During the test, a child's urine flow is measured in a special, privately placed toilet. Then the bladder is catheterized and filled slowly with a warm saltwater solution. At the same time, bladder pressures are monitored and the presence or absence of premature bladder contractions is noted. Other aspects of the bladder that are monitored include: bladder filling pressure, the sensations experienced by the child and emptying characteristics of the bladder (whether or not the bladder empties completely with normal pressures, high pressures or low pressures.) A Urodynamics study is usually performed when the following conditions are suspected or diagnosed: extrophy, myelodysplasia, neurogenic bladder, posterior urethral valves, spinal cord trauma, some types of urinary tract infection, and voiding dysfunction.

The study can have as many as five parts including:

For children with recurring urinary infection, urodynamics studies are usually performed after the child has been on continued long-term antibiotics, but is still having episodes of incontinence or recurring infection. The study may also be necessary when X-ray imaging reveals particular abnormalities of the bladder in children who have had multiple urinary infections.

For children with obvious neurological conditions, such as myelodysplasia, the studies are usually performed during the newborn period, to help your baby's pediatric urologist initiate therapy to prevent symptoms of the condition. The doctors will also want to use the test to assess the baby's neurological status because, as the child grows, there may be progressive changes in the neurological function of the bladder stemming from the spinal cord. As a result, if there are concerns over the spinal cord, the studies are usually repeated periodically. Studies are also needed when these children are older, if they haven't achieved continence with simple measures of intermittent catheterization and drugs that help paralyze the bladder.

Studies may also be performed when imaging studies reveal changes in the appearance of the upper urinary tract, which suggests an alteration in bladder function. In children with other anatomic conditions that lead to incontinence, such as bladder exstrophy/epispadias or anorectal malformations, urodynamics studies are necessary as soon as the diagnosis is made and after initial treatments fail to correct the incontinence. Testing helps guide the pediatric urologist toward other means of therapy and improves the efficiency of your child's treatment plan.

It is also important to prepare your child with information explaining why the test is important, what it hopes to accomplish, and how it might better your child's medical health. Information on the various aspects of the study is usually sent directly to your home. The nurse who greets you in the urodynamic suite will again explain all portions of the testing to you and your child. Understanding the purpose of the test and all of its aspects is likely to make it easier for your child to undergo the test.