An interventional study of Direct In-Scope Suction and Flexible and Navigable Suction Ureteric Access Sheath in Kidney Stones, Nephrolithiasis and Renal Calculi, sponsored by Ain Shams University. Not yet recruiting at 1 site in Egypt. Open to participants aged 18 Years to 60 Years. Per ClinicalTrials.gov, last updated 2026-10-23.
Sponsored by Ain Shams University · Not applicable, Interventional, and Treatment
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 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.
509 studies on the registry are indexed under Kidney Calculi; 146 are open to participants now.
This study's planned enrollment of 126 is above the median of 86 across 391 interventional studies indexed under Kidney Calculi.
Browse Kidney Calculi studies →Ain Shams University is the lead sponsor of 1,950 studies on the registry; 429 are open to participants now.
Of its 35 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
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The criteria were revised on the registry on Oct 23, 2026. See what changed
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
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
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
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.
Time frame: At 1 month after surgery
Postoperative Infection Rate
The proportion of participants who develop any postoperative infectious complications.
Time frame: Within 1 month after surgery
Operative Time
Operative time measured in minutes from ureteroscope insertion to successful placement of the double-J ureteral stent.
Time frame: 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.
Time frame: During surgery (Intraoperatively)
Postoperative Complication Rate
The proportion of participants with postoperative complications classified according to the Clavien-Dindo classification system.
Time frame: Within 1 month after surgery
Plan to share: 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.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
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.
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Apr 2027, 6 months later.
Of 183 non-industry interventional studies with no phase under Kidney Calculi, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 54. This study's planned 6 months is below that.
Counting every sponsor, half of 199 studies reached it within 26 months; a quarter within 12 and three quarters within 51.
Start moved once since we started tracking on Sep 25, 2026: Apr 2026 → Oct 2026, on Oct 23, 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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