A Prospective Evaluation of the Association of Ureteral Wall Thickness With Intraoperative Stone Impaction in Ureteroscopy

Background and objective In this study, we aimed to analyze the association of ureteral wall thickness (UWT) measured on non-contrast CT (NCCT) with stone impaction as found in ureteroscopy (URS). Materials and methods We analyzed 43 patients who underwent URS and pneumatic/laser lithotripsy for ureteric stones from May to November 2022. The UWT was measured by an experienced radiologist on NCCT. Clinical predictors of the impacted stone were calculated by univariate and multivariate regression analysis. The receiver operating characteristic (ROC) curve was calculated for the UWT cutoff to apply it for impaction with different parameters. We also evaluated the association of intra- and postoperative parameters of the two groups with UWT. Results Out of the 43 patients with stones, 26 (60.46%) patients had impacted stones. Univariate analysis was used to analyze the site (left-sided stone impacted more commonly), stone size, stone density [Hounsfield unit (HU)], hydronephrosis, UWT, and duration between initial presentation and surgery, and multivariate analysis was utilized to assess stone density, as well as UWT's association with impacted stones. The ROC curve showed a cutoff of 3.5 mm for UWT with an accuracy of 0.83. High UWT (≥3.5 mm) was associated with a significantly lower stone-free rate, more complications, and mean operative time as compared to low UWT (<3.5 mm) (p<0.05). Conclusion Based on our findings, high UWT is associated with high rates of impacted stones and a lower stone-free rate when compared to low UWT.