Stone, KidneyPOS-RIRS-RCTNCT06809582
Impact of Surgical Position on Stone-Free Rates in Retrograde Intrarenal Surgery
A study testing The T-Tilt position in people with Stone, Kidney and Stones, Kidney, run by Ondokuz Mayıs University at 1 site in Turkey (Türkiye).
Trial summary
The goal of this clinical trial is to determine whether the surgical position during retrograde intrarenal surgery (RIRS) affects stone-free rates in adults with kidney stones. The main questions it aims to answer are: Does the modified lithotomy position result in a higher stone-free rate compared to the standard… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Stone, Kidney, Stones, Kidney, Stone;Renal
- What is being tested?
- The T-Tilt position
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 128 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Jan 2025to 1 Jun 2026
- 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Presence of single or multiple kidney stones, with the largest stone ≤2 cm
- Age ≥18 years
- Provided written informed consent to participate in the study
- Indicated for retrograde intrarenal surgery (RIRS) as a treatment approach
Who cannot join
- Severe cardiovascular disease (e.g., heart failure)
- Congenital kidney anomalies (e.g., horseshoe kidney, ectopic kidney)
- Concurrent ureteral stones
- Pregnancy or planning pregnancy
- History of previous kidney surgery on the same side
- Active urinary tract infection (UTI)
- Coagulopathy or use of anticoagulant therapy that cannot be stopped before surgery
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Ondokuz Mayıs University
Samsun
Murat Gulsen, +905062357421, mglotr@gmail.com
About this study
Official title: Does the Positioning in Retrograde Intrarenal Surgery Affect Stone-Free Rates? A Prospective Randomized Controlled Trial
The goal of this clinical trial is to determine whether the surgical position during retrograde intrarenal surgery (RIRS) affects stone-free rates in adults with kidney stones. The main questions it aims to answer are:
- Does the modified lithotomy position result in a higher stone-free rate compared to the standard lithotomy position?
- Are there differences in complication rates between the two surgical positions?
Read more
Researchers will compare patients undergoing RIRS in the standard lithotomy position to those in the modified lithotomy position (30-degree Trendelenburg with elevated surgical side) to assess its impact on stone clearance and surgical outcomes.
Participants will:
- Be randomly assigned to one of two surgical positions
- Undergo RIRS with standard surgical procedures
- Have follow-up imaging to assess stone clearance after surgery
This study aims to improve surgical techniques and patient outcomes in kidney stone treatment.
- Conditions
- Stone, Kidney, Stones, Kidney, Stone;Renal
- Being tested
- The T-Tilt position
- 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.
The T-Tilt positionProcedure or surgery
The T-Tilt position is a modified lithotomy position used during retrograde intrarenal surgery (RIRS). In this position:
The patient is placed in a 30-degree Trendelenburg position, meaning the head is slightly lower than the feet.
The surgical side is elevated at a 30-degree angle to improve access to the kidney.
This modified positioning is designed to enhance stone clearance, particularly by facilitating the movement of stone fragments away from the lower kidney calyces, where residual stones often remain. Researchers will compare this position to the standard lithotomy position to determine its impact on stone-free rates and surgical outcomes.
| Study group | Role | What they receive |
|---|---|---|
| Standard lithotomy position | No intervention | In this arm we will use standard lithotomy position as control group. |
| T-Tilt Lithotomy Position | Active comparator | Not described Receives: Procedure: The T-Tilt position |
What is being measured
The primary outcome is the main question the study is designed to answer.
Stone-Free Rate After Retrograde Intrarenal Surgery
The percentage of participants with no residual kidney stones (≤4 mm fragments) on non-contrast computed tomography (CT) at 6 weeks postoperatively.
Measured: 6 weeks post-surgery
Secondary outcomes (1)
Postoperative Complication Rate
he percentage of participants experiencing any postoperative complications, classified according to the Clavien-Dindo grading system.
Measured: Within 30 days post-surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Feb 2025
- Study start1 Jan 2025
- Primary completion1 Dec 2025 (estimated)
- Study completion1 Jun 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Stone, KidneyStudies of the same condition, open and under way.
- More trials run by Ondokuz Mayıs 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
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 128 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ondokuz Mayıs University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Murat Gulsen, Ondokuz Mayıs University
- Investigators
- Murat Gulsen, Principal investigator, Ondokuz Mayıs University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06809582
- Sponsor's protocol ID
- B.30.2.ODM.0.20.08/603-670
- Acronym
- POS-RIRS-RCT
- Status last verified
- Aug 2025
- First submitted
- 30 Jan 2025
- Last updated
- 15 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Canakci C, Dincer E, Can U, Coskun A, Otbasan BK, Ozkaptan O. The relationship between stone-free and patient position in retrograde intrarenal surgery: a randomized prospective study. World J Urol. 2024 May 9;42(1):308. doi: 10.1007/s00345-024-05013-1.
PubMed 38722376Liaw CW, Khusid JA, Gallante B, Bamberger JN, Atallah WM, Gupta M. The T-Tilt Position: A Novel Modified Patient Position to Improve Stone-Free Rates in Retrograde Intrarenal Surgery. J Urol. 2021 Nov;206(5):1232-1239. doi: 10.1097/JU.0000000000001948. Epub 2021 Jul 12.
PubMed 34251886
Study at a glance
From the registry record, last updated by the sponsor on 15 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Does the Positioning in Retrograde Intrarenal Surgery Affect Stone-Free Rates? A Prospective Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT06809582
- Acronym / sponsor ID
- POS-RIRS-RCT / B.30.2.ODM.0.20.08/603-670
- Conditions
- Stone, Kidney, Stones, Kidney, Stone;Renal
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 128 participants (estimated)
- Lead sponsor
- Ondokuz Mayıs UniversityUniversity, hospital or other
- Study start
- 1 Jan 2025 (actual)
- Primary completion
- 1 Dec 2025 (estimated)
- Study completion
- 1 Jun 2026 (estimated)
- First posted
- 5 Feb 2025 (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.
The goal of this clinical trial is to determine whether the surgical position during retrograde intrarenal surgery (RIRS) affects stone-free rates in adults with kidney stones. The main questions it aims to answer are:
- Does the modified lithotomy position result in a higher stone-free rate compared to the standard lithotomy position?
- Are there differences in complication rates between the two surgical positions?
Researchers will compare patients undergoing RIRS in the standard lithotomy position to those in the modified lithotomy position (30-degree Trendelenburg with elevated surgical side) to assess its impact on stone clearance and surgical outcomes.
Participants will:
- Be randomly assigned to one of two surgical positions
- Undergo RIRS with standard surgical procedures
- Have follow-up imaging to assess stone clearance after surgery
This study aims to improve surgical techniques and patient outcomes in kidney stone treatment.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Standard lithotomy position | No intervention | –In this arm we will use standard lithotomy position as control group. |
| T-Tilt Lithotomy Position | Active comparator | Procedure: The T-Tilt position |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Presence of single or multiple kidney stones, with the largest stone ≤2 cm
- Age ≥18 years
- Provided written informed consent to participate in the study
- Indicated for retrograde intrarenal surgery (RIRS) as a treatment approach
Key exclusion criteria (7 listed)
- Severe cardiovascular disease (e.g., heart failure)
- Congenital kidney anomalies (e.g., horseshoe kidney, ectopic kidney)
- Concurrent ureteral stones
- Pregnancy or planning pregnancy
- History of previous kidney surgery on the same side
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 |
|---|---|---|
| The T-Tilt positionThe T-Tilt position is a modified lithotomy position used during retrograde intrarenal surgery (RIRS). In this position: The patient is placed in a 30-degree Trendelenburg position, meaning the head is slightly lower than the feet. The surgical side is elevated at a 30-degree angle to improve access to the kidney. This modified positioning is designed to enhance stone clearance, particularly by facilitating the movement of stone fragments away from the lower kidney calyces, where residual stones often remain. Researchers will compare this position to the standard lithotomy position to determine its impact on stone-free rates and surgical outcomes. | Procedure or surgery | T-Tilt Lithotomy Position |
Primary outcome
Stone-Free Rate After Retrograde Intrarenal Surgery
Time frame: 6 weeks post-surgery
The percentage of participants with no residual kidney stones (≤4 mm fragments) on non-contrast computed tomography (CT) at 6 weeks postoperatively.
1 secondary outcome
Postoperative Complication Rate
Time frame: Within 30 days post-surgery
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 15 Aug 2025.
- Results publication: PubMed 38722376Canakci C, Dincer E, Can U, Coskun A, Otbasan BK, Ozkaptan O. The relationship between stone-free and patient position in retrograde intrarenal surgery: a randomized prospective study. World J Urol. 2024 May 9;42(1):308. doi: 10.1007/s00345-024-05013-1.
- Results publication: PubMed 34251886Liaw CW, Khusid JA, Gallante B, Bamberger JN, Atallah WM, Gupta M. The T-Tilt Position: A Novel Modified Patient Position to Improve Stone-Free Rates in Retrograde Intrarenal Surgery. J Urol. 2021 Nov;206(5):1232-1239. doi: 10.1097/JU.0000000000001948. Epub 2021 Jul 12.
- Individual participant dataSharing planned: No
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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.
Murat Gulsen principal investigator
Ondokuz Mayıs University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing The T-Tilt position in people with Stone, Kidney and Stones, Kidney, run by Ondokuz Mayıs University at 1 site in Turkey (Türkiye).
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 4 inclusion and 7 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 15 Aug 2025. 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 Turkey (Türkiye). 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 Murat Gulsen (+905062357421, mglotr@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Stone-Free Rate After Retrograde Intrarenal Surgery (time frame: 6 weeks post-surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06809582, which also lists 2 linked publications.
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 15 Aug 2025; AzTrials last refreshed its copy on 8 Nov 2026.