Safety and Efficacy of Traditional Versus Flexible and Navigable Suction Sheath in Retrograde Intra-Renal Stone Surgery

Safety and Efficacy of Using Traditional Ureteral Access Sheath Versus Flexible and Navigable Suction Sheath in Retrograde Intra-Renal Stone Surgery for Renal Stones ≤ 20 mm: A Randomized Controlled Study

This study compares two techniques used during RIRS for the treatment of kidney stones measuring up to 20 mm. During RIRS, surgeons often use a device called a UAS to help pass instruments into the urinary system and to assist with the removal of stone fragments. A traditional UAS allows irrigation fluid and small fragments to flow out passively. A newer type, known as a suction UAS, applies controlled negative pressure to help clear stone fragments more effectively and may reduce pressure inside the kidney during the procedure.

The purpose of this study is to determine whether the suction UAS offers better clinical outcomes than the traditional UAS. The main outcomes assessed include the SFR, the duration of surgery, and complications after the procedure such as fever, sepsis, urinary infection, calyceal injury, or ureteral injury.

In this randomized study, adult patients undergoing RIRS for a single renal stone were assigned to either the suction UAS or the traditional UAS. All patients were followed after surgery to assess stone clearance and any complications. The results of this study aim to provide evidence on whether suction UAS improves safety or effectiveness in RIRS compared with the traditional approach.

Study Overview

• Status: Completed
• Conditions: Kidney Calculi; Nephrolithiasis; Urolithiasis
• Intervention / Treatment: Procedure: Retrograde intrarenal surgery using a ureteral access sheath with suction; Procedure: Retrograde intrarenal surgery using a traditional ureteral access sheath

• Study Type: Interventional
• Enrollment (Actual): 140
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo Governorate
    • Cairo, Cairo Governorate, Egypt, 11511
      • Ain Shams University Hospitals, Department of Urology

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged eighteen years or older
• Male or female participants
• Presence of a single kidney stone measuring up to twenty millimeters
• Candidate for retrograde intrarenal surgery according to clinical evaluation
• Able and willing to provide informed consent

Exclusion Criteria:

• Active or untreated urinary infection
• History of open kidney surgery or kidney trauma
• Contraindications to anesthesia, including uncontrolled diabetes, severe cardiac disease, or significant coagulation disorders
• Presence of ureteral narrowing or obstruction at the junction between the ureter and the kidney
• Positive urine culture that does not resolve after appropriate treatment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Suction Ureteral Access Sheath Group; Participants in this group underwent retrograde intrarenal surgery using a ureteral access sheath equipped with a suction mechanism. After anesthesia, a guide wire was placed and the ureter was evaluated. The suction ureteral access sheath was inserted over the guide wire and positioned inside the kidney near the stone. Controlled negative pressure was applied to improve removal of stone fragments and to maintain lower pressure inside the kidney during the procedure. Laser lithotripsy was performed, and stone fragments were aspirated through the suction system. A double-J ureteral stent was placed at the end of the procedure.	Procedure: Retrograde intrarenal surgery using a ureteral access sheath with suction; This intervention involves performing retrograde intrarenal surgery using a ureteral access sheath equipped with a suction mechanism that applies controlled negative pressure to help remove stone fragments and manage pressure inside the kidney during the procedure.
Active Comparator: Traditional Ureteral Access Sheath Group; Participants in this group underwent retrograde intrarenal surgery using a traditional ureteral access sheath without suction. After anesthesia and guide wire placement, the traditional ureteral access sheath was inserted and positioned below the junction between the ureter and the kidney. Laser lithotripsy was performed in the standard manner. Stone fragments were removed passively using irrigation and by repeatedly retrieving fragments with a basket. A double-J ureteral stent was placed at the end of the procedure.	Procedure: Retrograde intrarenal surgery using a traditional ureteral access sheath; This intervention involves performing retrograde intrarenal surgery using a conventional ureteral access sheath without suction, relying on irrigation flow and basket retrieval for stone fragment removal.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Stone-free rate	The stone-free rate represents the proportion of participants who show no residual stone fragments or only clinically insignificant small fragments on postoperative imaging. Imaging is performed using non-contrast computed tomography. Findings are classified into four categories based on fragment size: complete clearance, fragments up to two millimeters, fragments between two point one and four millimeters, and fragments larger than four millimeters. The outcome is expressed as the percentage of participants achieving complete clearance or clinically insignificant fragments.	One month after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of surgery	Total time required to complete the surgical procedure, measured from the insertion of the ureteroscope until placement of the ureteral stent.	During surgery
Readmission after surgery	Number of participants requiring hospital readmission for pain, infection, or any complication related to the surgery.	Within one month after surgery
Need for an additional procedure	Proportion of participants requiring a second surgical intervention to remove remaining stone material.	Within three months after surgery
Urinary infection after surgery	Occurrence of laboratory-confirmed urinary infection requiring medical treatment, classified using the Clavien-Dindo system.	Within one month after surgery
Systemic infection after surgery	Occurrence of systemic infection requiring medical intervention, including antibiotic therapy or hospitalization, assessed using the Clavien-Dindo classification.	Within one month after surgery

Collaborators and Investigators

• Sponsor: Ain Shams University

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2025
• Primary Completion (Actual): December 1, 2025
• Study Completion (Actual): December 1, 2025

Study Registration Dates

• First Submitted: December 3, 2025
• First Submitted That Met QC Criteria: December 3, 2025
• First Posted (Actual): December 16, 2025

Study Record Updates

• Last Update Posted (Actual): February 11, 2026
• Last Update Submitted That Met QC Criteria: February 8, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Urolithiasis; RIRS; Kidney Calculi; Endourology; Laser Lithotripsy; UAS; Suction UAS; Stone-Free Rate
• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urinary Calculi; Pathological Conditions, Signs and Symptoms; Kidney Calculi; Nephrolithiasis; Urolithiasis; Surgical Procedures, Operative; Drainage; Suction
• Other Study ID Numbers: FMASU_MS401_2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data collected during the study will be made available after removal of all direct identifiers. The shared data will include demographic information, clinical characteristics, surgical details, and outcome measurements related to stone clearance and postoperative events. Data will be provided only for the purpose of scientific research and verification of study findings.
• IPD Sharing Time Frame: Data will be available starting six months after publication of the main study results. The data will remain accessible for a period of five years from the date of release.
• IPD Sharing Access Criteria: Researchers who wish to access the data must submit a written request that includes a summary of the research objectives and the intended use of the data. Approval will require review by the study investigators. Upon approval, data will be shared through a secure data transfer method. Recipients must agree not to attempt to reidentify participants and must use the data only for the approved research purpose.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No