DISS vs FANS in Suction-Assisted RIRS for Medium-Sized Renal Stones

NCT07516535 | Not Yet Recruiting

• 1 other identifier: FMASU MS 142/2026
• Study Type: interventional
• Target: 126
• Locations: 1 country
• Sites: 1

Brief Summary

Kidney stones are a common health problem and may recur frequently, which can affect quality of life and kidney function. Retrograde intrarenal surgery (RIRS) is a minimally invasive treatment used for renal stones, but treatment of medium-sized stones may be associated with longer operative time, impaired visibility during surgery, residual stone fragments, and postoperative infectious complications caused by increased intrarenal pressure. Suction-assisted retrograde intrarenal surgery (RIRS) techniques have been developed to improve surgical efficiency and safety by facilitating continuous removal of stone fragments and helping control intrarenal pressure. Two commonly used suction-assisted approaches are direct in-scope suction (DISS) and flexible and navigable suction ureteric access sheath (FANS). However, there is limited prospective randomized evidence directly comparing these two techniques. This randomized prospective clinical study aims to compare direct in-scope suction (DISS) versus flexible and navigable suction ureteric access sheath (FANS) in adult patients with medium-sized renal stones measuring 2 to 3 cm who are undergoing retrograde intrarenal surgery (RIRS). Participants will be randomly assigned to one of the two suction-assisted techniques. The study will evaluate whether flexible and navigable suction ureteric access sheath (FANS) provides better outcomes than direct in-scope suction (DISS) in terms of stone-free rate and postoperative infection rate. The primary outcome is stone-free status assessed by postoperative imaging. Secondary outcomes include operative time, intraoperative visibility, and postoperative complications, particularly infection and urosepsis. The study hypothesis is that suction-assisted retrograde intrarenal surgery (RIRS) using the flexible and navigable suction ureteric access sheath (FANS) technique will result in a higher stone-free rate and a lower postoperative infection rate compared with direct in-scope suction (DISS) in the management of medium-sized renal stones.

Conditions

Kidney Stones; Nephrolithiasis; Renal Calculi

Keywords

Retrograde Intrarenal Surgery; Suction-Assisted Retrograde Intrarenal Surgery; Medium-Sized Renal Stones; Stone-Free Rate; Postoperative Infection; Urosepsis; Flexible Ureteroscopy; Holmium Laser Lithotripsy; Ureteric Access Sheath; Intrarenal Pressure

Outcome Measures

Primary Outcomes (1)

• Stone-Free Rate

  Stone-free status will be assessed by postoperative imaging using kidney, ureter, and bladder radiography and non-contrast computed tomography. Clinically insignificant residual fragments will be defined as residual fragments measuring 2 to 3 millimeters or less.

  At 1 month after surgery

Secondary Outcomes (4)

• Postoperative Infection Rate

  Within 1 month after surgery

• Operative Time

  During surgery (Intraoperatively)

• Intraoperative Visibility Score

  During surgery (Intraoperatively)

• Postoperative Complication Rate

  Within 1 month after surgery

Study Arms (2)

In-Scope Suction Group

EXPERIMENTAL

Participants assigned to this arm will undergo suction-assisted retrograde intrarenal surgery using direct in-scope suction. A single-use flexible ureteroscope with suction function will be used, and direct suction will be applied through the working channel during laser lithotripsy. Negative pressure will be maintained between 2 and 7 kilopascals and adjusted intraoperatively according to visibility and fragment evacuation. Laser lithotripsy will be performed using a holmium:yttrium-aluminum-garnet laser with dusting and popcorn techniques, followed by placement of a 6 French double-J ureteral stent.

Procedure: Direct In-Scope Suction

Flexible and Navigable Suction Ureteric Access Sheath Group

EXPERIMENTAL

Participants assigned to this arm will undergo suction-assisted retrograde intrarenal surgery using a flexible and navigable suction ureteric access sheath. The sheath will be inserted under guidewire guidance and connected to a vacuum device. Negative pressure will be maintained between 2 and 7 kilopascals and adjusted intraoperatively according to visibility and fragment evacuation. Laser lithotripsy will be performed using a holmium:yttrium-aluminum-garnet laser with dusting and popcorn techniques. Suction will be applied intermittently through the sheath to facilitate fragment evacuation, followed by placement of a 6 French double-J ureteral stent.

Procedure: Flexible and Navigable Suction Ureteric Access Sheath

Interventions

Direct In-Scope Suction PROCEDURE

Direct suction is applied through the working channel of the flexible ureteroscope during retrograde intrarenal surgery to facilitate evacuation of stone fragments and improve intraoperative visibility during laser lithotripsy.

Also known as: DISS

In-Scope Suction Group

Flexible and Navigable Suction Ureteric Access Sheath PROCEDURE

A flexible and navigable suction ureteric access sheath is used during retrograde intrarenal surgery to provide suction-assisted evacuation of stone fragments, improve visibility, and support intrarenal pressure control during laser lithotripsy.

Also known as: FANS

Flexible and Navigable Suction Ureteric Access Sheath Group

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Adults aged 18 to 60 years
• Radiologically confirmed renal stones measuring 2 to 3 centimeters
• Eligible for retrograde intrarenal surgery
• Normal renal function as evidenced by normal serum creatinine
• Able and willing to provide written informed consent

You may not qualify if:

• Pregnancy or lactation
• Active urinary tract infection at the time of enrollment
• Bleeding disorders or coagulopathies that contraindicate surgical intervention
• Anatomical malformations affecting the urinary tract
• Solitary kidney
• Inability or unwillingness to provide informed consent

Sponsors & Collaborators

• Ain Shams University: lead

Study Sites (1)

Ain Shams University Hospitals

Cairo, 11511, Egypt

Location

MeSH Terms

Conditions

Kidney Calculi; Nephrolithiasis

Condition Hierarchy (Ancestors)

Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Urolithiasis; Urinary Calculi; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Ahmed S Marey, MBBCh

CONTACT

01550199333; AhmedMarey@med.asu.edu.eg

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: This is an open-label surgical trial. The operating urologist cannot be masked because the two suction-assisted retrograde intrarenal surgery techniques require different instruments and procedural steps. Participants will undergo one assigned procedure according to the study protocol. Outcome assessment will be based on predefined clinical, laboratory, and imaging measures.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Resident of Urology

Model Details: Participants will be randomly assigned in parallel to one of two intervention arms. One arm will undergo suction-assisted retrograde intrarenal surgery using direct in-scope suction, and the other arm will undergo suction-assisted retrograde intrarenal surgery using flexible and navigable suction ureteric access sheath. Outcomes will be compared between the two groups in terms of stone-free rate, postoperative infection, operative time, intraoperative visibility, and complications.

Study Record Dates

• First Submitted: April 1, 2026
• First Posted: April 8, 2026
• Study Start: April 30, 2026
• Primary Completion (Estimated): April 30, 2027
• Study Completion (Estimated): April 30, 2027
• Last Updated: April 8, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: Data will become available beginning 6 months after publication of the main study results and will remain available for 5 years.
• Access Criteria: Data will be available to qualified researchers who provide a methodologically sound research proposal. Requests should be directed to the corresponding investigator. Access will be granted after review and approval of the proposal and execution of a data access agreement, with use limited to the purposes described in the approved proposal.

Locations

EG (1)