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

NCT07767773 | Recruiting

• 1 other identifier: UroAzhar_15_026
• Study Type: observational
• Target: 1,200
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Renal Stone Disease; Ureteral Stricture; Hydronephrosis; Urolithiasis; Retrograde Intrarenal Surgery; Ureteral Access Sheath

Outcome Measures

Primary Outcomes (1)

• Composite outcome: delayed ipsilateral ureteral stricture or new/progressive ipsilateral hydronephrosis.

  Incidence of the composite primary outcome consisting of either delayed ipsilateral ureteral stricture or new/progressive ipsilateral hydronephrosis after retrograde intrarenal surgery (RIRS). Delayed ureteral stricture will be defined by imaging or functional evidence of treated-ureter narrowing, including CT urography, retrograde pyelography, diagnostic ureteroscopy, diuretic renography, persistent/progressive upper-tract obstruction, or need for therapeutic intervention such as ureteral stenting, balloon dilation, endoureterotomy, or reconstructive surgery. New/progressive hydronephrosis will be defined as hydronephrosis absent preoperatively or increased in severity after RIRS, not explained by residual or recurrent stone disease or another non-study cause.

  At least 12 months after the index RIRS procedure

Secondary Outcomes (6)

• Intraoperative ureteral injury

  During the index RIRS procedure

• Stone-free rate

  4 to 12 weeks after the index RIRS procedure

• Postoperative infectious complications

  From surgery to 30 days after surgery, and during long-term follow-up up to 12 months

• Change in serum creatinine

  Baseline and 12 months after the index RIRS procedure

• Change in estimated glomerular filtration rate

  Baseline and 12 months after the index RIRS procedure

Study Arms (2)

UAS-assisted RIRS cohort.

Adult patients with renal stones ≤20 mm who underwent primary retrograde intrarenal surgery using a ureteral access sheath and had no preoperative ipsilateral ureteral stent or nephrostomy.

Procedure: Ureteral access sheath-assisted RIRS

Sheathless RIRS cohort.

Adult patients with renal stones ≤20 mm who underwent primary retrograde intrarenal surgery without a ureteral access sheath and had no preoperative ipsilateral ureteral stent or nephrostomy.

Procedure: Sheathless RIRS

Interventions

Ureteral access sheath-assisted RIRS PROCEDURE

Retrograde intrarenal surgery (RIRS) performed with placement of a ureteral access sheath during the initial procedure. Details recorded: sheath diameter (Fr), length, manufacturer/model, insertion success, number of insertion attempts, need for ureteral dilation, intraoperative findings.

UAS-assisted RIRS cohort.

Sheathless RIRS PROCEDURE

RIRS performed without placement of a ureteral access sheath. Details recorded: guidewire use, ureteral dilation, access difficulty, intraoperative findings.

Sheathless RIRS cohort.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adult patients (≥18 years) who underwent primary RIRS for renal stones ≤20 mm without ipsilateral preoperative ureteral stenting or nephrostomy at Al-Azhar University Hospitals between Jan 1, 2020 and Dec 31, 2025; active follow-up performed ≥12 months after index procedure.

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Al-Azhar University: lead

Study Sites (1)

Department of Urology, Al-Hussein and Sayed Galal University Hospitals, Al-Azhar University

Cairo, Egypt

RECRUITING

MeSH Terms

Conditions

Hydronephrosis; Urolithiasis

Condition Hierarchy (Ancestors)

Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases

Study Officials

• Abul-fotouh Ahmed

  Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Abul-fotouh Ahmed

CONTACT

+201001066756; abulfotouhahmed@yahoo.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Urology

Study Record Dates

• First Submitted: August 11, 2026
• First Posted: August 17, 2026
• Study Start: August 16, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 25, 2027
• Last Updated: August 18, 2026

Record last verified: 2026-08

Locations

EG (1)