Renal CalculiNCT07773090
Role of Pre-stenting Before Retrograde Intrarenal Surgery With Miniaturized Flexible Ureteroscopes
A study testing Preoperative double-J ureteral stenting followed by retrograde intrarenal surgery and Direct retrograde intrarenal surgery without planned preoperative ureteral stenting in people with Renal Calculi, run by Al-Azhar University at 1 site in Egypt.
Trial summary
This prospective randomized controlled trial will compare retrograde intrarenal surgery performed after routine preoperative ureteral stenting with direct retrograde intrarenal surgery without planned preoperative stenting in adults with unilateral renal calculi measuring 10-20 mm. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Renal Calculi
- What is being tested?
- Preoperative double-J ureteral stenting followed by retrograde intrarenal surgery and Direct retrograde intrarenal surgery without planned preoperative ureteral stenting
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 270 participants
- Where
- 1 siteEgypt
- Study dates
- 19 Aug 2026to 1 Nov 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Participants must meet all of the following criteria:
- Adults aged 18-70 years.
- Unilateral renal calculi.
- Maximum total renal stone burden of 10-20 mm.
- Planned treatment with RIRS.
- Suitable candidate for elective endoscopic stone treatment.
Show all 9Show fewer
- Negative or appropriately treated preoperative urine culture.
- Ability to provide written informed consent.
- Ability and willingness to comply with postoperative follow-up, including non-contrast CT at 4 weeks after the final RIRS procedure.
Who cannot join
- Participants will be excluded for any of the following:
- Bilateral renal calculi requiring simultaneous surgical treatment.
- Active urinary tract infection, sepsis, or infected obstruction requiring urgent drainage.
- Solitary kidney when randomization is considered clinically unsafe.
- Known ureteral stricture or congenital ureteral abnormality likely to interfere with ureteroscopic access.
- Previous failed ipsilateral ureteroscopic access requiring clinically indicated pre-stenting.
Show all 16Show fewer
- Existing ipsilateral ureteral stent or nephrostomy.
- Previous ureteral reconstruction or urinary diversion.
- Total renal stone burden greater than 20 mm.
- Staghorn calculi.
- Uncorrected coagulopathy.
- Pregnancy.
- Severe uncorrected cardiopulmonary disease precluding anesthesia.
- Inability or unwillingness to provide informed consent.
- Inability or unwillingness to comply with follow-up.
- Any other condition judged by the treating surgeon to make randomization or RIRS clinically inappropriate or unsafe.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Egypt1 site, 1 recruiting
- Recruiting
Department of Urology, Al-Hussein and Sayed Galal University Hospitals, Al-Azhar University
Cairo
Abul-fotouh Ahmed, +201001066756, abulfotouhahmed@yahoo.com
About this study
Official title: Does Pre-stenting Still Have a Role in Retrograde Intrarenal Surgery in the Era of Miniaturized Flexible Ureteroscopes? Surgical Outcomes From a Prospective Randomized Controlled Trial
This prospective randomized controlled trial will compare retrograde intrarenal surgery performed after routine preoperative ureteral stenting with direct retrograde intrarenal surgery without planned preoperative stenting in adults with unilateral renal calculi measuring 10-20 mm. The study will evaluate stone-free rate, ureteral access, need for rescue stenting, operative outcomes, complications, staged procedures, postoperative recovery, and auxiliary treatment.
Read the detailed description
Retrograde intrarenal surgery is widely used for the treatment of selected renal calculi. Miniaturized flexible ureteroscopes may facilitate direct ureteral and renal access, potentially reducing the need for routine preoperative ureteral stenting. However, pre-stenting may improve passive ureteral dilation, facilitate access, reduce failed access, and decrease the need for staged treatment.
Participants will be randomly assigned in a 1:1 ratio to either preoperative double-J ureteral stenting for 7-14 days followed by RIRS or direct RIRS without planned preoperative ureteral stenting. All procedures will use a standardized miniaturized digital flexible ureteroscope and holmium:YAG laser lithotripsy technique. If safe access cannot be obtained in the direct-RIRS group, rescue ureteral stenting will be performed, and definitive RIRS will be delayed for approximately 7-14 days.
The primary outcome will be the stone-free rate assessed by non-contrast computed tomography 4 weeks after the final RIRS procedure. Secondary outcomes will include successful ureteroscopic access, need for active dilation, procedure abandonment, staged RIRS, operative time, laser parameters, ureteral injury, postoperative complications, hospital stay, pain, stent-related symptoms, readmission, and auxiliary procedures.
- Conditions
- Renal Calculi
- Being tested
- Preoperative double-J ureteral stenting followed by retrograde intrarenal surgery, Direct retrograde intrarenal surgery without planned preoperative ureteral stenting
- Medical subject headings
- Kidney Calculi
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Preoperative double-J ureteral stenting followed by retrograde intrarenal surgeryProcedure or surgery
Participants randomized to this group will undergo insertion of a 4.8-6 French double-J ureteral stent approximately 7-14 days before definitive RIRS. The stent will be used to provide passive ureteral dilation. Definitive RIRS will then be performed using a miniaturized digital flexible ureteroscope and holmium:YAG laser lithotripsy.
The stent size, length, date of insertion, dwell time, technical success, complications, urinary tract infection, and stent-related symptoms will be recorded.
Direct retrograde intrarenal surgery without planned preoperative ureteral stentingProcedure or surgery
Participants randomized to this group will undergo direct RIRS without planned preoperative ureteral stenting. No routine active ureteral dilation will be performed before initial access. Gentle dilation may be performed when clinically necessary and will be documented.
If safe access cannot be achieved, the procedure will be discontinued and a double-J ureteral stent will be inserted for passive dilation. Repeat RIRS will be scheduled approximately 7-14 days later.
| Study group | Role | What they receive |
|---|---|---|
| Pre-stenting group | Experimental | Not described Receives: Procedure: Preoperative double-J ureteral stenting followed by retrograde intrarenal surgery |
| No-pre-stenting group | Active comparator | Not described Receives: Procedure: Direct retrograde intrarenal surgery without planned preoperative ureteral stenting |
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 using postoperative non-contrast computed tomography. The primary analysis will define stone-free status as absence of any residual renal stone fragment greater than 2 mm.
Measured: Four weeks after the final RIRS procedure
Secondary outcomes (4)
Successful renal access
Successful access is defined as passage of the flexible ureteroscope into the renal collecting system without unsafe resistance, significant ureteral injury, or procedure abandonment.
Measured: During the initial RIRS procedure
Need for active ureteral dilation
Proportion of participants requiring active ureteral dilation to facilitate safe ureteroscope or access-sheath passage.
Measured: During the initial RIRS procedure
Intraoperative ureteral injury
Ureteral injury, including mucosal abrasion, submucosal injury, perforation, false passage, significant edema, or ureteral avulsion, documented according to a predefined injury classification.
Measured: During each RIRS procedure
Postoperative complications
Postoperative complications will include fever, urinary tract infection, sepsis, hematuria, renal colic, urinary retention, ureteral obstruction, stent migration, stent encrustation, ureteral stricture, emergency-department visits, readmission, and the need for emergency or auxiliary treatment. Complications will be graded using the Clavien-Dindo classification.
Measured: From the initial RIRS procedure through 30 days after the final RIRS procedure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Aug 2026
- Study start19 Aug 2026
- Primary completion14 Aug 2028 (estimated)
- Study completion1 Nov 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Renal CalculiStudies of the same condition, open and under way.
- More trials run by Al-Azhar UniversityThe sponsor's other registered studies.
- 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
- Two-arm, parallel-group randomized controlled trial
- Masking
- None (open label)
- Enrolment
- 270 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Al-Azhar University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Abul-fotouh Ahmed, Al-Azhar University
- Investigators
- Abul-fotouh Ahmed, MD, Principal investigator, Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07773090
- Sponsor's protocol ID
- UroAzhar_17_026
- Status last verified
- Aug 2026
- First submitted
- 16 Aug 2026
- Last updated
- 21 Aug 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because the study involves clinical data collected from a single institutional population, and the informed-consent and ethical-approval framework does not include public release of participant-level data. De-identified aggregate results may be shared in publications or presentations.
Study at a glance
From the registry record, last updated by the sponsor on 21 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Does Pre-stenting Still Have a Role in Retrograde Intrarenal Surgery in the Era of Miniaturized Flexible Ureteroscopes? Surgical Outcomes From a Prospective Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07773090
- Acronym / sponsor ID
- UroAzhar_17_026
- Conditions
- Renal Calculi
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 270 participants (estimated)
- Lead sponsor
- Al-Azhar UniversityUniversity, hospital or other
- Study start
- 19 Aug 2026 (actual)
- Primary completion
- 14 Aug 2028 (estimated)
- Study completion
- 1 Nov 2028 (estimated)
- First posted
- 19 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This prospective randomized controlled trial will compare retrograde intrarenal surgery performed after routine preoperative ureteral stenting with direct retrograde intrarenal surgery without planned preoperative stenting in adults with unilateral renal calculi measuring 10-20 mm. The study will evaluate stone-free rate, ureteral access, need for rescue stenting, operative outcomes, complications, staged procedures, postoperative recovery, and auxiliary treatment.
Detailed description
Retrograde intrarenal surgery is widely used for the treatment of selected renal calculi. Miniaturized flexible ureteroscopes may facilitate direct ureteral and renal access, potentially reducing the need for routine preoperative ureteral stenting. However, pre-stenting may improve passive ureteral dilation, facilitate access, reduce failed access, and decrease the need for staged treatment.
Participants will be randomly assigned in a 1:1 ratio to either preoperative double-J ureteral stenting for 7-14 days followed by RIRS or direct RIRS without planned preoperative ureteral stenting. All procedures will use a standardized miniaturized digital flexible ureteroscope and holmium:YAG laser lithotripsy technique. If safe access cannot be obtained in the direct-RIRS group, rescue ureteral stenting will be performed, and definitive RIRS will be delayed for approximately 7-14 days.
The primary outcome will be the stone-free rate assessed by non-contrast computed tomography 4 weeks after the final RIRS procedure. Secondary outcomes will include successful ureteroscopic access, need for active dilation, procedure abandonment, staged RIRS, operative time, laser parameters, ureteral injury, postoperative complications, hospital stay, pain, stent-related symptoms, readmission, and auxiliary procedures.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Two-arm, parallel-group randomized controlled trial
| Arm | Type | Receives |
|---|---|---|
| Pre-stenting group | Experimental | Procedure: Preoperative double-J ureteral stenting followed by retrograde intrarenal surgery |
| No-pre-stenting group | Active comparator | Procedure: Direct retrograde intrarenal surgery without planned preoperative ureteral stenting |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- Participants must meet all of the following criteria:
Key exclusion criteria (16 listed)
- Participants will be excluded for any of the following:
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Preoperative double-J ureteral stenting followed by retrograde intrarenal surgeryParticipants randomized to this group will undergo insertion of a 4.8-6 French double-J ureteral stent approximately 7-14 days before definitive RIRS. The stent will be used to provide passive ureteral dilation. Definitive RIRS will then be performed using a miniaturized digital flexible ureteroscope and holmium:YAG laser lithotripsy. The stent size, length, date of insertion, dwell time, technical success, complications, urinary tract infection, and stent-related symptoms will be recorded. | Procedure or surgery | Pre-stenting group |
| Direct retrograde intrarenal surgery without planned preoperative ureteral stentingParticipants randomized to this group will undergo direct RIRS without planned preoperative ureteral stenting. No routine active ureteral dilation will be performed before initial access. Gentle dilation may be performed when clinically necessary and will be documented. If safe access cannot be achieved, the procedure will be discontinued and a double-J ureteral stent will be inserted for passive dilation. Repeat RIRS will be scheduled approximately 7-14 days later. | Procedure or surgery | No-pre-stenting group |
Primary outcome
Stone-free rate
Time frame: Four weeks after the final RIRS procedure
Stone-free status will be assessed using postoperative non-contrast computed tomography. The primary analysis will define stone-free status as absence of any residual renal stone fragment greater than 2 mm.
4 secondary outcomes
Successful renal access
Time frame: During the initial RIRS procedure
Need for active ureteral dilation
Time frame: During the initial RIRS procedure
Intraoperative ureteral injury
Time frame: During each RIRS procedure
Postoperative complications
Time frame: From the initial RIRS procedure through 30 days after the final RIRS procedure
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Aug 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared because the study involves clinical data collected from a single institutional population, and the informed-consent and ethical-approval framework does not include public release of participant-level data. De-identified aggregate results may be shared in publications or presentations.
Related trials for Renal Calculi
Not yet recruiting
Automated Versus Manual Irrigation During Flexible Ureteroscopy
Renal Stone Disease
Not yet recruiting
Optimal Intrarenal Pressure During Flexible Ureteroscopy
Renal Stone Disease
RecruitingObservational study
Stone Clearance With Aspiration vs Other Technologies: a Real-world Evidence Study
Urolithiasis, Stones, Kidney
Not yet recruiting
Intertransverse Process Block Versus Erector Spinae Plane Block for Postoperative Analgesia After Percutaneous Nephrolithotomy
Kidney Stones, Urolithiasis, Hypocitraturia, Pain, Postoperative
Not yet recruiting
Comparison of Smart Pressure-Controlled Flexible Ureteroscopy and Flexible Suction Ureteral Access Sheath-Assisted Flexible Ureteroscopy for 2-3 cm Renal Stones
Kidney Stones
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Abul-fotouh Ahmed, MD principal investigator
Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Preoperative double-J ureteral stenting followed by retrograde intrarenal surgery and Direct retrograde intrarenal surgery without planned preoperative ureteral stenting in people with Renal Calculi, run by Al-Azhar University at 1 site in Egypt.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 21 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Abul-fotouh Ahmed, MD (00201001066756, abulfotouhahmed@yahoo.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Stone-free rate (time frame: Four weeks after the final RIRS procedure). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Aug 2026.