LAUSR

PURPOSE Retropulsion of stone fragments during ureteroscopic laser lithotripsy (URSLL) remains a challenge for urologists and is associated with increased operative time and reduced stone-free rate (SFR). Herein, we compared the rate of retropulsion of ureteral stones during URSLL between the standard dorsal lithotomy position (SDL) and dorsal lithotomy position with reverse Trendelenburg (RT) Material and Methods: Between May 2019 and January 2022, patients with ureteral stones requiring surgical intervention were randomized to undergo URSLL in either the SDL or RT positions. The primary outcome of the study was the occurrence of stone retropulsion. Secondary outcomes included retropulsion to the kidney, SFR, operative time, 30-day ED visits and complications, and the need for conversion from semi-rigid to flexible ureteroscope. Differences between groups were evaluated using the chi-squared test, Fisher's exact test, Kruskal-Wallis test, or t-test. RESULTS A total of 114 patients were included, with 57 patients in each group. There were no differences between groups in terms of baseline demographics or stone characteristics. Retropulsion was significantly less frequent in the RT group (68.4% vs. 10.5%, p<0.01). Similarly, RT group was favored for lower risk of retropulsion into the kidney (40.4% vs. 5.3%, p<0.01), operative time (43.5 min vs. 33.0 min, p=0.02), and need for ureteroscope conversion (16.7% vs. 2.2%, p=0.04). There was no difference in SFR (100% vs. 95%, p=0.49). CONCLUSIONS RT positioning during URSLL for ureteral stones significantly decreases the rate of stone retropulsion, operative time, and the need for conversion from semi-rigid to flexible ureteroscope.