Kidney StonesNCT07516535
DISS vs FANS in Suction-Assisted RIRS for Medium-Sized Renal Stones
A study testing Direct In-Scope Suction and Flexible and Navigable Suction Ureteric Access Sheath in people with Kidney Stones and Nephrolithiasis, run by Ain Shams University at 1 site in Egypt.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 to 60 years
- Conditions the study is for
- Kidney Stones, Nephrolithiasis, Renal Calculi
- What is being tested?
- Direct In-Scope Suction and Flexible and Navigable Suction Ureteric Access Sheath
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 126 participants
- Where
- 1 siteEgypt
- Study dates
- 30 Oct 2026to 30 Apr 2027
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Adults aged 18 to 60 years
- Radiologically confirmed renal stones measuring 1 to 2 centimeters
- Eligible for retrograde intrarenal surgery
- Normal renal function as evidenced by normal serum creatinine
- Able and willing to provide written informed consent
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Official title: The Impact of Suction-Assisted RIRS (DISS Versus FANS) on Postoperative Infection Rate and Stone-Free Rate After Treatment of Medium Sized Renal Stones
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.
Read more
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 1 to 2 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
- Being tested
- Direct In-Scope Suction, Flexible and Navigable Suction Ureteric Access Sheath
- 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
- Medical subject headings
- Kidney Calculi, Nephrolithiasis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Direct In-Scope SuctionProcedure or surgery
Also called DISS
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.
Flexible and Navigable Suction Ureteric Access SheathProcedure or surgery
Also called FANS
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Procedure: Flexible and Navigable Suction Ureteric Access Sheath |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: At 1 month after surgery
Secondary outcomes (4)
Postoperative Infection Rate
The proportion of participants who develop any postoperative infectious complications.
Measured: Within 1 month after surgery
Operative Time
Operative time measured in minutes from ureteroscope insertion to successful placement of the double-J ureteral stent.
Measured: During surgery (Intraoperatively)
Intraoperative Visibility Score
Intraoperative visibility will be graded by the operating surgeon using a 3-point scale: grade 0 for poor visibility, grade 1 for moderate visibility, and grade 2 for good visibility.
Measured: During surgery (Intraoperatively)
Postoperative Complication Rate
The proportion of participants with postoperative complications classified according to the Clavien-Dindo classification system.
Measured: Within 1 month after surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Apr 2026
- Study start30 Oct 2026 (estimated)
- Primary completion30 Apr 2027 (estimated)
- Study completion30 Apr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Kidney StonesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- 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.
- Masking
- None (open label)
- Enrolment
- 126 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ain Shams University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ahmed Samy Abd Elmawgod Ali Marey, Ain Shams University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07516535
- Sponsor's protocol ID
- FMASU MS 142/2026
- Status last verified
- Oct 2026
- First submitted
- 1 Apr 2026
- Last updated
- 23 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified individual participant data underlying the results reported in this study will be made available, including demographic data, baseline characteristics, intervention allocation, outcome measures, and adverse event data.