Urodynamics is a study that assesses how the bladder and urethra are performing their job of storing and releasing urine.
Urodynamics can help explain symptoms such as incontinence, frequent urination, sudden, strong urges to urinate, problems starting a urine stream, painful urination, problems emptying the bladder completely, night time frequency and leakage and recurrent urinary infections.
The complex graphs and neuromuscular function values that are generated during the study will provide the physician with the information necessary to diagnose the cause and nature of the patient's urologic complaints, allowing the doctor to offer the most effective treatment options available.
How is the Urodynamic study performed?
A urodynamic study begins by having the patient urinate above an uroflow meter. Patients who sit to urinate can use a chair over the uroflow, while those who stand to urinate are asked to urinate in a funnel above the uroflow container. The uroflow measures the amount of urine emptied and the rate of the urine flow over time.
Next, a urethral catheter is placed into the bladder. It is a very small and flexible tube that is connected to a pressure transducer to measure the pressure in the bladder. A thin, flexible catheter is inserted into the rectum as well. (Don't worry! You can't even feel it!) It too is connected to an outside pressure transducer to measure rectal pressure. Why do you need to know the rectal pressure when the study is for your bladder? Good question. The bladder pressure is affected by pressure due to the bladder muscle and outside abdominal pressure. By measuring this abdominal pressure via a rectal catheter, any pressure contribution from the abdomen can be subtracted in order to identify the pressure due to the bladder muscle itself.
Small adhesive patch electrodes are placed on either side of the patient’s perineum to measure pelvic floor muscle activity and sphincter functions of these muscles. The urethral sphincter is the specialized muscle around the urethra that keeps us from leaking urine. Once catheters and EMG patches are placed, the patient is either positioned standing or sitting over the uroflow. The bladder is then filled with water through the bladder catheter and the pressures during filling are monitored. The patient is asked several questions about sensation. At periodic volumes, the filling is stopped and the patient is asked to cough or bear down. These activities are used to identify and document urine leakage, and the leak point pressures that this leakage occurs. The patient's bladder is filled until she has reached her maximal capacity, and cannot hold anymore. She is then asked to urinate. In most cases, she will be able to urinate right around the urethral catheter, and pressures will be monitored during urination.
How long does it take?
The setup which includes catheter placement, connecting the transducer lines and setting up the machine may take 10 to 15 minutes. The urodynamic procedure itself may take 20 to 25 minutes.
Does it hurt?
Since the procedure requires a tiny catheter, the patient may experience mild urethral irritation. A small amount of blood is also common, but resolves within a short time. Preventive antibiotics are always given to avoid an infection, but one is still possible. Urodynamic studies are typically very well tolerated.