Semirigid ureteroscopy prior retrograde intrarenal surgery (RIRS) helps to select the right ureteral access sheath

Objective: To evaluate ureteral compliance through semirigid ureteroscopy (sURS) in order to select the proper ureteral access sheath (UAS) size for retrograde intrarenal surgery (RIRS). Patients and methods: In a prospective study, 100 consecutive patients selected for elective sURS or RIRS were recruited. Each patient, initially underwent 9.5 Fr sURS with a safety guidewire 3Fr, in order to estimate ureteral compliance. If the ureter was compliant, a gently passage of a 12/14Fr UAS was attempted. If the ureter was not deemed compliant, passage of either a smaller UAS or a smaller semirigid 7Fr or a flexible 7.5Fr or a digital 8.5Fr scope with and without safety guidewire, was attempted. Age, gender, disease location, prestenting, previous RIRS and/or stone elimination, hydronephrosis, ureteral strictures, unsuccessful procedures, and complications, were analyzed as possible correlated factors of ureteral compliance. Results: In 77 patients the ureter was deemed compliant ≥ 14Fr. Of the preoperative factors that were examined, stent placement before RIRS (P < 0.002), previous RIRS (P = 0.000) and previous stone elimination (P = 0.004), correlated with ureter ≥ 14Fr. Ureteral lithiasis (P < 0.001), ureteral strictures (P < 0.05), unsuccessful procedures (P < 0.005) and complications (P = 0.01) correlated with ureter < 14Fr. The complication rate was 10% (10 patients) with ureteral injuries grade I in 9 patients and grade III in 1 patient according to the endoscopic grading system. Age, gender, hydronephrosis and urothelial carcinoma (UC) had no influence. Conclusions: sURS performed before RIRS allows selection of the right ureteral access sheath (UAS) and avoidance of major complications. Pre-stenting, previous RIRS and stone elimination history are all factors correlating with a compliant ureter.