Urodynamic testing is a diagnostic tool used to measure how well the bladder and urethra function in storing and releasing urine. This series of tests provides objective data about the dynamics of the lower urinary tract. It helps doctors understand the physical reasons behind symptoms like urinary incontinence, frequent urination, or the inability to fully empty the bladder. The results are used to accurately diagnose conditions such as overactive bladder or urinary retention so that a specific treatment plan can be developed.
Preparing for the Procedure
Preparation for urodynamic testing is generally minimal, but following specific instructions from your clinic is important to ensure accurate results. You will typically be asked to arrive for the test with a comfortably full bladder, as the initial stage requires you to urinate. If a full bladder is difficult to achieve, some clinics may ask you to arrive early to drink fluids, but you should not over-distend your bladder.
You should confirm with your healthcare provider whether you need to stop any current bladder-specific medications before the test, as some drugs can interfere with bladder function measurements. In most cases, you can eat normally and continue taking all other routine medications unless otherwise directed. If your doctor requested that you complete a voiding diary, be sure to bring this record to the appointment.
The procedure cannot be performed if you have an active urinary tract infection (UTI), so you may be asked to provide a urine sample beforehand to check for infection. If a UTI is detected, the test will be postponed until the infection has been successfully treated with antibiotics. Following these instructions helps ensure that the test replicates your typical urinary function.
Step-by-Step During the Test
The urodynamic procedure begins with a test called uroflowmetry, which measures the speed and volume of your urine flow. You will be asked to urinate privately into a special device, similar to a toilet, which electronically records the flow rate over time. This initial measurement helps identify if there is any blockage or weakness in the bladder muscle affecting your stream.
After the uroflowmetry is complete, a thin, flexible catheter is gently inserted through the urethra into the bladder to drain any remaining urine, which is measured as the post-void residual volume. A smaller, specialized catheter is then inserted into the bladder and a second pressure-sensing catheter is placed into the rectum or vagina. These catheters are connected to a computer to continuously measure pressure inside and outside the bladder.
The main part of the test, called cystometry, then begins as the bladder is slowly filled with sterile water or saline solution through the catheter. As the bladder fills, the clinician will ask you to report your sensations, noting when you first feel the urge to urinate and when the urge becomes strong. This process measures the bladder’s capacity, its elasticity, and whether the bladder muscle contracts involuntarily, which can indicate an overactive bladder.
To mimic everyday activities that can trigger leakage, you may be asked to cough or strain while the sensors record the bladder pressure. This maneuver, known as a leak point pressure measurement, helps determine the type of incontinence you may have, such as stress incontinence. Finally, you will be asked to empty your bladder into the flowmeter again, with the pressure catheters still in place, for a pressure-flow study.
This final voiding phase measures the pressure the bladder muscle generates to empty itself and the resulting flow rate. In some cases, small electrode patches may also be placed near the anus to perform electromyography (EMG), which records the electrical activity of the pelvic floor muscles during filling and emptying. The entire process is not painful, though you may feel temporary discomfort or pressure from the catheters.
Immediate Aftercare and Understanding the Results
Once the catheters and electrode patches are removed, you can typically return to your normal daily activities immediately, as no sedation is used during the procedure. It is common to experience minor, temporary side effects due to the catheterization. These effects can include a mild burning sensation or soreness during urination, a slight increase in urinary frequency, or a trace amount of blood in the urine.
To help flush your system and minimize the risk of developing a urinary tract infection, it is recommended that you increase your fluid intake for the rest of the day. If the burning sensation lasts longer than 24 to 48 hours, or if you develop signs of infection such as a fever, chills, or foul-smelling urine, you should contact your healthcare provider immediately. These symptoms warrant prompt medical attention.
The results of the urodynamic study are not instantaneous, as the complex data collected requires careful analysis by the physician. The test provides detailed information about your bladder’s ability to store urine at low pressure, the strength of your bladder muscle, and the presence of any obstruction during voiding. Your doctor will typically schedule a follow-up appointment to discuss these findings, provide a definitive diagnosis, and outline the most appropriate treatment plan.