Presented by: Sobhi Khoury MD
Carmel Medical Center, Haifa, Israel

Introduction

Ureteral access sheath (UAS) has become an invaluable tool in retrograde intrarenal surgery (RIRS). However it’s insertion may sometimes fail, usually due to a tight ureter. We aimed to assess whether UAS insertion failure can be predicated based on ureteral diameter measured on non-contrast computerized tomography (NCCT) and to identify demographic, clinical, and operative risk factors associated with failure.

Materials

This is a single centre retrospective study, the study group included all  previously unstented patients who underwent primary RIRS with failure of UAS insertion between 2017 and 2022 and a group of randomly selected patients with successful UAS insertion. Demographic and clinical data were collected, as well as radiographic characteristics, operative data and complications. Ureteral diameter was measured by a single radiologist at predefined points on axial NCCT images. 

Results

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There were 33 consecutive cases of UAS insertion failure included in the study, and 71 successful cases that were randomly selected. No statistically significant differences were found regarding age, sex, BMI and previous history of ipsilateral procedures between the groups. The ureteral diameter at the crossing level of the iliac vessels and the ureterovesical junction (UVJ) was significantly smaller in the study group (p=0.02), with cut-off values of 4 mm at the level of the iliac vessels (88 % sensitivity and 62% specificity) and 3 mm at the  UVJ level (84 % sensitivity and 58% specificity).

Conclusion

Measuring the ureteral diameter on NCCT at the crossing level of the iliac vessels and the UVJ can indicate failure in UAS insertion during ureteroscopy for unstented patients. 

Funding

None

Lead Authors

Ilan Klein, MD
Carmel Medical Center, Haifa, Israel

Co-Authors

Mohammad Ali, MD
Carmel Medical Center, Haifa, Israel

Mohammad Shalabi, MD
Carmel Medical Center, Haifa, Israel

Yuval Freifeld, MD
Carmel Medical Center, Haifa, Israel

Rani Zreik, MD
Carmel Medical Center, Haifa, Israel

Maharan Kabha, MD
Carmel Medical Center, Haifa, Israel

Gazi Fares, MD
Carmel Medical Center, Haifa, Israel

Natalia Goldberg, MD
Carmel Medical Center, Haifa, Israel

Yoram Dekel, MD
Carmel Medical Center, Haifa, Israel