In the Neurourology Unit at Boston Children's Hospital, we carefully tailor our diagnostic testing to each patient so we can provide not only accurate diagnosis, but an understanding of the underlying reasons for your child's urinary tract condition.
- monitoring the dynamics of the bladder function during its two phases of storage and evacuation
- measuring the neuromuscular activity of the urinary sphincter as the bladder cycles through these two phases.
When appropriate, a urinary flow rate is done, which is a test that displays the characteristics of the flow curve and residual urine volume after voiding is obtained.
From the findings obtained during the urodynamic testing, recommendations are made to one of our staff urologists or a pediatric specialist within Children's, or the primary care physician who referred your child to us.
Cystometrogram CMG - This test is done by inserting a small catheter into the bladder through the channel that the child urinates through. The bladder is then filled slowly with warm (body temperature) salt water, while the bladder pressures are monitored. Any changes in the pressures are noted and when the child voids (urinates) or feels full the infusion is stopped. If the child can void, he is asked to do so. Then and the rest of the urine left in the bladder at the end of voiding is measured. Any remaining fluid is drained before the catheter is removed.
Sphincter Electromyogram EMG - During this test, a very small needle is passed through the skin, under the genitalia, until it reaches the urethral sphincter muscle (the muscle which we tighten to prevent from voiding and relax when we want to urinate). An EMG machine displays the electrical potentials generated by the muscle when it contracts. Various reflexes are tested, and the response of the sphincter to voluntary tighten or relax (if possible) is recorded. The sphincter muscle EMG is also monitored continuously during filling and emptying of the bladder. From these results, we can determine the stimulation of the muscle by the nerves coming from the spine, and whether or not there is control over this muscle from the brain.
Urinary Flow Rate - If your child is able to void (urinate) on his/her own, then she will be asked to urinate into a special flow meter that is located in a private bathroom. This meter is connected to a machine that records the characteristics of the flow. Once the child has completed voiding, the residual urine is evaluated in one of two ways:
- A bladder scanner is placed on the lower abdomen that sends sound waves to and measures the volume retained in the bladder.
- The child is catheterized for the CMG test and the residual urine is drained and measured.
Read more about Urodynamics Testing
How to prepare for urodynamic testing
If your child is taking medication specifically designed to alter bladder function, a normal dose of that medication needs to be taken two hours before the scheduled start of the test. If your child is on any other medications for other conditions, this information needs to be told to the nurses who give the urodynamic test.
Before the test, the urodynamic nurses will explain the reasons for the test, what you and your child can expect during the test, and how your child will feel afterward. For the most part your child will feel fine after completing the study testing, but may experience a slight amount of burning the first time or two they urinate afterwards.
All tests can be done during a day appointment. The time needed to complete the test varies. In general, the testing takes less than one hour.
If you have any questions before or after your child's test(s), we welcome you to call our urodynamic nurses at 617-355-4889. The urodynamics testing is located on Pavilion 2.