Intra-articular Steroids vs Saline for Lumbar Z-Joint Pain: A Prospective, Randomized, Double-Blind Placebo-Controlled Trial

Objective To determine if intra-articular (IA) injection of corticosteroids is effective in reducing the need for radiofrequency ablation (RFA) in those with dual comparative medial branch block (MBB)-confirmed lumbar z-joint pain. Design This was a randomized, double blind, placebo-controlled study. Setting Two academic medical centers. Subjects Fifty-six consecutive subjects who had 80% pain relief during an initial screening MBB were recruited. Methods Patients received a second confirmatory MBB and concurrent IA injection of either corticosteroid or saline per randomization. Twenty-nine of 56 received intra-articular corticosteroid (triamcinolone 20mg), of whom 24 also had a positive confirmatory MBB per Spine Interventional Society guidelines, with 80% pain relief from both MBBs. Twenty-seven of 56 received IA saline into the z-joint during the confirmatory MBB, of whom 22 also had a positive confirmatory MBB. The primary outcome measure was the categorical need for RFA due to insufficient pain relief with intra-articular injection, and the secondary outcome was time to RFA. Results There was no statistically significant difference in the need for an RFA between the groups (16/24 steroid, 67%, 95% confidence interval [CI]=47-82%) vs 15/22 saline (68%, 95% CI=47-84%, P=1.00). The average time to RFA was also not different, at 6.00weeks for steroids vs 6.55weeks for saline (P=0.82). Conclusions Intra-articular corticosteroids were not effective in reducing the need for or the time to a radiofrequency ablation of the medial branches in those with dual MBB-confirmed lumbar z-joint pain.