New CT angle may predict kidney stone surgery complications

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age \> 18 years at the time of surgery, without restriction based on sex, ethnicity, or occupation. 2. 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. 3. Planned and attempted transurethral ureteroscopic lithotripsy as the initial treatment modality. 4. 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. Exclusion Criteria: * 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. 2.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. 3.Prior ipsilateral percutaneous nephrostomy tube placement or ureteral stent indwelling for any indication before the index URSL procedure. 4.Calculi situated at anatomically distinct locations, specifically the ureteropelvic junction or the ureteral orifice. 5.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.