all participants had pain originating from the bilateral lowest 3 facet joints.…”