Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P50. A randomized prospective comparative trial of water-cooled versus traditional radiofrequency ablation of the median branch nerve in the treatment of zygapophyseal joint pain: six-month outcomes

BACKGROUND CONTEXT No study has compared the effectiveness of water-cooled radiofrequency ablation (WC-RFA) and traditional RFA (T-RFA) of the medial branch nerves (MBNs) for lumbar zygapophyseal joint (Z-joint) pain. PURPOSE Evaluate six-month pain, functional, psychometric, and medication usage outcomes of MBN WC-RFA versus T-RFA for lumbar Z-joint pain. STUDY DESIGN/SETTING Randomized comparative trial at an urban, tertiary, academic spine or pain center. PATIENT SAMPLE Individuals with Z-joint pain diagnosed by clinical evaluation and positive diagnostic MBN blocks (u003e50% relief) were randomized to WC-RFA or T-RFA. OUTCOME MEASURES The primary outcome was the proportion of “responders” (≥50% NRS reduction) at 6-months. Secondary outcomes included the NRS, ODI, Patient Anxiety Symptom Scale (PASS-20), McGill Pain Inventory (MPI), Center for Epidemiologic Studies Depression scale (CESD-10), daily morphine equivalents (DME), and Patient Global Impression of Change (PGIC). METHODS Six-month clinical outcomes were compared in the the group that was randomized to WC-RFA and the group that was randomized to T-RFA. Data were analyzed by descriptive statistics, chi-square tests, one-sample t -tests, independent t -tests, and Mann-Whitney-Wilcoxon tests RESULTS Forty participants (mean age=55.9, 24 females, mean BMI 30.2 kg/m 2 ) underwent MBN WC-RFA (n=21) or T-RFA (n=19). There were no differences in demographic variables (pu003e.05). A ≥50% NRS reduction was observed in 52% (95% CI 31%–74%) and 47% (95% CI 26%–71%) of participants undergoing WC-RFA and T-RFA, respectively, at 6 months (p=.75). A ≥15-point or ≥30% reduction 6 months was observed in 62% (95% CI 39%–80%) and 42% (95% CI 22%–66%) of participants in the WC-RFA and T-RFA groups, respectively (p=.21). Significant reductions in mean NRS and ODI scores were observed in both groups: WC-RFA (NRS 7.4–3.6; ODI 29–18) and T-RFA (NRS 7.1–4.2; ODI 26–19) (NRS p 0.05). CONCLUSIONS Approximately half of participants reported clinically meaningful improvements in pain and function with MBN WC-RFA and T-RFA at 6 months, with no intergroup differences observed. These results are representative of a selection protocol with a high false-positive rate; use of dual comparative MBN blocks for patient selection would likely result in a higher success rate regardless of RFA modality.