Lumbar Medial Branch Radiofrequency Ablation: Technical Suggestions Based on Emerging Ex-Vivo Evidence.

BACKGROUND

Facetogenic pain accounts for 5-50% of chronic low back pain (CLBP) cases, and the prevalence of this pain increases with age. Because of poor imaging correlation, the diagnosis is challenging and relies on symptoms, exam findings, and "gold standard" diagnostic blocks, though optimal protocols remain debated. National societies have issued treatment recommendations for the condition, yet controversy persists. The present investigation focuses on medial branch block radiofrequency ablation (RFA) and highlights key factors for optimizing technique to improve patient outcomes.

OBJECTIVES

To demonstrate proper technique and factors that clinicians should consider to maximize the effectiveness of MBN RFA.

STUDY

DESIGN

Development of methodology integrating ex vivo evidence and clinical approach.

SETTING

An academic healthcare institution.

METHODS

A PubMed review of article published between 2020 and 2025 was performed using the keywords "ex vivo," "radiofrequency ablation," and "lesion size." RFA of medial branch nerves (MBNs) relies on precise anatomical knowledge to ensure proper needle placement. Recent studies have demonstrated that there are multiple factors to consider in MBN RFA. When compared to muscle, adipose reduces lesion size in relation to lower thermal conductivity. Adipose around the needle decreases lesion size, which may explain the reduced efficacy of RFA in obese patients. Commonly used solutions impact lesion dimensions: 2% lidocaine increases lesional width, while iohexol 240 increases length. In addition, a probe's proximity to bone increases lesion size, as poor thermal conductance traps energy in adjacent tissues. Therefore, shape and size can be modified in accordance with medication selection and the active tip's juxtaposition to tissue.

LIMITATIONS: Despite advancements, significant knowledge gaps remain in understanding the effectiveness of RFA, since most studies focus on tumor ablation rather than neurolysis, and lack in-vivo data. To improve real-world clinical outcomes, future research should evaluate functional outcomes and pain relief in patients undergoing individualized procedures tailored to their unique anatomy.

CONCLUSIONS

RFA of MBNs is a valuable way to treat axial, facetogenic low back pain. The technique should be optimized to best account for the unique anatomy of each patient and thereby maximize the effectiveness of the procedure.