Urodynamics Assessment

An urodynamic study examines how the bladder, sphincter, the muscle surrounding the neck of the bladder, and the urethra, the tube that carries urine out of the body, are working. The test can help determine the cause of bladder problems such as incontinence, or difficulty in passing urine. An urodynamic study is usually only done if other tests or treatments have failed.

The study is usually done as an out-patient procedure and the results will help decide if alternative treatment or surgery is needed. It usually takes 15-30 minutes and may be uncomfortable at times.

Before the study takes place the patient may be asked to keep a diary.  The patient will need to record what fluid is consumed, when and how much, how often urination takes place and how much. Also, a record of when an urgent need to urinate or a leakage has occurred.

During the procedure the patient will lie on a movable X-ray table, and two catheters will be inserted into the bladder through the urethra.  These catheters will measure how much liquid the bladder can hold and the pressure inside the bladder. A third catheter is placed in the vagina (female patient) or rectum (male patient) and this will measure the pressure the body is putting on the bladder.

Once the catheters are in place the bladder will slowly fill up with sterile water containing an X-ray contrast dye. During the test the patient will be asked to cough, strain or squeeze to check how the bladder reacts under pressure. Also, the patient will need to inform the consultant when they feel they need to urinate.

The patient will then empty the bladder so that the catheters can measure the flow rate and pressure of urination. At the end of the test, the catheters will be removed. 


This procedure is considered a safe procedure, and the benefits of a clear diagnosis greatly outweigh the disadvantages. Patients may experience some mild discomfort when urinating after the catheters are removed, and may have some blood in the urine. This should settle a day or so after the procedure. The consultant will explain the risks of the procedure in detail.