Novel scoring system for predicting stone-free rate after flexible ureteroscopy lithotripsy

Area of Science:

• Urology
• Endourology
• Medical imaging

Background:

• Flexible ureteroscopy with laser lithotripsy (fURSL) is a common treatment for renal stones.
• Predicting the stone-free rate (SFR) after fURSL is crucial for patient management and treatment planning.

Purpose of the Study:

• To investigate factors influencing the stone-free rate (SFR) in fURSL for renal stones.
• To develop predictive models for SFR using prognostic factors.
• To construct a nomogram for predicting fURSL outcomes.

Main Methods:

• Retrospective analysis of 252 patients treated with fURSL.
• Evaluation of clinical data, stone characteristics (size, location, CT value, STPR), and operation time.
• Development of two predictive models using multivariate Cox regression and construction of a nomogram.

Main Results:

• Stone location, diameter (D1, D2), CT value (SCTV), stone/transverse process pixel ratio (STPR), and operation time were significant factors.
• Model 1 (D1, location, SCTV) and Model 2 (D2, location, STPR) showed high predictive accuracy (C-indices 0.924 and 0.895).
• The nomogram demonstrated high predictability with no significant difference between the two models.

Conclusions:

• Stone location, size, and density (SCTV, STPR) are significant predictors of SFR after fURSL.
• A scoring system based on these factors can guide optimal treatment strategy selection for renal stones.
• The developed nomogram accurately predicts stone clearance, aiding clinical decision-making.