Asymptomatic versus symptomatic ureteral stones: predictors and nomogram for postoperative renal function recovery

To compare renal function outcomes between asymptomatic and symptomatic ureteral stones and to develop and validate a predictive nomogram for postoperative renal recovery after ureteroscopic lithotripsy (URSL).

This two-center retrospective study included consecutive patients who underwent URSL between March 2018 and March 2023. Patients were categorized into asymptomatic and symptomatic groups. Renal function recovery was defined as a postoperative glomerular filtration rate (GFR) of the affected kidney exceeding 90% of the contralateral side at 1 year. Predictors were identified by logistic regression and incorporated into a nomogram. Model performance was assessed by receiver operating characteristic (ROC) analysis, calibration, and decision curve analysis (DCA), with both internal (bootstrap resampling) and external validation.

Among 635 patients who underwent URSL, 465 (73.2%) demonstrated recovery of renal function at 1 year postoperatively. Asymptomatic stones (n = 38, 5.98%) were associated with larger size, upper ureteral location, severe hydronephrosis, and lower preoperative GFR compared with symptomatic stones. Multivariate logistic regression identified six independent predictors of renal function recovery: older age, diabetes mellitus, higher hydronephrosis grade, complete obstruction, lower preoperative split renal function, and symptomatic status (all p < 0.05). The nomogram incorporating these variables demonstrated good discrimination (AUC = 0.786) and calibration (MAE = 0.02), which was confirmed by external validation (AUC = 0.805; MAE = 0.03). Decision curve analysis (DCA) further indicated superior clinical net benefit across a wide range of threshold probabilities.

Asymptomatic ureteral stones were associated with delayed diagnosis, advanced obstruction, and limited renal recovery. The proposed nomogram provides a validated, individualized tool to estimate recovery probability and may inform early surgical intervention strategies.