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

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
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

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 10, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 23, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 30, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 30, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 23, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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.

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