Outcomes of flexible ureterorenoscopy for solitary renal stones in the CROES URS global study

Abstract

Purpose We determined the efficacy and safety of flexible ureterorenoscopy for single intrarenal calculi and further stratified efficacy by stone burden. Materials and Methods CROES collected prospective data on consecutive patients with urinary stones treated with ureterorenoscopy at 114 centers worldwide for 1 year. Only patients who underwent flexible ureterorenoscopy for a solitary renal stone were included in study. Preoperative and intraoperative characteristics, and postoperative outcomes were evaluated. Relationships between stone size and the stone-free rate, operative time, complications, hospital stay and need for re-treatment were determined. Results A total of 1,210 patients with a solitary kidney stone less than 10 (52.2%), 10 to 20 (43.2%) and greater than 20 mm (4.6%) were treated with flexible ureterorenoscopy. The stone-free rate negatively correlated with stone size when adjusted for body mass index. Operative time positively correlated with stone size when adjusted for body mass index. The single session stone-free rate was 90% and 80% for stones less than 10 and less than 15 mm, respectively. Patients with stones greater than 20 mm achieved a 30% stone-free rate, more often needed re-treatment and were more often rehospitalized. There was no difference in the overall complication rate by stone size. However, patients with a stone greater than 20 mm showed a higher probability of fever after flexible ureterorenoscopy than those with a smaller stone. Conclusions Our data indicate that flexible ureterorenoscopy for a single intrarenal stone is a safe procedure. Best results after single session flexible ureterorenoscopy were obtained for stones less than 15 mm.