Ureteral Wall Thickness as a Preoperative Indicator of Impacted Stones in Patients With Ureteral Stones Undergoing Ureteroscopic Lithotripsy.

OBJECTIVE: To evaluate the clinical significance of ureteral wall thickness (UWT) to predict the presence of impacted stones in patients with ureteral stones undergoing ureteroscopic lithotripsy (URSL).

MATERIALS AND METHODS: We retrospectively analyzed 130 procedures in patients with ureteral stones who underwent URSL between January 2014 and September 2016. Maximum UWT at the stone site was measured from computed tomography images. Clinical predictors of impacted stones were assessed using univariate and multivariate logistic regression analyses. Receiver operating characteristic curve analysis was applied to determine the UWT cutoff value and to evaluate its accuracy in predicting impacted stones. Moreover, we evaluated the association between UWT and endoscopic findings, as well as surgical outcomes.

RESULTS: Of the 130 procedures, 50 (38.5%) involved patients with impacted stones. The univariate analysis showed significant differences in age, hydronephrosis, stone location, stone burden, and UWT in patients with and without impacted stones, and the multivariate analysis showed that age, stones in the middle ureter, and UWT (odds ratio 5.43, P < .001) were independent predictors of impacted stones. The receiver operating characteristic analysis showed that 3.49 mm was the optimal cutoff value for UWT, with a predictive accuracy of 0.87. High UWTs were associated with the presence of ureteral edema, polyps, white lesions, stone fixation, longer operation time, and lower endoscopic stone-free rate, compared with low UWTs (P < .05 each).

CONCLUSION: High UWT is associated not only with a higher risk of impacted stones but also with poor endoscopic findings and adverse surgical outcomes in patients with ureteral stones undergoing URSL.