Cystometrogram (CMG) / Urodynamics

In patients with complex urinary issues, or in patients who are considering some types of surgery, CMG testing is completed to establish a baseline of a number of important factors. These include confirming normal capacity and function of the bladder and ruling out overactive bladder that could adversely affect the outcome of some types of surgery.

Cystometrogram Procedure

This test usually takes about 45 minutes to complete. Our patients come to the office and leave a urine specimen to rule out infection. A bladder ultrasound is usually completed to confirm that the bladder is empty at the start of the procedure. The patient is positioned on a special chair, and the nurse places very small catheters into the bladder and the anus. There are sensors that are taped to the buttocks so that we can monitor muscle contractions. The bladder is then slowly filled with sterile water, and the nurse will monitor how your bladder reacts during filling and voiding. Afterwards, the catheters are removed. There is no anesthesia or IV that is necessary during this procedure.

Cystometrogram Risks

The only risk of a CMG is urinary tract infection that can occur after the catheter is placed. Patients are given an oral antibiotic to prevent this from occurring. To prepare you will be given instructions at the time that this procedure is scheduled. When you arrive at the office for the test, the nurse will check your urine. There are some bladder medications that we may ask you to stop taking a few days prior to the procedure as they may affect the results. If possible, try to have a bowel movement the morning of the procedure.