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About the Evaluation

Urinary Retention

If you've tried several treatments for urinary retention without success, don't lose hope. Medtronic Bladder Control Therapy may be an option for you.

With Medtronic Bladder Control Therapy's two-step process, you can test it out to see if it will work for you before making a long-term commitment. The testing period is called an "evaluation" or a "trial assessment."

Your doctor will discuss the evaluation procedure with you and the options for using either a temporary lead (a thin wire) or a long-term lead for the evaluation.

Determining Success

You and your doctor will decide together whether your evaluation was successful. The evaluation is considered a success if you experience a significant reduction in your symptoms.

For example, your evaluation may be considered a success if you used a catheter 5 to 6 times per day before the evaluation and 3 or less times per day during the evaluation.

The Evaluation Process

The evaluation starts with a minimally invasive outpatient procedure usually done in your doctor's clinic or in Day Surgery.  It usually takes about 20 minutes.

For the basic evaluation, which uses a temporary lead, your doctor will numb a small area of your upper buttock and insert a thin wire near your sacral nerves, located near the tailbone. The advanced evaluation uses a long-term lead that is fully implanted; one end of the lead is inserted near your sacral nerves. With both types of evaluations, the lead is connected to a small, external neurostimulator that you'll wear on your waistband. The neurostimulator generates mild electrical pulses that are carried to the sacral nerve by the lead.

The length of the evaluation may vary among doctors and depends on the type of evaluation you undergo. Generally, if the temporary lead is used, the evaluation period lasts from 3 to 7 days; if the long-term lead is used, the evaluation period may last up to 14 days.

Complications can occur during the evaluation, including movement of the wire, technical problems with the device, and some temporary pain. In most cases, these issues can be resolved, so talk to your doctor about your experience. (See Important Safety Information for possible adverse events.)

During the evaluation, you will need to use a symptom tracker to write down your urinary symptoms, such as how many times you catheterise and whether you have leaks. You should be able to work and continue your normal activities, as long as you avoid lifting, bending or twisting movements. If you experience a significant reduction in your symptoms, you and your doctor can discuss long-term InterStim™ Therapy.

Support During the Evaluation

Your doctor will be your primary source for support and information during the InterStim™ Therapy evaluation. In addition, for support during the evaluation, Medtronic offers a Technical Support helpline for people going through the evaluation.  You can contact the Helpline on 01923 205101.


Information on this site should not be used as a substitute for talking with your doctor. Always talk with your doctor about diagnosis and treatment information.