Urodynamic testing

Urodynamic testing

A urodynamic test is done to get more information about your urination cycle and how your bladder muscles work. This test is called a filling and voiding cystometry.

If you are scheduled to undergo surgery for urinary incontinence, a urodynamic test may be done, especially if it is not the first surgery in your abdomen. The test may also be needed when your diagnosis is uncertain.

Your doctor may decide to give you this test if:

  • You have a neurological dysfunction
  • You have had pelvic or prostate surgery
  • You have much urine left in the bladder after urination
  • If benign prostatic enlargement is uncommon in your age group
  • If the urologist needs more information to understand the cause of your symptoms

During the test, your doctor inserts catheters in your urethra and rectum to measure the pressure in your bladder and abdomen. The bladder is slowly filled with sterile water through the catheter in the urethra. In this way, the filling of the bladder with urine is simulated.

When the bladder is full, you will urinate into a uroflowmeter (Figure 1). The test results are shown on a screen which is connected to the catheters. Sometimes the test has to be repeated to get accurate results but the catheters will already be in place for the second test.

Urodynamics can be combined with the use of x-rays or fluoroscopy. In this case, the bladder is filled with a liquid contrast dye. Your doctor may also decide to perform special tests such as electromyography, to look at signals to the pelvic floor muscles, urethral sphincter, and/or anal sphincter, or sensory testing of the bladder and urethra.

Some patients have a risk of sudden high blood pressure (autonomic dysreflexia) during urodynamic testing. This risk has to be managed. It is a sudden and exaggerated automatic response to various stimuli in patients with spinal cord injury or spinal dysfunction. The stimulus can be a full bladder or bowel. It can also result from sexual stimulation or pain, for example, an infected toe nail or a pressure sore. Sudden high blood pressure can be life-threatening if not properly managed.

Fig. 1: A common type of uroflowmetry container.
Fig. 1: A common type of uroflowmetry container.