This retrospective comparative cohort study will include adult patients who underwent primary RIRS for renal stones ≤20 mm at Al-Azhar University Hospitals between January 2020 and December 2025. Patients will be classified by whether a ureteral access sheath (UAS) was used during the index RIRS, and all eligible patients will be invited for active long-term follow-up (minimum 12 months) to assess the composite outcome of delayed ipsilateral ureteral stricture or new/progressive ipsilateral hydronephrosis and other safety and efficacy outcomes. Propensity-score methods and adjusted regression analyses will be used to control confounding.
Age ≥18 years at time of index RIRS.
Primary RIRS performed at Al-Azhar University Hospitals between Jan 1, 2020 and Dec 31, 2025.
Renal stone(s) with maximum diameter ≤20 mm on preoperative imaging.
No ipsilateral ureteral stent or nephrostomy before index RIRS.
Primary ureteral stone treated during the same procedure.
Staghorn or >20 mm stone burden.
Prior ipsilateral ureteral stricture or reconstructive surgery.
Congenital renal/ureteral anomalies affecting outcome (e.g., horseshoe kidney, duplicated system).