Ureteral stricture prediction of occurrence after ureteroscopic lithotripsy

Ureteral stricture is a significant complication after ureteroscopic lithotripsy (URSL). This study aimed to identify risk factors for post-URSL ureteral stricture and develop a nomogram to predict the timing and probability of stricture occurrence within 1-3 years postoperatively, thereby facilitating individualized follow-up.

We enrolled patients who underwent holmium laser ureteroscopic lithotripsy (URSL) at a single institution between January 1, 2014, and December 31, 2021, and were diagnosed with postoperative ureteral stricture. Baseline characteristics, in-hospital data, surgical indicators, computed tomography data, and laboratory test results of patients with and without stenosis were compared. Cases (n = 70) were patients diagnosed with postoperative ureteral stricture; controls (n = 70) were selected using propensity score matching (age, sex, stone laterality, surgery date) from patients without stricture. T-tests, Pearson's chi-squared, or Fisher's exact tests, LASSO and Cox regression analyses, receiver operating characteristic and Kaplan-Meier curve analyses, and nomogram analysis were used to predict post-URSL ureteral stricture risk factors and timing.

Hypertension incidence (P = 0.038), ureteral stent placement time (P = 0.002), stone location (P = 0.04), and hydronephrosis grade (P < 0.001) differed significantly between the groups, and stone impaction were independent risk factors for ureteral stricture. The nomogram showed good discrimination (C-index 0.720) and calibration. Preoperative fever appeared as a protective factor but should be interpreted cautiously due to potential confounding.

The nomogram, which based on hydronephrosis grade, ureteral stone location, and incarcerated stones can predict post-URSL ureteral stricture risk and may guide personalized follow-up. External validation is needed before clinical application.