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Sacral nerve stimulation and Interstim therapy


What is Overactive bladder?

Millions of people suffer from a bladder control problem known as overactive bladder. This condition involves the need to urinate frequently both day and night. While there are many treatment options available: antimuscarinic medications, behavior / dietary modifications, vaginal estrogen, and pelvic floor exercises, not all patients respond well to these therapies. InterStim is a third-line therapy used to control overactive bladder symptoms with an implanted device that stimulates the sacral nerve.

What is InterStim therapy?

Sacral Nerve Stimulation (SNS) is a minimally invasive surgical option that involves the implantation of a small medical device to stimulate the sacral nerve. The InterStim device was developed by Medtronic, and was approved for use by the U.S. Food and Drug Administration (FDA) in 1997.

The InterStim device sends mild electrical pulses to the sacral nerves located just above the tail bone. The sacral nerves activate or inhibit muscles and organs that contribute to urinary control. These include bladder, sphincter and pelvic floor muscles. This electrical stimulation is designed to facilitate communication between the brain and the bladder in order to eliminate, or reduce, certain bladder control functions.

Who are candidates for InterStim therapy?

Sacral nerve stimulation is intended for patients who have failed or cannot tolerate more conservative treatments. Bladder control problems that may improve with SNS therapy include:

  • Overactive bladder – Includes urge incontinence, urgency and frequency.
  • Urge incontinence – The involuntary loss of urine associated with a sudden, strong desire to void (urgency).
  • Urgency-frequency – Frequent, uncontrollable urges to urinate (urgency) and voiding often in very small amounts (frequency).
  • Urinary retention – The inability to empty the bladder.
  • Fecal Incontinence – The inability to control your bowels.

Patients who are not candidates for SNS therapy

InterStim Therapy is not intended to treat or be used by:

  • Stress incontinence – People with stress incontinence lose urine when they exercise, sneeze, cough, or laugh.
  • Mechanical obstructions – Enlarged prostate (benign prostatic hyperplasia or BPH), cancer or narrowing of the urethra (urethral strictures).
  • Patients with pacemakers.
  • Pregnant women.
  • Diabetic patients.
  • Patients with neurological diseases such as Multiple Sclerosis.
  • Patients under 16 years of age.

Sacral nerve testing

Before starting InterStim therapy, a provider will conduct two tests to determine if this therapy will be effective for the patient.

Basic Test

This is an in-office procedure in which temporary leads are placed into the sacral nerve using a local anesthesia. After the leads are placed, a test will be performed to insure that the sacral nerve is being stimulated. This can be easily verified by the movement of the big toe. Regardless of overall test outcomes, these leads will be removed in the office after one week.

Advanced Test

This test is performed in the operating room on an out-patient basis. This is generally indicated for patients who have urinary retention, in which a longer sacral nerve stimulation is necessary. Rather than placing temporary leads, this procedure uses one long-term lead that is left in the sacral nerve for a minimum of two weeks. If the patient is recommended for permanent placement of the InterStim device, this lead will remain in place and be connected to the InterStim after the test period is complete. If the patient is not recommended for the InterStim, they will still require a second surgery to remove the long-term lead.

Permanent placement of the InterStim device

Implantation of the InterStim device is performed in an operating room. The doctor will advise the patient which type of anesthesia will be used – pain medication with a sedative or general anesthesia. During the operation, two incisions will be made in the buttocks. The device will then be placed under the skin. The incision for the neurostimulator will be about 2 inches long; a second incision will be about ½ inch or less.

If a temporary lead was used for the test stimulation:

  • The lead will be removed.
  • A long-term lead and neurostimulator will be implanted in the upper buttock or abdomen.

If a long-term lead was used for the test stimulation:

  • The long-term lead will remain in place.
  • The external wire used for test stimulation will be removed.
  • A neurostimulator will be connected to the long-term lead and placed under the skin in the upper buttock or abdomen.

Limitations to sacral nerve therapy

Some known limitations for this therapy include:

  • Failed test stimulation.
  • Inability to use the patient programmer.

Is sacral nerve stimulation a cure for bladder problems?

As with any therapy, individual results may vary. Patients implanted with an InterStim device can experience the relief of many urinary symptoms, as well as an improved quality of life. However, implantation of the device is not guaranteed to result in complete improvement or cure.

If you are experiencing the symptoms of overactive bladder, contact Urology Austin to schedule an evaluation by one of our urologists.

Dr. Rachel Sosland, Board Certified Urologist at Urology Austin, is interviewed by KXAN TV about common urological conditions that effect millions of Americans. Dr. Sosland discusses the symptoms and treatment options for urinary incontinence (stress incontinence), overactive bladder and urinary retention. She also talks about third-line therapies such as botox injections, InterStim Sacral Nerve Stimulation, and Percutaneous Tibial Nerve Stimulation (PTNS).


Bladder Control Webinar

Dr. Rachel Sosland, Urologist with Urology Austin, presents a webinar titled “Live Without Limits – Understanding Treatments for Bladder Control”. This webinar covers the diagnosis and treatment options for overactive bladder, stress incontinence and urinary retention. This webinar was co-hosted by Medtronic on May 10, 2022.




Related link

Medtronic Patient Education

InterStim video courtesy of Medtronic, 2022

Video courtesy of Medtronic, 2021. Please note: this video references both urinary and fecal incontinence. Urology Austin does not treat fecal incontinence, only urinary incontinence.

Video courtesy of Medtronic, 2022

Video courtesy of the National Association for Continence