An observational study in Urethral Stricture, sponsored by Ankara City Hospital Bilkent. Recruiting at 1 site in Turkey (Türkiye). Open to male participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-03.
Sponsored by Ankara City Hospital Bilkent · Observational
This prospective observational study aims to evaluate the diagnostic accuracy of a new, non-invasive uroflowmetry parameter called the Urethral Resistive Index (URI) for detecting urethral stricture in men. Currently, diagnosing urethral stricture often requires invasive procedures like surgery or pressure-flow studies. This research seeks to develop URI as a practical and painless screening tool that could reduce the need for such invasive interventions.
Study Procedures:
A total of 60 male participants (30 with suspected urethral stricture and 30 healthy volunteers) will be enrolled. Participants will undergo two standard, non-invasive uroflowmetry (voiding) tests. The first test is a routine natural voiding session. The second test involves a "forced voiding" (Valsalva maneuver) once the participant feels a sufficient urge to urinate again. The URI is then calculated by comparing the flow rates of these two sessions.
Goals and Benefits: The primary goal is to determine the optimal "cut-off" value of the URI that accurately identifies a surgically proven urethral stricture. By demonstrating URI's effectiveness, the study aims to expedite the diagnostic process and spare patients from unnecessary invasive tests. The procedure involves minimal risk, primarily temporary discomfort or psychological stress during the voiding tests
This methodological study is designed as a prospective, cross-sectional, and observational diagnostic accuracy study. The primary objective is to evaluate the clinical validity of the Urethral Resistive Index (URI), a novel non-invasive parameter, in the diagnosis of urethral stricture.
Study Population and Groups:
The study will include a total of 60 male participants aged between 18 and 80 years.
Stricture Group (n=30): Patients planned for surgery (urethroplasty or internal urethrotomy) due to suspected urethral stricture, where the presence of the stricture is confirmed intraoperatively.
Control Group (n=30): Healthy male volunteers without lower urinary tract symptoms, matched for age.
Methodology: The study focuses on comparing standard uroflowmetry with "forced" uroflowmetry using the Valsalva maneuver. All clinical and uroflowmetric parameters will be collected at the Ankara Bilkent City Hospital Urology Clinic.
Natural Uroflowmetry: Participants will perform a standard uroflowmetry test. Forced Uroflowmetry: After reaching sufficient bladder fullness again, participants will perform a second test using the Valsalva maneuver (forced voiding).
Calculation: The URI will be calculated using the formula:
URI= Qmax,forced/ Qmax,normal
Statistical Analysis: The diagnostic performance of the URI will be evaluated using Receiver Operating Characteristic (ROC) curve analysis. The Area Under the Curve (AUC) will be calculated, and the optimal cut-off value for determining urethral stricture will be identified with corresponding sensitivity and specificity values. Correlation between URI and clinical symptom scores, such as the International Prostate Symptom Score (IPSS), will also be analyzed.
72 studies on the registry are indexed under Urethral Stricture; 25 are open to participants now.
This study's planned enrollment of 60 is below the median of 175 across 11 observational studies indexed under Urethral Stricture.
Browse Urethral Stricture studies →Ankara City Hospital Bilkent is the lead sponsor of 443 studies on the registry; 111 are open to participants now.
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The study population consists of 60 male participants, aged 18 to 80 years, recruited from the Urology Outpatient Clinic at Ankara Bilkent City Hospital. The population is divided into two distinct groups: a Stricture Group (n=30) comprising patients with suspected urethral stricture whose diagnosis is confirmed intraoperatively during scheduled surgery, and a Control Group (n=30) comprising healthy male volunteers with a similar age distribution and no lower urinary tract symptoms. Participants are selected based on their clinical presentation and willingness to undergo a specialized two-stage uroflowmetry protocol.
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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.
Patients with suspected urethral stricture scheduled for surgery (urethroplasty or internal urethrotomy), with the diagnosis confirmed intraoperatively.
Diagnostic Test: Uroflowmetry with URI Calculation
Healthy male volunteers in a similar age range as the stricture group, without any lower urinary tract symptoms.
Diagnostic Test: Uroflowmetry with URI Calculation
Performing natural and forced (Valsalva) uroflowmetry sessions to calculate the Urethral Resistive Index.
Urethral Resistive Index (URI)
A novel non-invasive uroflowmetric parameter calculated to assess the resistance of the urethra during voiding. It is derived using the formula: URI=Qmax,natural/Qmax,forced.
Time frame: At the time of the uroflowmetry procedure (Baseline)
Plan to share: No — To protect participant privacy and maintain data confidentiality according to local institutional regulations
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 ↗
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