Flexible and Navigable Suction Ureteral Access Sheath (FANS) vs Conventional Access Sheaths in RIRS: A Prospective Randomized Study.

Comparative Study of Access Sheaths With Flexible Tips and Suction Versus Conventional Access in Endourology: A Prospective Study

Kidney stones located in the kidney are commonly treated using a minimally invasive procedure called retrograde intrarenal surgery (RIRS). During this procedure, a ureteral access sheath is often used to facilitate repeated access to the kidney, improve visualization, and allow irrigation fluid to drain.

Newer access sheaths have been developed with flexible distal tips and built-in suction capabilities, which may help reduce operative time by improving visibility and removing stone fragments and irrigation fluid more efficiently.

This prospective randomized study compared a flexible and navigable suction ureteral access sheath with a conventional ureteral access sheath in adult patients undergoing RIRS for kidney stones measuring 10 mm or larger. Participants were randomly assigned to one of the two access sheath types.

The primary objective of the study was to evaluate whether the use of a suction-enabled access sheath reduces operative time. Secondary objectives included assessment of complications, length of hospital stay, stone-free rate, and need for additional interventions.

Study Overview

• Status: Completed
• Conditions: Nephrolithiasis; Kidney Stones
• Intervention / Treatment: Device: Flexible and Navigable Suction Ureteral Access Sheath (FANS); Device: Conventional Ureteral Access Sheath

Detailed Description

This was a prospective, single-center, randomized controlled trial conducted at a tertiary referral endourology center. Adult patients (≥18 years) with renal stones measuring 10 mm or greater and scheduled to undergo retrograde intrarenal surgery (RIRS) under general anesthesia were eligible for inclusion.

Participants were randomized in a 1:1 ratio to undergo RIRS using either a flexible and navigable suction ureteral access sheath (FANS group) or a conventional ureteral access sheath (control group). Randomization was performed using a computer-generated sequence with allocation concealment via sealed opaque envelopes. Blinding of the operating surgeon was not feasible due to the nature of the devices used.

All procedures were performed by experienced endourologists using standardized surgical techniques. Flexible ureteroscopy was performed with a digital ureteroscope, and stone fragmentation was achieved using a Holmium:YAG laser in dusting mode. In the suction access sheath group, negative pressure suction was applied through the sheath according to manufacturer guidelines. Irrigation parameters were standardized across both study arms.

The primary outcome measure was operative time, defined as the interval from insertion of the first endoscopic instrument through the urethra to removal of the final instrument at the end of the procedure. Secondary outcome measures included intraoperative and postoperative complications (classified using the Clavien-Dindo system), ureteral wall injury, length of hospital stay, stone migration, and stone-free rate. Stone-free status was defined as the absence of residual fragments greater than 2 mm on postoperative imaging.

Preoperative assessment included non-contrast computed tomography to evaluate stone size, location, and burden. Postoperative imaging was performed using kidney-ureter-bladder radiography or renal ultrasound approximately two weeks after surgery.

The study was approved by the Institutional Review Board of Barzilai University Medical Center, and all participants provided written informed consent prior to enrollment.

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Israel
  • Ashkelon, Israel, 7830604
    • Barzilai University Medical Center

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

Age 18 years or older

Presence of single or multiple renal stones measuring 10 mm or greater

Eligible for retrograde intrarenal surgery under general anesthesia

Ability to provide written informed consent

Exclusion Criteria:

Pregnancy

Active urinary tract infection at the time of surgery

Known bleeding disorders

Solitary kidney

Anatomical abnormalities of the urinary tract that could affect ureteroscopic access

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: Flexible and Navigable Suction Ureteral Access Sheath (FANS); Participants underwent retrograde intrarenal surgery using a flexible and navigable ureteral access sheath with integrated suction capability.	Device: Flexible and Navigable Suction Ureteral Access Sheath (FANS); Use of a flexible distal-tip ureteral access sheath with integrated suction during retrograde intrarenal surgery to facilitate access, irrigation control, and fragment evacuation.
Active Comparator: Conventional Ureteral Access Sheath; Participants underwent retrograde intrarenal surgery using a standard, non-suction ureteral access sheath.	Device: Conventional Ureteral Access Sheath; Use of a standard ureteral access sheath without suction during retrograde intrarenal surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Operative Time	Operative time was defined as the duration from insertion of the first endoscopic instrument through the urethra to removal of the final instrument at the end of the procedure.	During the surgical procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intraoperative and Postoperative Complications	Intraoperative and postoperative complications were recorded and classified according to the Clavien-Dindo classification system.	Perioperative period (Day of surgery through postoperative Day 30).
Stone-Free Rate	Stone-free status was defined as the absence of residual stone fragments greater than 2 mm on postoperative imaging.	Two weeks after surgery
Length of Hospital Stay	Length of hospital stay was defined as the number of days from surgery to hospital discharge.	From end of surgery until hospital discharge (typically 1-3 days).
Ureteral Wall Injury	Ureteral wall injury was assessed intraoperatively and classified according to the Traxer-Thomas classification system.	During the surgical procedure

Collaborators and Investigators

• Sponsor: Barzilai Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2024
• Primary Completion (Actual): November 1, 2024
• Study Completion (Actual): November 30, 2024

Study Registration Dates

• First Submitted: January 7, 2026
• First Submitted That Met QC Criteria: January 26, 2026
• First Posted (Actual): January 30, 2026

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: February 5, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: RIRS; Operative Time; Retrograde Intrarenal Surgery; Endourology; Ureteral Access Sheath; Suction Ureteral Access Sheath; Flexible Tip Ureteral Access Sheath
• 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; Urolithiasis; Urinary Calculi; Pathological Conditions, Signs and Symptoms; Kidney Calculi; Nephrolithiasis
• Other Study ID Numbers: 0069-24-BRZ

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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