Urodynamic studies (sometimes referred to as videourodynamics) are a very accurate and sensitive investigation performed to determine how well a person can urinate and how well the bladder functions in its ability to store urine. It may be performed after other simpler tests have shown no abnormality, in patients who have urgency (must pass urine suddenly), stress incontinence (pass urine with laughing or lifting), excessive frequency of urination, difficulty in passing urine or a poor flow of urine.
The patient starts the procedure, usually undertaken in an x-ray centre, with a full bladder. The patient is asked to pass urine into a funnel attached to a machine, which measures the rate at which the urine flows. This is done seated in women and standing or seated in men.
The patient then lies down, and a thin pressure sensitive tube (catheter) is passed through the urethra and into the bladder. Any residual urine in the bladder is removed and measured, and the muscular pressure in the bladder is measured. The bladder is then filled through the catheter with an x-ray visible dye. The patient is asked to note when they experience a normal desire to pass urine, and an urgent desire to pass urine, and the pressure is measured at each stage. An x-ray is also taken at each stage to show the degree of filling and shape of the bladder.
The patient then stands, or the table is tilted upright, the catheter and pressure measurer are removed, and the patient passes urine while an x-ray is taken. Those with stress incontinence may be asked to cough before the urine is passed while another x-ray is taken to detect any urine leak. This can help determine why the leakage of urine is occurring.
In some women, ultrasounds are used with a probe in the vagina rather than x-rays.
The test may be uncomfortable and embarrassing, but not painful. There may be some blood in the urine for the next day or so. The only significant complication may be the development of a urinary infection, but this may be prevented if an antibiotic is given during the procedure.