A Novel Ureterorenoscope for the Management of Upper Urinary Tract Stones: Initial Experience from a Prospective Multicenter Study

Purpose: This prospective single-arm multicenter clinical trial was conducted to evaluate the safety and efficacy of the Sun's tip-flexible semirigid ureterorenoscope (tf-URS) when used for managing upper urinary tract stones. Patients and Methods: Data from patients who underwent ureteroscopy using the tf-URS for proximal and renal stone removal were prospectively collected from seven Chinese clinical centers. The primary study end point was the stone clearance at the 2-week follow-up. Other data associated with the procedure were also collected. Results: Between October and December of 2014, this study enrolled a total of 254 patients; among which, 235 patients were eligible for ureteroscopy, 216 of whom were treated using the tf-URS. Among all treated patients, 135 had proximal ureteral stones (group 1) while 81 had renal stones (group 2). The overall success rate of endoscope advancement was 91.9% (216/235). The mean fragmentation times were 17.5 +/- 12.6 minutes and 23.3 +/- 15.1 minutes for groups 1 and 2, respectively, and corresponded to an experience-dependent increase in fragmentation speed in both groups. The mean operative times were 31.9 +/- 15.5 minutes and 39.5 +/- 2 0.3 minutes for groups 1 and 2, respectively. The access rate to renal stones in group 2 was 96% (76/81). All treated patients were assessed during a 2-week follow-up period. The stone-free rates at the 2-week follow-up for groups 1 and 2 were 98.7% (133/135) and 91.3% (74/81), respectively. Adverse events were observed in 7.3% (16/216) of the patients; however, all were classified as Grade I or Grade II complications. Conclusions: Based on our initial experience in the current study, the tf-URS can be safely and effectively used to manage proximal ureteral and renal stones with a low rate of complications. Future studies are needed to focus on a transverse comparison between the tf-URS and conventional ureteroscopes.