Effective ureteral access sheath insertion during flexible ureteroscopy: Influence of the ureteral orifice configuration.

ABSTRACT

INTRODUCTION: We sought to determine the possible predictors for effective insertion of the ureteral access sheath (UAS) during flexible ureteroscopy (fURS) in virgin ureters and their impact on postoperative ureteral wall injury and the procedural outcome. METHODS: A retrospective review of prospectively collected data was performed for all consecutive patients scheduled for fURS of virgin ureters at two tertiary care centers between 2018 and 2020. Demographics, stone characteristics, and perioperative data, including the configuration of the ureteral orifice (UO) over introductory guidewire insertion, were collected. Multivariate logistic regression was used to detect possible predictors of successful UAS insertion. RESULTS: In total, 128 patients who underwent primary fURS were included, with a mean age of 43.3±12.3 years and a stone burden of 12.3±6.9 mm. One hundred and ten patients (85.9%) achieved successful ureteral access insertion, including 81 (63.3%) without ureteral dilatation and 35 with dilation, of which 29 (22.7%) had a successful UAS afterward, while six failed. Total patients who underwent ureteral orifice dilatation were 35. 29 had a successful UAS afterward, while 6 failed. Patients who underwent successful UAS placement into virgin ureters were significantly older and had a lower body mass index (BMI). A tent-shaped UO over the guidewire led to successful UAS insertion. In multivariate regression analysis, cases with BMI <30 kg/m2 (odds ratio [OR] 1.89, 95% confidence interval [CI] 1.28-7.03) and those with a tent-shaped UO over the introductory guidewire (OR 6.60, 95% CI 3.8-7.2) maintained their significance to predict successful UAS insertion into virgin ureters. Nine patients (8.2%) had ureteral mucosal injuries, and the overall stone-free rate was 78.2%. CONCLUSIONS: Patients with normal BMIs and tent-shaped UOs over the introductory guidewires are more likely to achieve primary UAS insertion without the need for ureteral dilation.