Impact of forced diuresis on retropulsion of disintegrated ureteral calculi during semi-rigid ureteroscopy: a double-blind randomized-controlled study

The objective of this study is to assess the safety and efficacy of forced diuresis as an antiretropulsion strategy during the pneumatic disintegration of solitary lower ureteric stones with semi-rigid ureteroscopy (URS). A prospective randomized double-blind study was carried out from March 2019 to June 2021 for patients presented with unilateral solitary radiopaque lower ureteric stones ≤ 20 mm. Patients were randomized for URS into two groups, according to the use of forced diuresis using furosemide 1 mg/kg (GII) or not (GI). Perioperative parameters were compared between both groups, including retropulsion rate, stone-free rate (SFR), and need for auxiliary procedures and complications. A total of 148 patients were included; 72 (48.6%) in GI and 76 in the GII (51.4%), with respective stone size of 11.8 ± 2.6 vs.12.1 ± 2.4 mm. Both groups were comparable in demographic and baseline data, with a mean age of 47 ± 16 and 50 ± 14 years for GI and GII, respectively. GII had a significantly shorter disintegration time (10.5 ± 1.3 vs. 4.2 ± 2.1 min, p < 0.001), shorter operative time (33.1 ± 10.1 vs. 40.8 ± 9.1 min, p < 0.001), lower stone fragments migration rate during disintegration (6.5% vs. 18.1%, p = 0.04), lower retropulsion rate (1.3% vs. 11%, p = 0.02), higher SFR (96.1% vs. 86.1%, p = 0.04), and lower auxiliary procedures (3.9% vs. 13.8%, p = 0.03). Intraoperative and 6-h postoperative changes in heart rate and mean systolic blood pressure were comparable between both groups. Ephedrine injection (6–18 mg) was needed in significantly more GII patients (39.5% vs. 20.8%, p ≤ 0.01). It seems that forced diuresis during pneumatic lithotripsy of the lower ureteric stones is a safe and effective antiretropulsion technique. This would expand the alternative options to the antiretropulsion strategy, especially in centers where the laser and flexible ureteroscopes are not available.