The effect of distal ureteral lateralization angle on ureteral trauma avoidance and successful ureteral access sheath placement.

Background: The use of ureteral access sheaths (UAS), which offer advantages in flexible ureteroscopic lithotripsy (fURL), may lead to undesirable conditions such as ureteral injury, ischemia, and prolonged ureteral stenosis. The aim of this study was to investigate the effect of the distal ureteral lateralization angle on successful UAS placement.

Methods: We analyzed the data of patients who underwent fURL for kidney and/or proximal ureteral stones retrospectively. Based on the preoperative computed tomographic examinations of the patients, the bladder outlet was considered the zero point. We calculated the angle values between the horizontal axis passing through this point and the most lateralized point of the distal ureter. The patients were divided into two groups: those to whom UAS was successfully placed and those to whom UAS placement failed.

Results: No significant difference was detected between the groups with successful UAS placement (n=36) and those without UAS placement (n=12) in terms of sex, laterality, localization, number of stones, stone burden, and bladder volumes evaluated with preoperative computed tomography (p>0.05). However, a significant difference was found between the two groups regarding age and distal ureteral lateralization angle (p<0.001, p=0.013).

Conclusion: The distal ureteral lateralization angle is considered to be an effective factor in the placement of UAS in patients scheduled for fURS.