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Urodynamic studies provide comprehensive evaluation of the function of the lower urinary tract and are often used to determine the source of lower urinary tract symptoms including urinary incontinence, urinary frequency and urgency and difficulty with bladder emptying. When combined with imaging, video urodynamics give the clinician the most comprehensive evaluation of lower urinary tract function. Urodynamics consists of different tests that may be used individually or in combination depending on a patient’s symptoms. They can focus and urine storage or emptying or both. Urodynamic studies include:
Uroflowmeter: measures the flow rate of urine to determine both the speed at which it is released (average and peak rates) and to see how long it takes to get to its fastest point. An abnormal result suggests a weak bladder muscle or obstructed urine flow. Uroflowmetry is non-invasive and done in a private setting with the patient seated on a specialized toilet.
- Measurement of Post-Void Residual: Post void residual is the amount of urine left in the bladder after urination. This is usually measured with a hand held ultrasound or “bladder scan”. Occasionally it may be necessary to insert a small catheter into the urethra to collect and measure the urine volume.
- Multichannel Urodynamics: a comprehensive test of lower urinary tract function that is reserved for more complex cases of lower urinary tract dysfunction. It involves placing a small catheter into the bladder to both fill the bladder and measure the pressure in the bladder, and a second catheter in the rectum or vagina to measure abdominal pressure. Sometimes small sticky patches are placed around the anus to measure the muscle activity of the pelvic floor. From this the following tests can be done:
- Cystometry or cystometrogram (CMG): Bladder pressure is measured during bladder filling and during provocative maneuvers such as coughing or straining. This part of urodynamics is particularly useful to evaluate urinary incontinence and urinary urgency and frequency.
- Pressure-flow studies: Bladder pressure and urine flow rate are measured during voluntary urination. This part of urodynamics assess how the bladder empties itself and whether the bladder is weak or whether a blockage or obstruction exists in the urinary tract. This is usually done right after the CMG is completed.
- Urethral pressure profile: This part of urodynamics specifically evaluates the pressure in the urethra by slowly withdrawing the bladder catheter. It is sometimes used to assess urinary incontinence.
- Electromyelogram: An electromyelogram (EMG), assesses the pelvic floor muscles during bladder filling and emptying. The small patches that are placed around the anus will pick up electrical signals that signify muscle activity.
- Videourodynamics: With videourodynamics X-rays are taken during the above tests. Instead of filling the bladder with water, a contrast material is used to visualize the bladder and urethra during bladder filling and emptying. Videourodynamics gives the most comprehensive evaluation of the lower urinary tract.
At the Center for Women's Pelvic Health at UCLA we have a state-of-the art urodynamics testing facility. More importantly, we have an experienced staff of professionals with many years of experience in performing and interpreting urodynamics studies. Our physicians have written extensively on urodynamic techniques and interpretation. We understand the importance on maintaining patient privacy and dignity during testing that may be perceived as embarrassing. We are also aware that many patients who undergo urodynamics have physical limitations and we have experience in customizing testing for those patients to make the experience as pleasant as possible. Similarly, we are attentive to those patients who are particularly anxious about the testing. We believe that it is very important that patients understand what is being done, why it is being done, and how it will affect their management.