CT-Based Predictor for the Success of 12/14-Fr Ureteral Access Sheath Placement

Abstract

Purpose. Ureteral access sheaths (UAS) are widely used in retrograde intrarenal surgery (RIRS), and this study aimed to develop a model for predicting the success of UAS placement based on computed tomography. Methods. We analyzed the clinical data of 847 patients who received ureteroscopy. Data on patient and stone characteristics and several computed tomography (CT)-based measurements were collected. A nomogram predicting the success of UAS placement was developed and validated using R software. Results. Two hundred and forty-seven patients were identified. Twenty-five patients (10.1%) failed to pass through the UAS. A model with three factors including the short diameter of ureteral calculi, the short diameter of hydronephrosis, and the diameter of the narrowest part of the renal parenchyma was to be strongly practical and had a high area under the curve on internal validation (80.3%). Using a threshold cutoff of 92%, the sensitivity and specificity for predicting UAS placement were 0.35 and 0.92, respectively. Conclusion. Our study provides a nomogram for predicting the success of UAS placement, and this model could help discriminate patients who are likely to suffer from failed UAS insertion; preoperative ureteral stenting is recommended according to the prediction.

A predictive model for the failure of the first placement of ureteral access sheath (12/14Fr): a multi-center retrospective study

“…Identifying patients with evaluated poor or excellent outcomes can guide them in choosing between ureteral stenting or fURS. Some researcher discovered that age, previous same-side procedures, and preoperative stent placement, sex, short medical history, short diameter of the ipsilateral common iliac artery, the shortest axis-base of hydronephrosis, the narrowest thickness of the renal parenchyma, and the narrowest calculus small diameter are signi cant risk factors for the failure of 12/14Fr UAS placement [3,6,7]. Moreover, recently a study revealed that the risk of ureteral injury after UAS (12/14Fr) insertion could be predicted by measuring the inner diameter of the upper ureter [8].…”