Urethral Resistive Index (URI): A New Parameter for Diagnosing Urethral Obstruction

NCT07403786 | Not Yet Recruiting

• 1 other identifier: TABED 1/2090/2026
• Study Type: observational
• Target: 60
• Locations: 0 countries
• Sites: N/A

Brief Summary

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

Conditions

Urethral Stricture

Outcome Measures

Primary Outcomes (1)

• 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.

  At the time of the uroflowmetry procedure (Baseline)

Study Arms (2)

Stricture Group

Patients with suspected urethral stricture scheduled for surgery (urethroplasty or internal urethrotomy), with the diagnosis confirmed intraoperatively.

Diagnostic Test: Uroflowmetry with URI Calculation

Control Group

Healthy male volunteers in a similar age range as the stricture group, without any lower urinary tract symptoms.

Diagnostic Test: Uroflowmetry with URI Calculation

Interventions

Uroflowmetry with URI Calculation DIAGNOSTIC_TEST

Performing natural and forced (Valsalva) uroflowmetry sessions to calculate the Urethral Resistive Index.

Control Group; Stricture Group

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

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.

You may qualify if:

• Male participants aged between 18 and 80 years.
• For the Stricture Group: Patients scheduled for surgery (urethroplasty or internal urethrotomy) due to suspected urethral stricture, where the diagnosis is confirmed intraoperatively.
• For the Control Group: Healthy male volunteers without any lower urinary tract symptoms.
• Voluntary signing of the Informed Consent Form.

You may not qualify if:

• Voiding volume less than 150 mL.
• Causes of obstruction other than stricture, such as Benign Prostatic Hyperplasia (BPH).
• Diagnosis of neurogenic bladder dysfunction or a history of neurological disease affecting bladder function.
• Presence of severe comorbidities.

Sponsors & Collaborators

• Ankara City Hospital Bilkent: lead

Related Publications (3)

• Kranse R, van Mastrigt R. Bladder outlet resistance. J Urol. 2003 Mar;169(3):1007-10. doi: 10.1097/01.ju.0000052693.58772.23.

  PMID: 12576832 BACKGROUND

• Spyropoulos E, Galanakis I, Deligiannis D, Spyropoulou A, Kotsiris D, Panagopoulos A, Mavrikos S. Flow resistive forces index (QRF): Development and clinical applicability assessment of a novel measure of bladder outlet resistance, aiming to enhance the diagnostic performance of uroflowmetry. Low Urin Tract Symptoms. 2020 Sep;12(3):190-197. doi: 10.1111/luts.12301. Epub 2020 Jan 30.

  PMID: 31999073 BACKGROUND

• Krukowski J, Kaluzny A, Klacz J, Piatkowska A, Matuszewski M. Evaluation of non-invasive tests as diagnostic tools in assessment of bladder outlet obstruction severity in men with anterior urethral stricture. Cent European J Urol. 2021;74(3):422-428. doi: 10.5173/ceju.2021.3.153.R1. Epub 2021 Jul 27.

  PMID: 34729232 BACKGROUND

MeSH Terms

Conditions

Urethral Stricture

Condition Hierarchy (Ancestors)

Urethral Obstruction; Urethral Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases

Central Study Contacts

Yusuf Gökkurt

CONTACT

+90-506-791-0557; yusufgokkurt@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Attending Physician, Department of Urology

Study Record Dates

• First Submitted: February 5, 2026
• First Posted: February 11, 2026
• Study Start: February 9, 2026
• Primary Completion: May 10, 2026
• Study Completion (Estimated): July 10, 2026
• Last Updated: February 11, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share