From the Guidelines
Urodynamics testing in a urogynecology clinic is a crucial diagnostic tool that helps evaluate the function of the bladder, sphincters, and urethra, and it should be performed at the clinician's discretion in certain patients, including those with a history of prior anti-incontinence surgery, prior POP surgery, or significant voiding dysfunction, as recommended by the AUA/SUFU guideline 1. The test typically involves several components:
- Uroflowmetry (measuring urine flow rate)
- Filling cystometry (assessing bladder function during filling)
- Pressure-flow studies (evaluating voiding)
- Sometimes electromyography (measuring pelvic floor muscle activity) During the procedure, a thin catheter is inserted into the bladder to fill it with sterile water or saline while measuring pressures in the bladder and abdomen. Patients are asked to report sensations like first desire to void and urgency, then to urinate with the catheters in place. Interpretation focuses on several key parameters:
- Bladder capacity (normally 300-500ml)
- Detrusor function (looking for overactivity or underactivity)
- Bladder compliance
- Urethral function
- Post-void residual volume Abnormal findings might include detrusor overactivity (involuntary bladder contractions), stress urinary incontinence (leakage with increased abdominal pressure), voiding dysfunction, or bladder outlet obstruction. The test helps differentiate between various types of incontinence and voiding disorders, guiding appropriate treatment selection, as outlined in the AUA/SUFU guideline for urodynamic studies in adults 1. Patients should expect the procedure to take 30-60 minutes and may experience mild discomfort, temporary urinary urgency, or slight bleeding afterward, and they should be advised to increase fluid intake following the test to reduce infection risk. It is essential to weigh the benefits of urodynamic testing against the risks, including infection, urethral trauma, and pain, and to consider the patient's individual circumstances, such as a history of prior surgery or significant voiding dysfunction, when deciding whether to perform the test, as recommended by the AUA/SUFU guideline 1.
From the Research
Urodynamics Testing for Women
Urodynamics testing is an exam intended to explore the mechanisms underlying lower urinary tract symptoms (LUTS) or urinary incontinence (UI) in women visiting a urogynecology clinic. The test involves:
- Measurement of bladder and sphincter pressures using uretrovesical and rectal catheters with pressure transducers
- Measurement of urinary flow and bladder sensation during filling 2
- The test is not systematic in the assessment of LUTS or UI and must seek to tackle a specific clinical or therapeutic question
Steps Involved in Urodynamics Testing
The steps involved in urodynamics testing include:
- Free (unintubated) uroflowmetry
- Cystometry
- Post-void residual measurement
- Urethral profilometry (optional)
- Pressure-flow study or sensitization tests 2
Interpretation of Urodynamics Testing
The interpretation of urodynamics testing is essential to confirm the diagnosis, counsel the patient, and choose treatment. The test is helpful in evaluating:
- Mixed urinary incontinence
- Voiding lower urinary tract symptoms 3
- The information obtained from urodynamics testing assists the clinician in making informed decisions about treatment
Importance of Urodynamics Testing
Urodynamics testing remains the test of choice to evaluate lower urinary tract symptoms in women, but it is not necessary for the evaluation of pure clinical stress urinary incontinence or before conservative treatment of overactive bladder 3. The competence of the nurse ensures the reliability, reproducibility, and interpretability of the urodynamics study, and their humanity guarantees a favorable atmosphere for this uncomfortable and invasive test 2