MOHEY A, ALHEFNAWY M, MAHMOUD M, GOMAA R, SOLIMAN T, AHMED S, NOURELDIN YA. Fluoroless ureteroscopy for definitive management of distal ureteral calculi: randomized controlled trial. Can J Urol 2018;25(1):0000-0000. Introduction: To assess the conversion rate during fluoroless-ureteroscopy (URS) and evaluate the feasibility, safety, and efficacy of fluoroless-URS as a definitive management of distal ureteral calculi. Material and methods: Between May 2013 and August 2015, patients with radio-opaque distal ureteral calculi of ≤ 1 cm in size were randomized to undergo fluoroless- URS or standard URS. Patients with previous ureteral surgery, ureteral kinking, ureteral stricture, single kidney, additional proximal ureteral or renal calculi, uncontrolled coagulopathy, and/or congenital anomalies of the urinary tract were excluded. Patients’ demographics, stone characteristics, operative data, stone free status, and complications were compared between both groups. Results: Seventy-four cases in the fluoroless-URS group were compared with 80 cases in the standard-URS group. There was no significant difference in the baseline characteristics between both groups in terms of the mean patient’s age (28.8 ± 13.3 versus 29.5 ± 14.6 years; p = 0.76), body mass index (28.2 ± 33 versus 27.6 ± 2.3 kg/m2; p = 0.19), and stone size (7.2 ± 1.5 versus 7.3 ± 1.7 mm; p = 0.70), respectively. Furthermore, there was no significant difference in the outcome parameters between both groups in terms of operative time (42.4 ± 8.3 versus 40.3 ± 6.5 min; p = 0.08), stone free rate (93.2% versus 95%; p = 0.06), and overall complications (12.2% versus 8.75%; p = 0.08), respectively. There was significant difference between both techniques in terms of fluoroscopy time (p < 0.001). However, 6 (7.5%) fluoroless-URS cases necessitated the use of fluoroscopy intraoperatively. Conclusion: Ureteroscopic management of distal ureteral stones using fluoroless-URS technique could be feasible and safe, without radiation exposure for patients and medical personnel. However, fluoroscopy should always be available during fluoroless-URS.