Ureteral Wall Thickness as an Independent Predictor of Stone Impaction - A Prospective, Single-Center, Observational Study.

Background: Urologists can encounter difficulties when dealing with ureteral stone impaction. However, reliable preoperative indicators of stone impaction are scarce.

Aims: We aimed to determine ureteral wall thickness (UWT) as an independent predictor of intraoperative stone impaction, to detect if any patient or stone-related factors predict impaction and to ascertain whether impaction affected intraoperative/postoperative outcomes.

Methods: We prospectively studied 83 patients who underwent ureterorenoscopic lithotripsy for ureteral stones between October 2023 and March 2024. UWT measurement was done preoperatively on non-contrast computed tomography. Clinical predictors of stone impaction were analyzed by univariate and multivariate analyses. Receiver operator characteristic (ROC) curve analysis was performed to identify the optimal cutoff for independently predicting impaction. We also analyzed intraoperative and postoperative outcomes with respect to impaction.

Results: Out of 83 patients, 46 (55.42%) had impacted stones. Gender, stone laterality, stone size, area, Hounsfield unit, degree of hydronephrosis, duration of symptoms, and UWT had significant association with stone impaction on univariate analysis. When these factors were subjected to multivariate analysis, only UWT and stone area had significant association with impaction. We determined a UWT cutoff of 3.45 mm and a stone area cutoff of 28.62 mm2 for predicting impaction based on ROC analysis. Our study showed that impaction increased the overall duration of the procedure and affected stone clearance rates.

Conclusion: Based on our study, high UWT is associated with a higher risk of stone impaction, prolonged duration of procedure, and lower stone clearance rates.