InterStim Implants for Urinary or Bowel Incontinence

Incontinence is often the result of a miscommunication between the brain and the bladder and/or bowels. InterStim therapy, a type of sacral neuromodulation (SNM) or sacral nerve stimulation (SNS) therapy, works to re-establish this very important communication channel. Incontinence Institute offers three implanted sacral neuromodulation devices: 

  1. InterStim II
  2. InterStim Micro
  3. Axonics

How does InterStim therapy work?

InterStim therapy works by stimulating the sacral nerves with tiny electrical pulses. In individuals experiencing urinary or fecal incontinence, the brain and the sacral nerves are unable to communicate properly. InterStim therapy attempts to better regulate the sacral nerves’ function, so the nerves can interpret signals from the brain and pass them on to the surrounding pelvic floor muscles. Mild electrical pulses help the nerves to function normally, much in the same way that a pacemaker uses electrical impulses to keep the heart beating on a steady, predictable rhythm. This restores normal bladder and bowel function.

As a result of the pulses from InterStim devices, the symptoms of an overactive bladder or bowel incontinence are effectively eliminated. 

These devices are an option for patients who have not responded to more conservative treatments such as changes to diet, medication and physical therapy.

What’s the process for getting an InterStim device?

Stage 1, trial period and evaluation:  InterStim therapy begins with a two-week trial period employing a wearable, external version of the device to determine if the treatment is likely to be effective for a patient. This is known as InterStim Stage 1. 

Stage 2, surgery: If the trial produces positive results, the device is implanted in a patient’s lower back near the sacral nerves. Surgery is known as InterStim Stage 2.

Post-surgery: After surgery to implant an InterStim device, the doctor will program the device’s electrical signals based on the results from the trial period. 

InterStim Therapy Trial Period

InterStim II and InterStim Micro offer a trial device that simulates the actual, implanted device. This is called InterStim Stage 1. Receiving the trial device is a 15-minute, minimally invasive outpatient procedure where the doctor places a lead connected to a small, externally worn device. The external device is worn underneath the patient’s clothing. 

Patients typically wear the trial device between 5-14 days to determine candidacy for a permanent device. During this time, patients log their symptoms to discuss with their doctors. They can continue about their normal activities and experience what it would be like to live with InterStim therapy, how it feels when activated, and if the permanent device will be able to reduce or eliminate their symptoms.

How is an InterStim device implanted?

InterStim placement is quickly and safely done at an outpatient surgery center. The procedure itself typically takes between 20-30 minutes to complete, and surgery is minimally invasive. This can often be done under local anesthesia, though some doctors will prefer to use general anesthesia. The device is inserted in the lower back, above the buttocks. 

Though insurance plans vary, Medicare and private insurance generally cover InterStim treatment, but please consult with your doctor and insurance company.

How long does it take to recover from surgery?

Patients typically return to their normal activities within three weeks following the InterStim procedure. Light activity is usually possible within a few days after surgery. 

What to Expect After the Device is Implanted

Most patients will notice a slight pulling or tingling sensation, according to Medtronic, which manufactures the InterStim devices. These sensations should not be painful — if they are, contact your doctor. Sudden movement can also cause a change in how the stimulation feels, because the device shifted in proximity to your sacral nerve. This doesn’t affect the effectiveness of the stimulation has changed. After a few weeks, patients typically report they don’t notice the sensation anymore. 

The goal is for InterStim therapy to help patients return to their daily routines without worrying about bowel or urinary incontinence. A successful procedure should help patients be more confident of their ability to go through life, taking long walks, traveling or visiting a movie theater. Things that were difficult become possible, once patients are no longer worried about incontinence. 

How do I program or manage an InterStim device?

Both InterStim devices come with a hand-held programming remote that allows patients to turn down or turn off the InterStim device if needed. Your doctor may also program the device to turn on and off at regular intervals, depending on whether you need constant stimulation. 

Will I be able to see the InterStim device through my skin?

No, you will not be able to see InterStim II or InterStim Micro devices through the skin once they’re implanted. 

Can the InterStim device be removed?

Yes, the device can be removed. In the unlikely event that the procedure is not effective, it can easily be reversed. Both devices eventually need to be removed and replaced; the recharge-free InterStim II needs to be replaced every 5 years, and the rechargeable InterStim Micro needs to be replaced every 15 years.

Can I have an MRI with an InterStim device?

Yes, InterStim devices are full-body MRI compatible. Please talk to your doctor for more details.

What are the differences between Axonics, InterStim II and InterStim Micro?

InterStim II

  • About the size of a silver dollar, 44mm x 51 mm
  • Doesn’t require recharging
  • Needs to be replaced about every five years

InterStim Micro

  • Smallest SNM device available, 17 mm x 47 mm
  • Requires charging for 20 minutes, once a week
  • Needs to be replaced about every 15 years

Axonics Therapy

  • About the size of a quarter, 23 mm x 45 mm
  • Requires wireless charging for about an hour, once a month
  • Needs to be replaced about every 15 years

InterStim Therapy for Urinary Incontinence

Urinary incontinence affects over 25 million Americans. A number of causes exist: injury or trauma to the pelvic region or back, enlarged prostate or prostate cancer, pregnancy or childbirth, neurological disorders, estrogen loss following menopause, other health conditions like multiple sclerosis or suffering a stroke. 

Take our Urinary Incontinence Self-Assessment

Effectiveness of InterStim Devices for Urinary Incontinence

According to studies in the Journal of Urology and Medtronic’s own InterStim Therapy Clinical Summary, 82% of overactive bladder (OAB) patients achieved therapeutic success with an InterStim device at five years of treatment. 

  • 59% of urge incontinent patients achieved greater than 50% reduction in leaks/day
    • 71% of those urge incontinent patients who reported heavy leaks at baseline achieved greater than 50% reduction in leaks/day
  • 45% of patients had no incontinence episodes at five years of treatment
  • 56% of urgency-frequency patients achieved greater than 50% increase in volume voided and improved degree of urgency

InterStim Therapy for Fecal Incontinence

According to a report from the University of Rochester, bowel incontinence affects as many as 18 million Americans. Aging or injuries incurred while giving birth are the most common causes for fecal incontinence. 

Take our Fecal Incontinence Self-Assessment

Effectiveness of InterStim Devices for Bowel Incontinence

In study results published in the medical journal “Annals of Surgery,” 120 patients and their doctors tracked the effectiveness of the therapy. 

  • About half of the patients experienced total recovery of bowel control and reported no incontinence problems for one year after the surgery 
  • 30% reported that their bowel leaks were reduced by more than 50%
  • InterStim therapy produced significant positive results for more than 8 out of 10 patients 

InterStim Therapy History

InterStim devices have been used to prevent urinary incontinence since 1997. In 2011, after extensive study, the Food and Drug Administration (FDA) also approved the use of the InterStim implant as a fecal incontinence treatment. Over 100,000 individuals have been treated with InterStim therapy.

Who is a good candidate for InterStim therapy?

InterStim can be a great option for patients who haven’t experienced success with treatments like supplements and dietary adjustments. Ideal candidates are men and women suffering from these conditions:

  • Overactive bladder
  • Urinary or bowel urge incontinence
  • Urgency-frequency
  • Non-obstructive urinary retention
  • Chronic fecal incontinence

But it’s not a good option for all patients, including patients who:

  • Lack the motor skills needed to operate the InterStim system
  • Are not good candidates for surgery
  • Suffer primarily from stress incontinence
  • Experience urinary retention due to benign prostatic hypertrophy (enlarged prostate)
  • Have cancer or urethral stricture

InterStim therapy may also not be a good option for patients who are pregnant, are under the age of 16 or who have neurological issues as a result of a chronic condition such as diabetes or multiple sclerosis, since the safety and effectiveness of the treatment has not been established in these populations.

If you’ve tried conservative approaches for your urinary or fecal incontinence and your symptoms still interfere with your daily activities, InterStim could be right for you. Contact our team of expert urinary and fecal incontinence doctors at our office in Nashville, TN.


To contact us or learn more, click here or call our discreet, dedicated Medical Concierge at 1.888.741.6403.

About The Incontinence Institute

At the Incontinence Institute, our team of healthcare providers understand the physical and mental trials that accompany living with urinary or bowel incontinence. Because of this, we are sensitive to your situation and treat all of our patients with the utmost respect and concern for discretion.


Individual incontinence conditions, treatment and recovery times may vary. Each patient's experience with incontinence procedures and / or surgery will differ. All surgical procedures involve some level of risk. If directed to pursue surgery by your physician, prompt action is advised, as waiting may reduce the efficacy of surgical treatment. The opinions expressed in patient testimonials are by patients only; they are not qualified medical professionals. These opinions should not be relied upon as, or in place of, the medical advice of a licensed doctor, etc.

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Incontinence Institute 2009 Mallory Lane, Suite 100 Franklin, Tennessee 37067

1.888.741.6403

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