Secondary signs combined with renal pelvis urine density on preoperative CT as a predictor of infection following ureteroscopic lithotripsy with chronic kidney disease.

Purpose: Retrospective studies have explored the association between computed tomography (CT)-derived secondary signs and renal pelvic urine density (RPUD) with postoperative infection after ureteroscopic lithotripsy (URSL). This study evaluated the prognostic value of these indicators in chronic kidney disease (CKD) patients. Material and methods: Clinical data of patients undergoing URSL for ureteral calculi at two tertiary hospitals from June 2015 to June 2025 were retrospectively collected. Patients were categorized into infection and non-infection groups. Baseline demographics, stone characteristics, RPUD, perinephric fat stranding (PFS), tissue rim sign (TRS), CKD history, and intraoperative variables were compared. Independent predictors were identified via multivariate logistic regression, and a nomogram was constructed. Results: Postoperative infection occurred in 102 patients (12.6%). The infection group had significantly higher rates of positive preoperative urine culture, diabetes, larger stone diameter, longer operation time, advanced CKD stage, elevated RPUD, and increased incidence of PFS and TRS (all Conclusions: Elevated RPUD combined with positive CT secondary signs (PFS and TRS) is significantly associated with postoperative infection risk in CKD patients undergoing URSL. These easily obtainable non-contrast computed tomography-derived markers offer a novel and practical approach for preoperative risk stratification, enabling individualized preventive strategies and surgical optimization in this high-risk population.