Sheathless RIRS in the era of slim and single use flexible ureteroscopy (ssFURS): Prospective analysis of clinical outcome

Introducation: the purpose is to assess the feasibility of sheathless and time-limited retrograde intrarenal surgery (RIRS) using slim and single use flexible ureteroscopy (ssFURS) in view of the stone-free rate (SFR), complication rate and upfront ureteral stenting. Methods: A prospective, cross-sectional study of patients who underwent RIRS for kidney stones between December 2021 and December 2023 at our tertiary urology center was performed. Patient demographics, clinical presentations and stone characteristics were calculated. The SFR and complication rate were included. Results: Hundred and eighteen patients were included. The median age was 48 (35.7–60.0) years. Diabetes mellitus (DM) was present in 32 patients (27.1%). The median length of the kidney stones was 1.15 (range 0.4–3.0), and the median width was 1 (range 0.05–3.7). The pelvi-ureteric junction (PUJ) represented 75 (63.6%) patients. The lower pole stone (LP) consisted of 27 (22.9%) patients. Thirty-seven (31.4%) of the patients had multiple kidney stones. An overall complete SFR after the first session was observed for 94 (79.7%) patients. The second session of complete SFR was observed in 15 patients (12.7%). A median stone length of 1 (0.8–1.5) cm and a median stone width of 0.95 (0.7–1.3) cm were both significantly associated with a complete SFR after the first session ( p < 0.001). A single kidney stone in 69 (73.4%) patients was significantly more strongly associated with a complete SFR after the first session than was multiple kidney stones in 25 (26.6%) patients ( p = 0.027). Upfront stenting was performed in 74 patients (62.7%). The complete SFR after the first session was significantly greater in patients who underwent upfront stenting (65; 69.1%) than in those who underwent primary ssFURS (29; 30.9%, p = 0.004). Conclusion: Sheathless and time-limited RIRS using ssFURS is a feasible and successful procedure with low complication rate.