Ureteral Diameter as Predictor of Ureteral Injury during Ureteral Access Sheath Placement

OBJECTIVE To determine the association between ureteral diameter and ureteral injury during ureteral access sheath (UAS) placement. METHODS Patients were prospectively enrolled in the study from July 2014 to September 2015. All patients had a preoperative non-contrast computerized tomography (CT) scan and had a 12/14F UAS placement without pre-stenting. A measurement of proximal ureteral diameter was carried out by two urologists and one radiologist. Ureteral wall injuries were evaluated by two endourologists using the 5 grades classification. RESULTS A total of 68 patients were included and the overall success rate for sheath placement was 94.1% (64/68). Among this group, 71.9% (n=46) had evidence of any type of injury to the ureter wall and the rate of high-grade injuries was 26,1% (12/46). The ureteral diameter of patients who had a high-grade injury was significantly smaller compared to those with low-grade injuries (3.29±0.46 mm vs 4.5±0.97mm, p< 0.001). On multivariate analysis, narrower proximal ureteral diameter was associated with a higher risk for high-grade ureteral injury (OR 2.8, 95%CI 1.9-3.4, P< 0.001), regardless of age, gender, body mass index (BMI), middle and distal ureteral diameter. CONCLUSION The proximal ureteral diameter is associated with high-grade ureteral injury. A smaller ureteral diameter increases the risk and the severity of ureteral injury. Therefore, preoperative measurement of the ureteral diameter is recommended for UAS placement to predict the risk of ureteral injury.