The effectiveness of radiofrequency ablation of medial branch nerves for chronic lumbar facet joint syndrome in patients selected by guideline-concordant dual comparative medial branch blocks

Abstract

Objectives. Although the effectiveness of lumbar medial branch radiofrequency ablation (RFA) for the treatment of zygapophyseal joint (z-joint)-mediated low back pain has been characterized, few studies have described outcomes in patients selected using a guideline-concordant paradigm of ≥80% pain relief with dual comparative medial branch blocks (MBBs).We investigated long-term treatment outcomes of patients selected according to this paradigm. Design. Cross-sectional cohort study. Methods. The medical records of 111 consecutive patients were reviewed; 85 met inclusion criteria. A standardized telephone survey was used to capture current numerical rating scale (NRS) and Patient Global Impression of Change (PGIC) scores. The primary outcome was the proportion of patients reporting ≥50% reduction of index pain. Binary logistic regression analysis was performed to explore associations between the primary outcome and covariates, including age, duration of pain, presence of scoliosis, degenerative spondylolisthesis, and >75% disc height loss. Results. At six to 12, 12-24, and >24months, 63.2% (95% confidence interval [CI] = 41-85%), 65.6% (95%CI = 49-82%), and 44.1% (95% CI = 27-61%) of patients reported a ≥50% pain reduction (P=0.170), respectively. At a minimum of six months, 70.6% of patients reported a pain reduction of two or more points (minimally clinically important change), and 54.1% reported a PGIC score consistent with "much improved"or better. Older age and a smaller Cobb angle were associated with a ≥50% pain reduction (P<0.05). Conclusion. Lumbar medial branch RFA is an effective, durable treatment for a significant proportion of patients with recalcitrant lumbar z-joint pain when candidacy is determined by the guideline-concordant paradigmof ≥80% pain relief with dual comparative MBBs.