FANS VS DISS in Treatment of Renal Stone < 2cm

April 23, 2026 updated by: Armia Ezzat Thabet Azer, Assiut University

Flexible and Navigable Access Sheath (FANS) VS Direct in Scope Suction (DISS) in Treatment of Renal Stone > 2 cm , Controlled Randomized Trial

To compare between FANS & DISS in :

  • Operative time
  • Stone free rate
  • Complications
  • Amount of fluid irrigation

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Retrograde intrarenal surgery (RIRS) has revolutionized the management of renal stones, yet achieving high stone-free rates (SFR) while maintaining low intrarenal pressure (IRP) remains a challenge. Elevated IRP during irrigation is linked to post-operative complications, including systemic inflammatory response syndrome and renal parenchymal damage. To mitigate these risks, suction-assisted technologies have emerged as vital adjuncts to traditional flexible ureteroscopy (FURS).The Flexible and Navigable Access Sheath (FANS) represents a significant evolution in this field. Unlike traditional rigid sheaths, FANS features a deflectable tip that can be guided into specific calyces, allowing for synchronized suction and active fragment evacuation. Conversely, Direct In-Scope Suction (DISS) utilizes a sheathless approach, where suction is integrated directly into the ureteroscope. While DISS avoids potential ureteral trauma associated with access sheaths, FANS is often associated with shorter operative times due to its superior irrigation-aspiration efficiency.For renal stones measuring less than 2 cm, both techniques aim to optimize the "perfusion-absorption" balance, effectively clearing stone dust and debris while preventing pyelovenous reflux. However, comparative data specifically for smaller stones remains limited. This study evaluates the clinical efficacy, safety profiles, and operative outcomes of FANS versus DISS in the treatment of renal calculi < 2 cm, aiming to determine which suction modality provides the most favorable balance of procedural efficiency and patient safety.

Study Type

Interventional

Enrollment (Estimated)

100

Phase

  • Not Applicable

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • All patients < 18 years old presented with renal stone > 2cm whatever the site of the stone (pelvic or calyceal)

Exclusion Criteria:

  • Inaccessibility to introduce access sheath or FURS
  • Previous Inserted JJ stent
  • Active UTI
  • Patients refuse to participate in the protocol

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Flexible and navigable access sheath (FANS)
In patients undergoing the FANS procedure , an access sheath with a bendable tip and aspiration feature will be placed into the relevant ureter up to the renal pelvis over the guidewire. The single-use flexible scope will be passed through the access sheath, and the renal collecting system. After this maneuver, the tip of the placed access sheath will be pushed into the renal calyces or pelvis under the guidance of the flexible URS and a holmium fiber will be used to pulverize the stones with a 273-µm fiber. In this group, stones were disintegrated (fragmented) into an adequate size (< 3 mm) to allow an efficient extraction with the help of active aspiration, finished by insertion of JJ in all patients.
Procedure: Flexible ureteroscopy
Unlike traditional rigid sheaths, FANS features a deflectable tip that can be guided into specific calyces, allowing for synchronized suction and active fragment evacuation. Conversely, Direct In-Scope Suction (DISS) utilizes a sheathless approach, where suction is integrated directly into the ureteroscope. While DISS avoids potential ureteral trauma associated with access sheaths, FANS is often associated with shorter operative times due to its superior irrigation-aspiration efficiency
Other Names:
  • FURS
Experimental: Direct in scope suction (DISS)
In the DISS group, a single-use flexible URS with a direct in-scope suction system will be introduced over the placed guidewire and navigated into the renal pelvis without the use of an access sheath. The suctioning port on the ureteroscope and the laser fiber operates via the same port. In this group, the dusting preset of the same laser device will be used to disintegrate the stones. While continuous irrigation was applied to ensure optimum visualization, finished by insertion of JJ in all patients
Procedure: Flexible ureteroscopy
Unlike traditional rigid sheaths, FANS features a deflectable tip that can be guided into specific calyces, allowing for synchronized suction and active fragment evacuation. Conversely, Direct In-Scope Suction (DISS) utilizes a sheathless approach, where suction is integrated directly into the ureteroscope. While DISS avoids potential ureteral trauma associated with access sheaths, FANS is often associated with shorter operative times due to its superior irrigation-aspiration efficiency
Other Names:
  • FURS

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Operative time
Time Frame: <60 minutes
The operative time is the duration of surgical procedure
<60 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Assiut University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

September 1, 2027

Study Registration Dates

First Submitted

April 10, 2026

First Submitted That Met QC Criteria

April 23, 2026

First Posted (Actual)

April 30, 2026

Study Record Updates

Last Update Posted (Actual)

April 30, 2026

Last Update Submitted That Met QC Criteria

April 23, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FANS VS DISS

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Renal Calculi

Clinical Trials on Flexible ureteroscopy

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Bosnia & Herzegovina

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe