A randomized prospective study: assessment of transient ureteral stenting by mono-J insertion after primary URS and stone extraction (FaST 3).

To compare the outcome of a short-term insertion of a mono-J catheter for 6 h following ureteroscopic stone removal to a conventional double-J catheter. This single-center academic study (Fast Track Stent study 3) evaluated stenting in 108 patients with urinary calculi after ureterorenoscopy. Patients were prospectively randomized into two study arms before primary ureterorenoscopy: (1) mono-J insertion for 6 h after ureterorenoscopy and (2) double-J insertion for 3-5 days after ureterorenoscopy. Study endpoints were stent-related symptoms assessed by an ureteral stent symptom questionnaire (USSQ) and reintervention rates. Stone sizes and location, age, operation duration, BMI, and gender were recorded. Of 67 patients undergoing ureterorenoscopy, 36 patients were analyzed in the double-J arm and 31 patients in the mono-J arm. Mean operation time was 27.5 ± 1.3 min versus 24.0 ± 1.3 min, and stone size was 5.2 mm versus 4.5 mm for mono-J versus double-J, respectively (p = 0.06 and p = 0.15). FaST 3 was terminated early due to a high reintervention rate of 35.5% for the mono-J group and 16.7% for the double-J group (p = 0.27). One day after ureterorenoscopy, USSQ scores were similar between the study arms (Urinary Index: p = 0.09; Pain Index: p = 0.67). However, after 3-5 weeks, the Pain Index was significantly lower in those patients who had a double-J inserted after ureterorenoscopy (p = 0.04). Short-term insertion of mono-J post-ureterorenoscopy results in similar micturition symptoms and pain one day after ureterorenoscopy compared to double-J insertion. The reintervention rate was non-significant between the treatment groups most likely due to the early termination of the study (p = 0.27). Ethics approval/Trail Registration: No. 18-6435, 2018.