Long-term Safety of UAS-assisted vs Sheathless RIRS in Non-prestented Patients

Long-Term Safety Outcomes of Ureteral Access Sheath-Assisted Versus Sheathless Retrograde Intrarenal Surgery for Renal Stones ≤20 mm in Non-Prestented Patients: A Retrospective Comparative Cohort Study With Active Follow-up

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.

Inclusion Criteria:

• 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.
• Documented operative record specifying whether a UAS was used.
• At least 12 months elapsed since index RIRS.
• Available contact information allowing invitation for active follow-up.

Exclusion Criteria:

• 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).
• Incomplete operative or preoperative imaging records that preclude determination of eligibility or exposure (UAS use).
• Additional ipsilateral ureteral procedure during follow-up that independently causes ureteral narrowing.
• Refusal to participate in active follow-up or failure to attend after repeated attempts.