URSL Angle for Predicting Intraoperative Conversion

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Conditions studied: Ureteral Calculi

In brief

This international multicenter retrospective cohort study aims to externally validate the URSL Predictive Angle, a novel CT-derived morphometric parameter, as an imaging biomarker for predicting intraoperative conversion risk during transurethral ureteroscopic lithotripsy (URSL) for ureteral calculi. Intraoperative conversion is defined as the unanticipated abandonment of the planned endoscopic approach due to unfavorable ureteral anatomy or stone impaction, necessitating recourse to open ureterolithotomy, laparoscopic ureterolithotomy, or ureteral stent placement with planned staged secondary intervention. Such conversions are associated with protracted operative duration, heightened anesthetic exposure, and increased physical, psychological, and financial burdens on patients. The URSL Predictive Angle is a geometric parameter derived from preoperative coronal CT reformations that quantifies the degree of local ureteral angulation induced by an impacted calculus. Preliminary single-center data demonstrated robust predictive fidelity of this metric with an area under the ROC curve of 0.861 and an optimal discriminatory threshold of 131.8° yielding a sensitivity of 82% and a specificity of 88%. This study will enroll eligible patients from multiple domestic and international tertiary care hospitals who underwent URSL for ureteral calculi between January 1, 2018, and December 31, 2025. The primary outcome is intraoperative conversion of surgical approach. The predictive performance of the URSL angle will be evaluated using ROC curve analysis with AUC calculation. Propensity score matching and multivariable logistic regression will be employed to address potential confounding. This study is registered as a patient registry with a cohort model. Data collection is retrospective, involving abstraction from electronic medical records, operative logs, and PACS. A waiver of informed consent has been requested based on the retrospective design, minimal risk determination, stringent anonymization procedures, and impracticability of obtaining individual consent.

Key facts

Study ID

NCT07561684

Run by

The First Hospital of Jilin University

People needed

2200

Starts

2026-06-01

Expected to finish

2026-09-30

Last updated by the study team

2026-05-01

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Age > 18 years at the time of surgery, without restriction based on sex, ethnicity, or occupation.
• Preoperative imaging confirmation of unilateral, solitary, or unilateral multiple ureteral calculi. In cases of ipsilateral multiple stones, the calculus deemed primarily responsible for obstruction or designated as the principal surgical target shall serve as the index stone.
• Planned and attempted transurethral ureteroscopic lithotripsy as the initial treatment modality.
• Availability of preoperative thin-slice (section thickness ≤ 1.25 mm) computed tomography urography or non-contrast CT of the urinary tract in native Digital Imaging and Communications in Medicine (DICOM) format, of sufficient diagnostic quality to permit multiplanar reconstruction and precise morphometric analysis. Image data must be complete and free from substantial motion or beam-hardening artifact that would preclude accurate delineation of ureteral anatomy.

You may not qualify if…

• 1.Absence of preoperative CT imaging performed at the participating institution; missing, corrupted, or irretrievable DICOM data; or suboptimal image quality that precludes reliable ureteral segmentation and measurement.
• Incomplete inpatient medical records lacking essential demographic or baseline clinical data; operative notes containing insufficient procedural detail to definitively ascertain whether intraoperative conversion occurred or to adjudicate the specific etiology thereof.
• Prior ipsilateral percutaneous nephrostomy tube placement or ureteral stent indwelling for any indication before the index URSL procedure.
• Calculi situated at anatomically distinct locations, specifically the ureteropelvic junction or the ureteral orifice.
• Antecedent ipsilateral ureteral surgery (e.g., ureteral reimplantation, prior ureteroscopic lithotripsy) or history of urinary diversion (e.g., ileal conduit). Such patients are excluded because surgical alteration of native ureteral anatomy would confound the morphometric assumptions underlying URSL angle determination.

Full record on ClinicalTrials.gov

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