Greater Boston Urology Blog

What Are Urodynamic Studies?

If your medical provider orders urodynamic testing, you will, no doubt, have many questions. What are urodynamic studies anyway? How should you prepare? Will it hurt? When can you expect results? 

Below, we asked one of our nurse practitioners, Meagan Smoyer, to answer these and other common questions about urodynamic studies.

As with all content on our blog, the following is meant to be educational in nature, not medical advice. Always consult your physician regarding your unique healthcare needs.

What are urodynamic studies?

MEAGAN SMOYER: Urodynamic studies (UDS) are a series of tests that evaluate how well your bladder, urinaryheadshot of nurse practitioner Meagan Smoyer, a white woman with shoulder-length blonde hair sphincter, and urethra hold and release urine. These tests can show how well the bladder works and why there could be bladder leaks or blockages. 

These tests are done via small catheters placed in the bladder and either the vagina for women or rectum for men along with electrodes placed on your skin near the rectum. Basically, the testing evaluates how well the bladder fills and empties. 

What are the different types of tests?

MEAGAN SMOYER:  Here are the series of tests that make up a urodynamics study:
●    Cystometry
●    Electromyography
●    Leak point pressure testing
●    Post-void residual
●    Urethral pressure profile
●    Uroflowmetry
●    Voiding pressure study

During a traditional urodynamics study, the filling medium for the bladder is water or saline solution. 

There is also a video urodynamic study. During a video urodynamics test, radiographic contrast agents are used. Video urodynamics requires a more expensive and elaborate setup and specifically trained clinicians. The procedure also typically takes much longer than traditional urodynamic studies. Pregnant women are not able to have video urodynamics completed. 

Video dynamics can provide additional important details about a patient’s condition. It is a real-time measurement of bladder pressure during urinary leakage and helpful particularly in the case of incontinence or bladder obstruction. It also shows important images that can help pinpoint more uncommon problems. 

When would urodynamic studies be ordered?

MEAGAN SMOYER: These studies are ordered to find the cause of problems related to any type of urine leakage, urgency, frequency, incontinence, problems starting urination, not emptying your bladder all the way, weak urine stream or flow, or frequent urinary tract infections.

How do the various urodynamic tests work? What happens during each procedure?  medication?

MEAGAN SMOYER: The series of tests that make up a urodynamic study include the following: 

Cystometry is used to measure how much urine the bladder can hold. It also measures the pressure inside the bladder, and how full it is when you have the urge to go.

Electromyography tests the electrical activeness of the muscles and nerves in the pelvic floor. Small, sticky sensors are placed near the rectum to record muscle and nerve activity. 

Leak point pressure testing is used to diagnose stress incontinence. This shows if any urine leaks during stress (e.g., cough, laugh, sneeze) and at what point your bladder expels urine.

Post-void residual measurement is the amount of urine in the bladder after you urinate. Everyone has a small amount of urine in the bladder after urination. However, if you have 6 or more ounces in your bladder, then it is not emptying well. 

Urethral pressure profile is not commonly done by urologists, but it can be done to learn more about the strength of your urethra and its outlet. A catheter with a sensor is moved back and forth in the urethra and then records information about the urethra and outlet. 

Uroflowmetry measures the flow of urine. It shows how much urine comes out, how fast, and how long it takes. It’s a diagnostic test to assess how well the urinary tract functions. It can provide information on a blockage such as an enlarged prostate. 

Voiding pressure flow study measures the pressure in your bladder as you urinate along with the urine flow rate. It helps to find a block in the bladder (for example, from prostate enlargement) or when combined with the CMG, it may identify a weak bladder or another issue. 

After you report reaching full bladder capacity, you urinate into a funnel on a special chair used for urodynamics. You urinate with the void pressure catheter or “manometer” still in place. Urine easily flows around the small catheter, and it measures how well your bladder muscles work as it empties.

Is urodynamic testing done in the office or a hospital?

MEAGAN SMOYER: At GBU, we perform the testing in our Care Centers. It can be done at a healthcare provider's office, radiology center, or hospital.

How do patients prepare for urodynamic testing?

MEAGAN SMOYER: There is no special planning per se. I ask patients to read over any informational materials that they have been provided. We also ask that patients drink fluids to have a comfortably full bladder before their test. 

Who can perform urodynamic studies? 

MEAGAN SMOYER: Urodynamics can be performed by physicians, physician assistants, nurse practitioners, nurses, or medical technicians or a medical professional who has been trained for urodynamics. A physician must review and interpret the results if done by a nurse or medical technician. 

Is the procedure the same for women and men?

MEAGAN SMOYER: Men and women have a small catheter placed into the bladder via the urethra. The only difference really is that for women, we can use the vagina or rectum to place the small catheter that measures abdominal cavity pressure. For men, we use the rectum.

How long does a urodynamic study take?

MEAGAN SMOYER: The time will differ slightly for each patient based on how the bladder responds during the filling and emptying phase. I tell patients to allow for about 45 minutes. The actual test does not take this long. The set up for testing is what takes the longest time as we want to have the catheters correctly placed for the most accurate results.

Is a urodynamic test painful?

MEAGAN SMOYER: Most patients say it is slightly uncomfortable, but it should not hurt or be painful.

Are the results of the urodynamic test immediate?

MEAGAN SMOYER: This can depend on who performs the test. The results may need to be reviewed by a provider, which can take a few days to process and interpret the results. We usually schedule a follow-up visit to discuss the full results of testing, diagnosis, and next steps for treatment.

How long does it take patients to recover from the procedure? Can they drive home the same day, will they be in any pain, are there any restrictions?

MEAGAN SMOYER: Patients can drive themselves home after urodynamics testing. Some patients may feel mild discomfort, burning, or soreness with urination. Patients may see some blood in the urine. If present, these symptoms usually self-resolve in 1-2 days. 

I encourage patients to drink 8-16 ounces of water every 1-2 hours after the procedure. If necessary, patients can take over the counter pain medications. Sometimes taking a warm bath can help with any mild discomfort or using a warm, damp washcloth over urethral opening. If a patient continues to see blood in the urine, develops fevers, chills, or worsening pain, they are instructed to call the office to notify the provider.

Most urodynamic tests have no risk of complications. If you had a catheter inserted into your bladder, you may have a slight increased risk of developing a bladder infection.

Is there anything else you want to make sure our readers keep in mind about urodynamic testing?

MEAGAN SMOYER: Don't be scared! Most patients have a lot of anxiety about the test itself, but afterwards tell me it was not as bad as they had anticipated. I personally do my best to make patients feel comfortable and informed. Urodynamics is a valuable test to evaluate how your bladder empties and fills. This information will allow us to suggest the best treatment options based on your specific bladder findings. 

If you're dealing with bladder dysfunction, we can help. 

Our world-class physicians, nurse practitioners, and physician assistants can help diagnose and treat your bladder dysfunction. Request an appointment and let us help.


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