Discussion
lumbar pain, lumbar facet joint pain, FJI, depression, pain, somatoform disorders, lumbar facet pain, disability
LUMBAR FACET JOINT PAIN, RECRUITMENT, DISORDERS, HEAT, FACET JOINT PAIN
We report outcomes of the first pragmatic randomized trial comparing C-LRFA to FJI for treating lumbar facet pain in patients diagnosed with lumbar facet joint pain using the clinical criterion of ≥80% pain reduction in reponse to dual-comparative MBBs.Patient selection in both research and clinical care is vital and likely contributed to the observed outcomes in the present study. In addition to excluding patients with conditions known to reduce treatment response (ie, widespread pain or somatoform disorders, concomitant lumbar pain disorders, depression, etc.), patients had to experience a positive response to dual comparative MBBs with pain reduction of ≥80% of concordant duration to that expected of two different local anesthetics used on independent occasions.The C-LRFA electrode lesion size and forward-projecting, spherical geometry may have contributed to the positive outcomes observed in this study. C-LRFA electrodes produce a more significant lesion by using an internal perfusate that serves as a heat sink in tissue adjacent to the electrode. Electrode cooling prevents adjacent tissue charing, lowering tissue impedance, and allowing the lesion to develop further from the electrode tip in a spherical shape. The C-LRFA lesion shape and size enable proceduralists to approach the lumbar medial branches from a variety of angles without sacrificing target neural capture, unlike the traditional parallel L-RFA technique. Cendeno et al.Interestingly, there was no significant difference in C-LRFA and FJI responder rates as assessed by ≥15-point or ≥30% ODI reduction. The lack of a between-group difference suggests that C-LRFA does not reduce ODI scores to a greater degree than FJI; however, these findings are more likely due to a small sample size and the lack of a minimum ODI score as a study eligibility criterion (which creates a “floor”-effect). There was a trend that C-LRFA was ∼7 times more likely to result in ≥30% ODI reduction compared to FJI, but this trend did not reach statistical significance (OR 6.92 [95% CI 0.46, 104.10]). Of those participants treated with L-CRFA, 60%, 40%, and 55% achieved ≥30% ODI reduction at 3,6 and 12 months. These rates are similar to the 60% responder rate observed in the only other C-LRFA trial using ODI as a disability outcome measure.This study has limitations, including a lack of participant blinding and small sample size. Blinding participants in this study was not feasible for financial reasons. During study initiation, FJI and C-LRFA were both covered by insurance but had different respective costs. If a patient was blinded, insurance could not be appropriately billed, which would have made the present study prohibitively expensive and not feasible. The absence of participant blinding and issues with obtaining insurance authorization for FJI may partially explain why no participants crossed over to FJI after their index C-LRFA procedure. Non-blinded participants allocated to the C-LRFA study arm may have been less interested in steroid injection if they believed they had already received the “superior” treatment, while insurance denial for FJI could have deterred individuals who were otherwise inclined to pursue this treatment option. The sample size is a significant issue. As reported in our power calculation, we planned to enroll 120 patients (60 in each group). Enrollment was ended before goal recruitment was achieved because of the coverage change for FJI during the study period. It became clear that 1:1 randomization was no longer possible, so the study was ended early. Finally, a large number of patients were screened (all-comers with CLBP) in order to enroll a final total of 32. We used strict inclusion criteria to identify patients with “pure” or highly dominant facet joint pain without significant concomitant pain generators. As such, generalizability of the present findings is limited to individuals with dominant facet joint pain.