An observational study in Urolithiasis, sponsored by Trabzon Kanuni Education and Research Hospital. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-08-18.
Sponsored by Trabzon Kanuni Education and Research Hospital · Observational
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.
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.
253 studies on the registry are indexed under Urolithiasis; 67 are open to participants now.
This study's planned enrollment of 75 is below the median of 150 across 65 observational studies indexed under Urolithiasis.
Browse Urolithiasis studies →Trabzon Kanuni Education and Research Hospital is the lead sponsor of 12 studies on the registry; 4 are open to participants now.
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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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
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 .
Exclusion Criteria:
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 . 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 .
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.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
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.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients undergoing ureteroscopy or retrograde intrarenal surgery (RIRS) who have a ureteral stent in place before the index procedure.
Procedure: Ureteroscopy / Retrograde Intrarenal Surgery
Patients undergoing ureteroscopy or retrograde intrarenal surgery (RIRS) without a ureteral stent in place before the index procedure.
Procedure: Ureteroscopy / Retrograde Intrarenal 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.
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.
Time frame: Preoperative assessment to postoperative Day 10
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.
Time frame: 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.
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
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.
Time frame: Preoperative assessment and postoperative Day 10
Plan to share: No — Individual participant data will not be publicly shared due to participant confidentiality and institutional data protection considerations.
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Trabzon Kanuni Education and Research Hospital