Randomized prospective trial of cooled versus traditional radiofrequency ablation of the medial branch nerves for the treatment of lumbar facet joint pain

Abstract

Background and objectives: No previous study has assessed the outcomes of cooled radiofrequency ablation (C-RFA) of the medial branch nerves (MBN) for the treatment of lumbar facet joint pain nor compared its effectiveness with traditional RFA (T-RFA). This study evaluated 6-month outcomes for pain, function, psychometrics, and medication usage in patients who underwent MBN C-RFA versus T-RFA for lumbar Z-joint pain.

Methods: In this blinded, prospective trial, patients with positive diagnostic MBN blocks (>75% relief) were randomized to MBN C-RFA or T-RFA. The primary outcome was the proportion of 'responders' (≥50% Numeric Rating Scale (NRS) reduction) at 6 months. Secondary outcomes included NRS, Oswestry Disability Index (ODI), and Patient Global Impression of Change.

Results: Forty-three participants were randomized to MBN C-RFA (n=21) or T-RFA (n=22). There were no significant differences in demographic variables (p>0.05). A ≥50% NRS reduction was observed in 52% (95% CI 31% to 74%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.75). A ≥15-point or ≥30% reduction in ODI score was observed in 62% (95% CI 38% to 82%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.21).

Conclusions: When using a single diagnostic block paradigm with a threshold of >75% pain reduction, both treatment with both C-RFA and T-RFA resulted in a success rate of approximately 50% when defined by both improvement in pain and physical function at 6-month follow-up. While the success rate was higher in the C-RFA group, this difference was not statistically significant.

Trial registration number: NCT02478437.

Conflict of interest statement

Competing interests: ZLMcC serves on the board of directors for the Spine Intervention Society. The authors otherwise declare no potential conflicts of interest.

© American Society of Regional Anesthesia & Pain Medicine 2019. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

FIGURE 1.

Cooled RFA probe placements in (a) oblique, (b) anterior-posterior, and (c) lateral fluoroscopic views for left L4 medial branch nerve and the left L5 dorsal ramus.

FIGURE 2.

Flowchart of patient inclusion and exclusion during study.

FIGURE 3a.

Individual responses in NRS score at 6 months post-intervention, quantified by percent change from the baseline values.

FIGURE 3b.

Individual responses in ODI score at 6 months post-intervention, quantified by percent change from baseline values.

FIGURE 4.

Treatment success was defined as ≥ 50% reduction in NRS pain score, and either ≥ 30% or ≥ 15 points reductions for ODI

Figure 5a.

Changes in NRS by RFA type, estimated by the generalized estimating equation.

Figure 5b.

Changes in ODI by RFA type, estimated by the generalized estimating equation.