Urodynamic Testing

Original Editor - Khloud Shreif

Top Contributors -  

Introduction[edit | edit source]

Urinary System (Female).png

Urodynamic tests used to assess to what extent the bladder and urethra work efficiently to hold the urine, evacuate, and how they work, used in assessment some pathological urinary symptoms conditions such as: UTI, incontinence, frequent urination, the test illustrates the definite cause of the condition to be tested, and confirmation of the pathology the patient complains of. hence appropriate treatment will be provided. Urodynamic test carried at urodynamic laboratory units called conventional urodynamic test that depends on the artificial bladder filling and the ambulatory test carried outside the clinical setting and based on natural bladder filling[1]. It used in the following conditions:

Diagram showing prostate cancer pressing on the urethra CRUK 182.svg.png
  • It measures the pressure around the sphincter, the flow rate, and muscle function, and nerve as in patients with spinal cord injury.
  • Mandatary with young and elderly males with lower urinary tract infection and don’t respond to treatment to understand the underlying pathophysiology[2].
  • There is limited use with women with pelvic organ prolapse, which can be applied if the physician wants to correct the urethra with prolapse operation[3].
  • Women with incontinence, urine leakage
  • Patients with spinal cord injury, according to the level.
  • Detruosor overactivity.
  • Bladder pain
  • Problems to start urination and to problems with fully emptying the bladder.

Preparation for the test[edit | edit source]

Ask the patient to attend the clinic with a full bladder if you are going to do uroflowmetry, then change clothes to gown, then sit on the urodynamic chair for the test which used to measure the flow rate of urination.

The test used with the patient depending on the patient's complaint.

The patient doesn't use laxatives before the procedure to avoid undesired bowel movements, while enema may be used before the test if the patient has chronic constipation.

The saline is at room temperature (20 °C). 

Uroflowmetry test[edit | edit source]

UF test common to be used with outlet bladder obstruction, the patient asked to sit on the urodynamic chair and asked to urinate to evacuate his/ her bladder in special equipment, that is used to measure the flow rate and connected to the computer giving a graph of the results[4].

During this test using simultaneous assessment for bladder and pressure of the rectum will help to identify the reason for abnormality if it is ms weakness or obstruction, difficulty in urination, if there is a blockage, for example, prostate enlargement.

As the feeling of a full bladder is subjective from one to another, inserting 1.5 ml of water within 1 hour after full urination is more objective and more reliable[5].

Postvoid residual volume measurement[edit | edit source]

PRV is the remnant volume of urine in the bladder after active full urination, used with patients with overflow incontinence, it is common in the elder than an adult, or conditions with unobvious cause, to detect the ability of the patient to fully evacuate the bladder or not. After urination, a small flexible catheter inserted in the bladder for a full evacuation and may be measured by the US on the bladder.

PRV 100-200 ml needs attention and considered indeterminate, measurements need to be repeated at another time, while more than 200ml considered overflow rate[6].

Cystometry/ multichannel Cystometry.[edit | edit source]

It is an artificial bladder filling with saline, used to measure: how much the patient can hold, when will you feel the need to urinate, detect the leak point pressure, bladder capacity, and detrusor activity.

Procedures[edit | edit source]

Two flexible catheters the first one inserted into the bladder, while the second into the rectum to measure the pressure from the abdominal muscles, With two small electrodes around the rectum to measure pelvic floor muscle activity during the procedure.

During the application ask the patient for any feelings of pain or feeling of fullness; then ask to cough against a clothed mouth, or stand and do squatting according to the patient's tolerance and ability to control his bladder, these are provocation manoeuvers used to provoke detrusor overactivity.

The test stop when the patient feel strong desire to empty the bladder.

Last step the patient sits on the urodynamic chair and then normally evacuates the bladder while the pressure of the bladder, flow rate are recorded[1].


It is not necessary to use an antibiotic course before the test as the catheter inserted for a short time, it may be used after the procedure if the physician see signs of UTI during follow-up[8].

References[edit | edit source]

  1. 1.0 1.1 Vignoli G. Invasive Urodynamics. InUrodynamics 2017 (pp. 81-127). Springer, Cham.
  2. Jiang YH, Kuo HC. Recent research on the role of urodynamic study in the diagnosis and treatment of male lower urinary tract symptoms and urinary incontinence. Tzu-Chi Medical Journal. 2017 Apr;29(2):72.
  3. Ballert KN. Urodynamics in pelvic organ prolapse: when are they helpful and how do we use them?. The Urologic Clinics of North America. 2014 May 22;41(3):409-17.
  4. Sorel MR, Reitsma HJ, Rosier PF, Bosch RJ, de Kort LM. Uroflowmetry in healthy women: A systematic review. Neurourology and urodynamics. 2017 Apr;36(4):953-9.
  5. Ceyhan E, Asutay MK. Standardization for reliable uroflowmetry testing in adults. LUTS: Lower Urinary Tract Symptoms. 2021 Jan;13(1):45-50.
  6. Khandelwal C, Kistler C. Diagnosis of urinary incontinence. American family physician. 2013 Apr 15;87(8):543-50.
  7. Marc van Gurp. Urodynamic test. Available from: http://www.youtube.com/watch?v=oWJMjWqF7lQ[last accessed 26/3/2021]
  8. Foon R, Toozs‐Hobson P, Latthe P. Prophylactic antibiotics to reduce the risk of urinary tract infections after urodynamic studies. Cochrane Database of Systematic Reviews. 2012(10).