A Pilot Study Evaluating Erector Spinae Block Versus Saline For Emergency Department Patients With Ureterolithiasis

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.

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.

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.

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.

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.