Pilot RCT finds non-significant pain reduction with ESPB ropivacaine versus saline for ureteral stones

BACKGROUND: Ureterolithiasis is a major cause of severe flank pain in the Emergency Department (ED). Given the disadvantages of opioids, alternative yet effective therapies for ureterolithiasis are sorely needed. OBJECTIVES: To determine the feasibility and analgesic efficacy of an erector spinae plane block (ESPB) with ropivacaine 0.5% compared with normal saline (NS) in patients with ureterolithiasis. METHODS: We conducted a single-blinded, randomized clinical trial, on a convenience sample of adult ED patients with ureteral stones with a numeric pain score of > 4. Baseline characteristics were recorded, and patients were randomly allocated to an ESPB using 20 mL ropivacaine 0.5% or NS. Pain scores were recorded at 10, 20, 40, and 60 minutes. Between-group pain scores were compared with a Mann Whitney U test and repeated measures analysis of variance. RESULTS: The study included 24 patients, 12 in each of the study groups. Mean (SD) age was 45.6 (12.8) years, 54% were male. Baseline pain scores were similar in both groups. Median (IQR) pain scores at 60 minutes were 1 (0-3.7) and 4 (1.2-5) in patients randomized to ropivacaine and NS, respectively (p = 0.11). Patient satisfaction scores and time to discharge were similar in both groups. CONCLUSIONS: In this pilot study of ED patients with ureterolithiasis performance of a randomized controlled trial (RCT) comparing ESPB with ropivacaine and NS was feasible and showed clinically significant differences but not statistically significant between-group differences in pain scores. The study also raises the possibility that fascial plane injection of NS may have analgesic benefit as well.