UP-81 Ureteral wall thickness as a novel predictor for failed retrograde stent placement
Thursday June 27, 2019 from
TBD
Presenter

Nick S Dean, Canada

Resident

Division of Urology

University of Alberta

Abstract

Ureteral wall thickness as a novel predictor for failed retrograde stent placement

Nick Dean1, Patrick Albers1, Sentil Senthilselvan3, Alexandra Bain1, Ryan McLarty1, Gillian Shiau2, Matthew Mancuso1, Tim Wollin1, Trevor D. Schuler1, Shubhadip (Shubha) K. De1.

1Department of Surgery, University of Alberta, Edmonton, AB, Canada; 2Radiology, University of Alberta, Edmonton, AB, Canada; 3Mathematics and Statistics, University of Alberta, Edmonton, AB, Canada

Introduction: Ureteric wall thickness (UWT) has been used to predict outcomes in shockwave lithotripsy, ureteroscopy, and spontaneous stone passage. Our purpose was to identify novel stone characteristics that can help predict failed retrograde ureteric stent placement in the setting of obstructing ureteric calculi.

Methods: We performed a retrospective case-control study including 34 patients who were identified to have failed urgent cystoscopic stent insertion and required nephrostomy tube insertion between 2013 and 2019. This group was compared to 75 consecutive patients in 2019 who underwent successful urgent retrograde stent placement for an obstructing ureteric calculi. All patients required a pre-decompression non-contrast CT (computed tomography) scan. Patient demographics and stone characteristics were collected from our electronic medical record and provincial wide imaging system. Statistical analysis was performed using univariate and multivariate logistic regression analysis in collaboration with a University affiliated statistician.

Results: On univariate analysis, non-septic indications for retrograde stent insertion, time since ureteral stone diagnosis, severe hydronephrosis, presence of renal atrophy, stone craniocaudal distance, stone circumference and ureteral wall thickness (Figure 1) were associated with failed retrograde stent placement. On multivariate analysis both a non-septic indication for stenting (OR 9.16, p=0.006) and UWT (OR 0.34, p=0.007) were found to be significantly associated with failed retrograde stent placement. A ROC analysis demonstrates an optimal UWT cut-off of 3.2 mm (Figure 2) with a sensitivity of 60.6% and specificity of 83.3% (Figure 3).

Conclusions: An elevated UWT and non-septic indication for urgent urinary decompression in the setting of obstructing ureteric stones are predictive of failed retrograde stent placement. These patients may benefit from upfront nephrostomy tube (NT) insertion.


© 2022 CUA 74th Annual Meeting