Ureteral wall thickness as an imaging-based predictor of difficult ureter during ureteroscopic lithotripsy: a retrospective analysis.

OBJECTIVE

To evaluate the value of ureteral wall thickness (UWT) obtained from non-contrast computed tomography (NCCT) for predicting difficult ureter (DU) among patients receiving ureteroscopic lithotripsy (URS).

METHODS

Patients with unilateral ureteral stones managed by URS were retrospectively reviewed. According to intraoperative findings, they were classified into DU or non-DU group. UWT was measured at the level of the stone on preoperative NCCT. Multivariate logistic regression was used to identify independent predictors. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff value of UWT for predicting DU.

RESULTS

A total of 271 patients managed with URS were enrolled in the study, with 67 (24.72%) in the DU group and 204 (75.28%) in the non-DU group. The mean UWT in the DU group was 3.77 ± 1.24 mm, which was significantly higher than that in the non-DU group. Multivariate logistic regression revealed that UWT was an independent risk factor for DU, with an OR of 2.139 (95% CI: 1.634-2.79). The ROC curve demonstrated that a UWT cutoff of 2.9 mm provided the best threshold for predicting DU, with sensitivity and specificity levels of 77.6% and 71.6%, with an area under the ROC curve (AUC) of 0.786. Moreover, a UWT greater than 2.9 mm was associated with abnormal endoscopic findings during surgery, prolonged operative time, and a reduced stone-free rate.

CONCLUSION

UWT is an independent risk factor for DU. Preoperative measurement of UWT holds significant value in predicting DU. These findings may assist in surgical planning before URS.