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Urodynamic Studies

This is a test to assess bladder function during filling and urination to determine the cause of your urinary symptoms. Understanding the cause of your urinary symptoms will often help choose the most appropriate treatment. Dr Nathan also usually performs a flexible cystoscopy immediately after this test to visually inspect the bladder.

What happens on the day of the procedure?

The test is performed as a day case and usually takes 30-40 minutes. A general anaesthetic is not needed as there is usually no associated pain and at most only minimal discomfort. Also, you need to be awake and co-operative during the test.

You do not need to fast before the test. You are advised to attend for the test with a comfortably full bladder. If you are taking any medication specifically for bladder or prostate symptoms, such as Flomaxtra, Duodart, Ditropan, Detrusitoal, Betmiga, or Vesicare, you will be asked to stop taking these at least 2 weeks before the test. However, you should continue taking all your other medications. Pease contact Dr Nathan's rooms if you are unsure which medications you need to stop and which you can continue. Also you will have been asked to complete a bladder diary and symptom questionnaire before the test.

Details of procedure

  • The test will be supervised by Dr Nathan, who will be assisted by nurses and sometimes a radiographer if x-ray pictures need to be taken.
  • First a urine flow rate measurement is performed- you will be asked to urinate into a flow rate machine to measure the strength of your urinary stream. A ultrasound scan will then be done to assess how well you emptied your bladder.
  • You will then lie on a couch or bed and a fine soft plastic catheter (tube) will be inserted through the urethra into the bladder using local anaesthetic jelly to help it slide in with minimal discomfort. The catheter is used to fill your bladder and measure the water pressure in the bladder.
  • A second fine catheter is placed in the back passage (rectum) to measure the pressures in the abdominal cavity.
  • Once all the catheters are in place, they will be taped to your leg and connected to transducers that continually measure the pressures, and relay the information to specialised computer software for recording and analysis.
  • The bladder is then filled slowly with sterile saline through the catheter.
  • You will be asked to cough and strain during the test, and to tell us when you feel the first desire to pass urine.
  • If one of your symptoms is urinary incontinence (leakage), we will try to reproduce this using a variety of measures. Do not be embarassed about this; reproducing your symptoms will help us determine the cause of your problem
  • You will be encouraged to hold on until your bladder feels very full.
  • To finish the test, we ask you to stand or sit and pass urine into the flow rate machine again.
  • We then remove all the catheters.
  • At this point a flexible cystoscopy is usually performed to visually inspect your bladder.

Analysing the study does take time so you will have a follow up appointment with Dr Nathan at a later date to discuss the results. The urodynamic test will help determine the cause of your urinary symptoms and will greatly assist in choosing the most appropriate treatment.

What are the risks of the procedure?

All procedures have potential side effects. Although these complications are well recognised the majority of patients do not have problems after this procedure


  • Some mild discomfort or burning sensation when passing urine for a few days.


  • Some mild bleeding in your urine.


  • Infection in your urine requiring antibiotics or very rarely septicaemia requiring hospital admission.
  • Inability to pass the catheter into your bladder so the test has to be abandoned and further tests need to be arranged.
  • Urinary retention - inability to empty your bladder - requiring a temporary catheter to be re-inserted into your bladder to relieve discomfort.
  • Failure to find the cause of your symptoms requiring a possible repeat of the test.

What can i expect when I get home?

  • You should drink about double your normal fluid intake for 24-48hr to help reduce the risk of infection.
  • A course of antibiotics may be given if you are thought to be at high risk for a urinary infection.
  • Arrange a follow up appointment to discuss the results.