Medial branch blocks are the preferred diagnostic method before radiofrequency ablation, with high-quality clinical practice guidelines providing weakly-for recommendations that RF should only be performed after positive response to medial branch blocks 1, 2
Intraarticular facet joint blocks have limited evidence for their diagnostic value in predicting successful outcomes from radiofrequency ablation compared to medial branch blocks 3, 4

Evidence Supporting Medial Branch Blocks

Diagnostic medial branch blocks using local anesthetics with a threshold of >50% pain relief are recommended to confirm facet-mediated pain before proceeding to radiofrequency ablation 5
Current clinical practice guidelines strongly support confirmatory diagnostic facet nerve blocks (medial branch blocks) before proceeding to radiofrequency ablation 1, 2

Clinical Implications

The American Society of Anesthesiologists recommends conventional radiofrequency ablation of the medial branch nerves for facet-mediated pain only when previous diagnostic medial branch blocks have provided temporary relief 5
For patients with chronic axial low back pain, a positive response to two diagnostic medial branch blocks with greater than 80% pain relief is a key criterion for proceeding to radiofrequency facet denervation 6

High-quality clinical practice guidelines provide a strongly-for recommendation supporting confirmatory diagnostic facet nerve blocks (medial branch blocks) before proceeding to radiofrequency ablation, as recommended by the American Society of Anesthesiologists 7, 8
No prior spinal fusion surgery at the levels to be treated, a criterion met by the patient 7
Conservative treatments have been attempted including medications and the patient has undergone prior interventional procedures, as documented in the clinical history 7

A single positive block has insufficient specificity to justify an irreversible denervation procedure, and two positive diagnostic blocks are required to reduce false-positive rates and ensure that the pain relief is reproducible and truly facet-mediated 7, 8
The second block serves as essential confirmation that the initial positive response was not a false positive and that facet-mediated pain is the primary pain generator despite the coexisting HNP 7, 8