UrolithiasisPFFINCT07763613
Clinical Evaluation of the Pelvic Floor Fatigue Index (PFFI)
An observational study of Urolithiasis, run by Trabzon Kanuni Education and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
Background: Ureteral stent-related symptoms vary considerably among patients despite similar surgical procedures and stent characteristics. Although several mechanisms have been proposed, the reasons for this interindividual variability remain incompletely understood. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Urolithiasis
- What is being tested?
- Ureteroscopy / Retrograde Intrarenal Surgery
- Type of treatment
- Surgery or procedure
- How many people
- 75 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 13 Aug 2026to 25 Dec 2026
- Phase
- Observational
- 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 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Adult patients with urolithiasis scheduled to undergo ureteroscopy (URS) or retrograde intrarenal surgery (RIRS) with postoperative double-J ureteral stent placement at the study center. Eligible participants will undergo standardized transabdominal ultrasonographic assessment of pelvic floor fatigability before surgery and will complete postoperative ureteral stent symptom assessment according to the study protocol.
Who may be able to join
- Adults aged 18-65 years. Diagnosis of urolithiasis requiring ureteroscopy (URS) or retrograde intrarenal surgery (RIRS).
- Planned postoperative double-J ureteral stent placement. Patients belonging to either the Non-pre-stented Group or the Pre-stented Group according to the study protocol.
- Ability to read and understand the validated Turkish version of the Ureteral Stent Symptom Questionnaire (USSQ).
- Ability to independently complete the USSQ. Ability to perform an adequate voluntary pelvic floor muscle contraction. Provision of written informed consent.
Who cannot join
- Clinically significant diabetic neuropathy. Neurological disorders affecting lower urinary tract function (e.g., multiple sclerosis, Parkinson's disease, spinal cord injury).
- Active lower urinary tract dysfunction (e.g., overactive bladder, neurogenic bladder, interstitial cystitis).
- Previous pelvic floor surgery. Known urinary incontinence. Urethral stricture. Chronic prostatitis. Recurrent urinary tract infection. Urinary tract malignancy. Advanced chronic kidney disease. Previous upper urinary tract reconstructive surgery. Pregnancy. Active urinary tract infection. Inability to perform an adequate voluntary pelvic floor muscle contraction. Inability 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.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Trabzon Kanuni Education and Research Hospital
Trabzon, Trabzon, 61080
adem deniz, md, +904623330030, adeemdeniz@gmail.com
recep erin, +904623330030, erinrecep@gmail.com
About this study
Official title: Development and Clinical Evaluation of the Pelvic Floor Fatigue Index (PFFI): A Prospective Observational Study
Background:
Ureteral stent-related symptoms vary considerably among patients despite similar surgical procedures and stent characteristics. Although several mechanisms have been proposed, the reasons for this interindividual variability remain incompletely understood. Pelvic floor muscle endurance may represent one of the patient-related factors contributing to symptom severity.
Read more
The Pelvic Floor Fatigue Index (PFFI) is a novel ultrasound-based index developed to quantify pelvic floor muscle endurance by measuring the percentage decline in bladder base elevation during a sustained maximum voluntary pelvic floor contraction using suprapubic transverse B-mode ultrasonography.
This prospective observational study aims to clinically evaluate the PFFI by investigating the association between preoperative PFFI measurements and postoperative ureteral stent-related symptoms assessed using the Ureteral Stent Symptom Questionnaire (USSQ). In addition, the study will evaluate the test-retest reliability of the PFFI measurement method and explore its potential role as an objective functional assessment tool for pelvic floor muscle endurance.
The findings of this study are expected to provide the first clinical evaluation of the PFFI and establish the methodological basis for future validation studies and broader clinical applications.
Read the detailed description
Background
Ureteral stent-related symptoms are common following ureteroscopy (URS) and retrograde intrarenal surgery (RIRS). Despite similar surgical procedures, stent characteristics, and postoperative management, symptom severity varies considerably among patients. Although trigonal irritation, local inflammation, vesicoureteral reflux, and the mechanical effects of the distal stent have been proposed as contributing mechanisms, these factors do not fully explain the observed interindividual variability.
Pelvic floor muscle function may represent an additional patient-related factor influencing symptom severity. While current assessment methods primarily evaluate maximal voluntary contraction or anatomical movement, no standardized ultrasound-based method is currently available to objectively quantify pelvic floor muscle endurance.
Study Rationale
The Pelvic Floor Fatigue Index (PFFI) was developed to provide an objective, non-invasive, and reproducible ultrasound-based assessment of pelvic floor muscle endurance. The index quantifies the percentage decline in bladder base elevation during a sustained maximum voluntary pelvic floor contraction using suprapubic transverse B-mode ultrasonography.
Unlike conventional pelvic floor assessments that primarily measure maximal contraction, PFFI evaluates the ability to maintain that contraction over time, providing complementary information regarding pelvic floor functional performance.
Study Objectives
The primary objective of this study is to clinically evaluate the Pelvic Floor Fatigue Index (PFFI) by investigating the association between preoperative PFFI measurements and postoperative ureteral stent-related symptoms assessed using the Ureteral Stent Symptom Questionnaire (USSQ).
Secondary objectives include evaluating the reliability of the PFFI measurement method using test-retest analysis and assessing the influence of selected clinical variables on PFFI measurements.
- Conditions
- Urolithiasis
- Being tested
- Ureteroscopy / Retrograde Intrarenal Surgery
- Keywords
- Pelvic Floor Fatigue Index, PFFI, Ureteral Stent, Ureteral Stent-Related Symptoms, Ureteral Stent Symptom Questionnaire, USSQ, Pelvic Floor Muscle Endurance, Urolithiasis, Ureteroscopy, Retrograde Intrarenal Surgery
- Medical subject headings
- Urolithiasis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Ureteroscopy / Retrograde Intrarenal SurgeryProcedure or surgery
Ureteroscopy or retrograde intrarenal surgery (RIRS) will be performed for the treatment of urolithiasis according to routine clinical practice. No additional procedural intervention will be assigned by the study protocol.
| Study group | Role | What they receive |
|---|---|---|
| Pre-stented Group | Patients undergoing ureteroscopy or retrograde intrarenal surgery (RIRS) who have a ureteral stent in place before the index procedure. Receives: Procedure: Ureteroscopy / Retrograde Intrarenal Surgery | |
| Non-pre-stented Group | Patients undergoing ureteroscopy or retrograde intrarenal surgery (RIRS) without a ureteral stent in place before the index procedure. Receives: Procedure: Ureteroscopy / Retrograde Intrarenal Surgery |
What is being measured
The primary outcome is the main question the study is designed to answer.
Association Between Preoperative PFFI and Postoperative Total USSQ Score
The association between the preoperative Pelvic Floor Fatigue Index (PFFI) and postoperative ureteral stent-related symptom burden will be assessed using the total Ureteral Stent Symptom Questionnaire (USSQ) score obtained on postoperative Day 10. Higher PFFI values indicate greater pelvic floor fatigability, and higher total USSQ scores indicate greater stent-related symptom burden.
Measured: Preoperative assessment to postoperative Day 10
Secondary outcomes (3)
Association Between Preoperative Dmax and Postoperative Total USSQ Score
The association between preoperative Dmax, defined as the maximum bladder base elevation measured during a maximum voluntary pelvic floor contraction using suprapubic transverse B-mode ultrasonography, and postoperative ureteral stent-related symptom burden will be assessed using the total Ureteral Stent Symptom Questionnaire (USSQ) score obtained on postoperative Day 10.
Measured: Preoperative assessment to postoperative Day 10
Test-Retest Reliability of PFFI Measurement
The intra-rater test-retest reliability of PFFI measurement will be evaluated in the first 12 participants. PFFI measurements will be repeated by the same investigator under standardized conditions following a rest period of approximately 10-15 minutes. Reliability will be assessed using the Intraclass Correlation Coefficient (ICC), and agreement between repeated measurements will additionally be evaluated using Bland-Altman analysis.
Measured: During the same preoperative assessment session, with approximately 10-15 minutes between measurements
Change in PFFI From Preoperative Assessment to Postoperative Day 10
Pelvic floor fatigability will be assessed using the Pelvic Floor Fatigue Index (PFFI) before surgery and again on postoperative Day 10 while the ureteral stent is in situ. The change in PFFI between the two assessments will be evaluated to determine whether ureteral stenting is associated with a change in pelvic floor fatigability.
Measured: Preoperative assessment and postoperative Day 10
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Aug 2026
- Study start13 Aug 2026
- Primary completion25 Dec 2026 (estimated)
- Study completion25 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for UrolithiasisStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 75 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Trabzon Kanuni Education and Research Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07763613
- Sponsor's protocol ID
- PFFI-2026-01
- Other IDs
- 10496660-2026/26214
- Acronym
- PFFI
- Status last verified
- Aug 2026
- First submitted
- 8 Aug 2026
- Last updated
- 18 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be publicly shared due to participant confidentiality and institutional data protection considerations.
Study at a glance
From the registry record, last updated by the sponsor on 18 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Development and Clinical Evaluation of the Pelvic Floor Fatigue Index (PFFI): A Prospective Observational Study
- ClinicalTrials.gov ID
- NCT07763613
- Acronym / sponsor ID
- PFFI / PFFI-2026-01
- Conditions
- Urolithiasis
- Keywords
- Pelvic Floor Fatigue Index, PFFI, Ureteral Stent, Ureteral Stent-Related Symptoms, Ureteral Stent Symptom Questionnaire, USSQ, Pelvic Floor Muscle Endurance, Urolithiasis
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 75 participants (estimated)
- Lead sponsor
- Trabzon Kanuni Education and Research HospitalUniversity, hospital or other
- Study start
- 13 Aug 2026 (actual)
- Primary completion
- 25 Dec 2026 (estimated)
- Study completion
- 25 Dec 2026 (estimated)
- First posted
- 13 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.
Background:
Ureteral stent-related symptoms vary considerably among patients despite similar surgical procedures and stent characteristics. Although several mechanisms have been proposed, the reasons for this interindividual variability remain incompletely understood. Pelvic floor muscle endurance may represent one of the patient-related factors contributing to symptom severity.
The Pelvic Floor Fatigue Index (PFFI) is a novel ultrasound-based index developed to quantify pelvic floor muscle endurance by measuring the percentage decline in bladder base elevation during a sustained maximum voluntary pelvic floor contraction using suprapubic transverse B-mode ultrasonography.
This prospective observational study aims to clinically evaluate the PFFI by investigating the association between preoperative PFFI measurements and postoperative ureteral stent-related symptoms assessed using the Ureteral Stent Symptom Questionnaire (USSQ). In addition, the study will evaluate the test-retest reliability of the PFFI measurement method and explore its potential role as an objective functional assessment tool for pelvic floor muscle endurance.
The findings of this study are expected to provide the first clinical evaluation of the PFFI and establish the methodological basis for future validation studies and broader clinical applications.
Detailed description
Background
Ureteral stent-related symptoms are common following ureteroscopy (URS) and retrograde intrarenal surgery (RIRS). Despite similar surgical procedures, stent characteristics, and postoperative management, symptom severity varies considerably among patients. Although trigonal irritation, local inflammation, vesicoureteral reflux, and the mechanical effects of the distal stent have been proposed as contributing mechanisms, these factors do not fully explain the observed interindividual variability.
Pelvic floor muscle function may represent an additional patient-related factor influencing symptom severity. While current assessment methods primarily evaluate maximal voluntary contraction or anatomical movement, no standardized ultrasound-based method is currently available to objectively quantify pelvic floor muscle endurance.
Study Rationale
The Pelvic Floor Fatigue Index (PFFI) was developed to provide an objective, non-invasive, and reproducible ultrasound-based assessment of pelvic floor muscle endurance. The index quantifies the percentage decline in bladder base elevation during a sustained maximum voluntary pelvic floor contraction using suprapubic transverse B-mode ultrasonography.
Unlike conventional pelvic floor assessments that primarily measure maximal contraction, PFFI evaluates the ability to maintain that contraction over time, providing complementary information regarding pelvic floor functional performance.
Study Objectives
The primary objective of this study is to clinically evaluate the Pelvic Floor Fatigue Index (PFFI) by investigating the association between preoperative PFFI measurements and postoperative ureteral stent-related symptoms assessed using the Ureteral Stent Symptom Questionnaire (USSQ).
Secondary objectives include evaluating the reliability of the PFFI measurement method using test-retest analysis and assessing the influence of selected clinical variables on PFFI measurements.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Pre-stented Group | – | Procedure: Ureteroscopy / Retrograde Intrarenal SurgeryPatients undergoing ureteroscopy or retrograde intrarenal surgery (RIRS) who have a ureteral stent in place before the index procedure. |
| Non-pre-stented Group | – | Procedure: Ureteroscopy / Retrograde Intrarenal SurgeryPatients undergoing ureteroscopy or retrograde intrarenal surgery (RIRS) without a ureteral stent in place before the index procedure. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adult patients with urolithiasis scheduled to undergo ureteroscopy (URS) or retrograde intrarenal surgery (RIRS) with postoperative double-J ureteral stent placement at the study center. Eligible participants will undergo standardized transabdominal ultrasonographic assessment of pelvic floor fatigability before surgery and will complete postoperative ureteral stent symptom assessment according to the study protocol.
Key inclusion criteria (4 listed)
- Adults aged 18-65 years. Diagnosis of urolithiasis requiring ureteroscopy (URS) or retrograde intrarenal surgery (RIRS).
- Planned postoperative double-J ureteral stent placement. Patients belonging to either the Non-pre-stented Group or the Pre-stented Group according to the study protocol.
- Ability to read and understand the validated Turkish version of the Ureteral Stent Symptom Questionnaire (USSQ).
- Ability to independently complete the USSQ. Ability to perform an adequate voluntary pelvic floor muscle contraction. Provision of written informed consent.
Key exclusion criteria (3 listed)
- Clinically significant diabetic neuropathy. Neurological disorders affecting lower urinary tract function (e.g., multiple sclerosis, Parkinson's disease, spinal cord injury).
- Active lower urinary tract dysfunction (e.g., overactive bladder, neurogenic bladder, interstitial cystitis).
- Previous pelvic floor surgery. Known urinary incontinence. Urethral stricture. Chronic prostatitis. Recurrent urinary tract infection. Urinary tract malignancy. Advanced chronic kidney disease. Previous upper urinary tract reconstructive surgery. Pregnancy. Active urinary tract infection. Inability to perform an adequate voluntary pelvic floor muscle contraction. Inability to provide informed consent.
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 |
|---|---|---|
| Ureteroscopy / Retrograde Intrarenal SurgeryUreteroscopy or retrograde intrarenal surgery (RIRS) will be performed for the treatment of urolithiasis according to routine clinical practice. No additional procedural intervention will be assigned by the study protocol. | Procedure or surgery | Non-pre-stented Group, Pre-stented Group |
Primary outcome
Association Between Preoperative PFFI and Postoperative Total USSQ Score
Time frame: Preoperative assessment to postoperative Day 10
The association between the preoperative Pelvic Floor Fatigue Index (PFFI) and postoperative ureteral stent-related symptom burden will be assessed using the total Ureteral Stent Symptom Questionnaire (USSQ) score obtained on postoperative Day 10. Higher PFFI values indicate greater pelvic floor fatigability, and higher total USSQ scores indicate greater stent-related symptom burden.
3 secondary outcomes
Association Between Preoperative Dmax and Postoperative Total USSQ Score
Time frame: Preoperative assessment to postoperative Day 10
Test-Retest Reliability of PFFI Measurement
Time frame: During the same preoperative assessment session, with approximately 10-15 minutes between measurements
Change in PFFI From Preoperative Assessment to Postoperative Day 10
Time frame: Preoperative assessment and postoperative Day 10
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 18 Aug 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be publicly shared due to participant confidentiality and institutional data protection considerations.
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Urolithiasis, run by Trabzon Kanuni Education and Research Hospital 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 3 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 18 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 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 ADEM DENİZ, MD (+904623330030, adeemdeniz@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Association Between Preoperative PFFI and Postoperative Total USSQ Score (time frame: Preoperative assessment to postoperative Day 10). 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 18 Aug 2026.