URSL Angle for Predicting Intraoperative Conversion

NCT07561684 | Not Yet Recruiting

• 1 other identifier: JLU-Wyb
• Study Type: observational
• Target: 2,200
• Locations: 0 countries
• Sites: N/A

Brief Summary

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.

Conditions

Ureteral Calculi

Outcome Measures

Primary Outcomes (1)

• Intraoperative Conversion of Surgical Approach

  Unanticipated abandonment of the planned transurethral ureteroscopic lithotripsy procedure due to technical impediments directly attributable to unfavorable ureteral anatomy or calculus impaction, necessitating intraoperative recourse to an alternative surgical modality. Alternative modalities include open ureterolithotomy, laparoscopic ureterolithotomy, or ureteral stent placement with planned staged secondary intervention. Conversions due to equipment malfunction, hemodynamic instability, or other non-anatomic etiologies are excluded. Outcome will be ascertained by retrospective review of operative records.

  At the time of surgery, as documented in the operative record

Study Arms (2)

Success Group

Patients who successfully underwent transurethral ureteroscopic lithotripsy without intraoperative conversion, defined as successful endoscope advancement to the target calculus, completion of lithotripsy and stone extraction, and no deviation from the planned surgical approach due to ureteral conditions or stone characteristics.

Conversion Group

Patients who experienced intraoperative conversion from transurethral ureteroscopic lithotripsy to an alternative surgical modality due to technical impediments attributable to unfavorable ureteral anatomy or stone impaction. Alternative modalities include open ureterolithotomy, laparoscopic ureterolithotomy, or ureteral stent placement with planned staged secondary intervention.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

All participating centers are required to maintain established expertise in ureteroscopic surgical techniques, robust clinical data management infrastructure, and comprehensive archival systems for preoperative computed tomography imaging. Each center shall formally assent to and comply with the unified study protocol, thereby ensuring data completeness, source traceability, and adherence to international ethical standards. Eligible patient records will be retrieved for the period spanning January 1, 2018, to December 31, 2025 (inclusive, encompassing an eight-year interval). All patients who underwent URSL for ureteral calculi and satisfied the stipulated eligibility criteria during this timeframe will be considered for inclusion.

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:

• 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.

Sponsors & Collaborators

• The First Hospital of Jilin University: lead

Related Publications (4)

• Brisbane W, Bailey MR, Sorensen MD. An overview of kidney stone imaging techniques. Nat Rev Urol. 2016 Nov;13(11):654-662. doi: 10.1038/nrurol.2016.154. Epub 2016 Aug 31.

  PMID: 27578040 BACKGROUND

• Li Y, Chen Y, Liu X, Chen J, Gan T, Zhang H. Patient Pain and Function After Correction of Posterior Malleolar Malunion. Foot Ankle Int. 2021 Dec;42(12):1536-1546. doi: 10.1177/10711007211017831. Epub 2021 Jul 1.

  PMID: 34210180 BACKGROUND

• Turk C, Petrik A, Sarica K, Seitz C, Skolarikos A, Straub M, Knoll T. EAU Guidelines on Interventional Treatment for Urolithiasis. Eur Urol. 2016 Mar;69(3):475-82. doi: 10.1016/j.eururo.2015.07.041. Epub 2015 Sep 4.

  PMID: 26344917 BACKGROUND

• Okada Y, Kohara K, Ochi M, Nagai T, Tabara Y, Igase M, Miki T. Mechanical stresses, arterial stiffness, and brain small vessel diseases: Shimanami Health Promoting Program Study. Stroke. 2014 Nov;45(11):3287-92. doi: 10.1161/STROKEAHA.114.006539. Epub 2014 Sep 16.

  PMID: 25228261 BACKGROUND

MeSH Terms

Conditions

Ureteral Calculi

Condition Hierarchy (Ancestors)

Ureterolithiasis; Ureteral Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Urolithiasis; Urinary Calculi; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Yanbo Wang

CONTACT

13756469518; wangyanb@jlu.edu.cn

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 24, 2026
• First Posted: May 1, 2026
• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): September 30, 2026
• Last Updated: May 1, 2026

Record last verified: 2026-01