Long-term safety of UAS-assisted vs sheathless RIRS in adults with kidney stones

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a retrospective observational cohort study at Al-Azhar University Hospitals from 2020 to 2025, comparing patients who had a ureteral access sheath (UAS) used during their first RIRS to those who did not. Eligible adults with primary RIRS for renal stones ≤20 mm will be identified and invited for follow-up of at least 12 months. The main outcome is a composite of delayed ureteral stricture or new/progressive hydronephrosis on the operated side. Secondary outcomes include intraoperative ureteral injury, postoperative complications, stone-free rate, renal function, emergency visits, readmissions, and need for additional intervention. Analyses will use propensity scores and adjusted regression to minimize confounding from nonrandom treatment assignment.

Why it matters

Who can join: the full rules

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.

Where it's running

• Department of Urology, Al-Hussein and Sayed Galal University Hospitals, Al-Azhar University
  Cairo, Egypt Recruiting

Study contacts

• Principal investigator: Abul-fotouh Ahmed — Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
• Study coordinator: Abul-fotouh Ahmed
• Email: abulfotouhahmed@yahoo.com
• Phone: +201001066756

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.