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Ultrasonography of the Adult Male Urinary Tract for Urinary Functional Testing
Published on: August 14, 2019
The effect of urethral instrumentation on uroflowmetry
1Department of Urology, Emory University School of Medicine, and Atlanta Veterans Affairs Medical Center, Atlanta, Georgia 30322, USA. muta.issa@med.va.gov
BJU International
|August 22, 2003
Summary
Flexible cystoscopy significantly impacts peak urinary flow rate (Qmax) measurements. Uroflowmetry data collected after urethral instrumentation should be excluded to avoid falsely indicating treatment improvement.
Area of Science:
- Urology
- Medical Instrumentation
Background:
- Uroflowmetry is a key diagnostic tool for lower urinary tract symptoms.
- Flexible cystoscopy is commonly used for urethral and bladder evaluation.
- Accurate uroflowmetry is crucial for assessing treatment efficacy in conditions like benign prostatic obstruction.
Purpose of the Study:
- To prospectively assess the effect of flexible cystoscopy on uroflowmetry, specifically peak urinary flow rate (Qmax).
- To determine if urethral instrumentation influences subsequent Qmax measurements.
Main Methods:
- 32 patients undergoing flexible cystoscopy had uroflowmetry performed immediately before and after the procedure.
- Exclusion criteria included active urethral stricture or urinary infection.
- Post-void residual volume (PVR) was measured, and bladder volume was normalized with saline before post-procedure uroflowmetry.
Main Results:
- Mean Qmax decreased significantly after flexible cystoscopy (16.9 mL/s pre vs. 13.3 mL/s post, P=0.029).
- A mean percentage difference of +27% indicated higher Qmax before instrumentation.
- A notable proportion of patients (up to 25%) showed a reduction in Qmax post-procedure.
Conclusions:
- Urethral instrumentation via flexible cystoscopy significantly alters Qmax.
- Using post-instrumentation uroflowmetry can lead to a misleading "improvement" in Qmax by up to 27%.
- Excluding post-instrumentation uroflowmetry data is essential for accurate assessment of therapies for conditions like benign prostatic obstruction.
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