Introduction & Objectives
This study aimed to evaluate the ability of ureteral wall thickness (UWT) to predict the presence of impacted stone and adverse surgical outcomes in patients with ureteral stone undergoing ureteroscopy (URS).
Material & Methods
Using prospective single-center database of 353 URS procedures between January 2014 and September 2016, we retrospectively analyzed 130 procedures in patients with ureteral stone. The maximum value of ureteral wall thickness at the impacted stone site was measured from axial CT image as UWT. The clinical variables were assessed using univariate analysis and multivariate logistic regression. The receiver operating characteristics (ROC) curve was applied to determine the optimal cut-off value of UWT and evaluate its predictive accuracy for the presence of ureteral stone impaction.
Of 130 procedures, 50 (38.5%) were patients with impacted stone. On univariate analysis, there were statistically significant difference between impacted stone group and non-impacted stone group in terms of age, hydronephrosis, stone location, stone burden, and UWT. Using these variables, we found that age, middle ureter, and UWT (odds ratio, 5.43; P < 0.001) remained as the independent predictor for the presence of impacted stone on multivariate analysis. According to ROC analysis, 3.49 mm was the optimal cut-off value of UWT, with the predictive accuracy of 0.87. High UWT group (≥ 3.49 mm) had worse operation-related data, including longer operative time (80 min vs 59 min, P = 0.002), higher rate of impacted stone (78.7% vs 15.7%, P < 0.001), and lower endoscopic stone-free rate (87.2 % vs 96.4, P = 0.005), compared with low UWT group (< 3.49 mm).
High UWT is associated with a higher risk of impacted stone and adverse surgical outcome. UWT is easy to obtain, and may provide urologist with useful information regarding failure of shock wave lithotripsy and difficulty of surgical procedure, before stone treatment.