External Validation and Comparison of Current Scoring Systems in Encrusted Ure-teral Stent Management: a Multicenter Study.

Purpose: To compare the external validation of four existing scoring systems for encrusted ureteral stents (EUS) and their relationship with stent indwelling time, stone-free rates, multiple surgery sessions, multimodal procedures, and prolonged operation times exceeding 120 minutes in total.

Materials and methods: The data of 208 patients who underwent surgery for EUS reviewed. All EUSs were evaluated with 4 scoring systems: ESB (encrusted stone burden), FECal (forgotten, encrusted, calcified), KUB (kidney, ureter and bladder), V-GUES (visual grading for ureteral stone burden).

Results: As the duration of stent indwelling time prolonged, a significant increase is observed in the scores of ESB, FECal, KUB and V-GUES systems (p<0.001). In multivariate logistic regression analysis, V-GUES score (p=0.025) and stent indwelling time (p=0.014) in stone-free rate, FECal grade (p<0.001) in multimodal procedure requirement, FECal (p=0.002) and V-GUES (p=0.032) scores in multiple surgery sessions, and stent indwelling time (p=0.019) and KUB score (p<0.001) in prolonged operation time were found to be predictors. When the area under receiver operating characterictic (ROC) curves (AUC) of the nomograms were examined, V-GUES score (AUC=0.685) in stone-free rate, FECal grade (AUC=0.780) in multimodal procedure requirement, FECal grade (AUC=0.845) in multiple surgery sessions, and KUB score (AUC=0.860) in prolonged operation time were found to be superior.

Conclusions: The management of EUSs is often challenging for urologists. Although the current scoring systems for EUS differ somewhat, it is important to use scoring systems to guide the management of these patients.