Sacral Nerve Stimulator: A pacemaker for the bowel and bladder
What is it?
A sacral nerve stimulator is a surgically implanted device used to help a patient reduce the number of bowel accidents (fecal incontinence). The device has several components: a neurostimulator which delivers electrical impulses to the sacral nerve; an electrical lead which is threaded through the sacrum and implanted adjacent to the sacral nerve; and a programmer that is used to control the electrical impulses delivered by the neurostimulator. The neurostimulator and the lead are permanent implants. The programmer is a handheld device that is not implanted. The device is identical to one already approved for the treatment of urinary incontinence.
When is it used?
A sacral nerve stimulator is used to treat chronic fecal incontinence in patients who have failed or could not tolerate more conservative treatments.
How does it work?
Although exactly how the device works is unclear, doctors believe the electrical stimulation improves the quality of the signal transmitted by the brain to the organs controlled by the sacral nerve, including the bladder, urinary and anal sphincters, pelvic floor and rectosigmoid colon.
How is it implanted?
Patients who may benefit from long-term implantation are identified during a two-week trial period in which just the electrical lead is threaded through the sacrum to the sacral nerve. The lead is connected to an external neurostimulator. Patients record the number of bowel accidents they have during the two-week trial period. If their bowel accidents decline by at least 50 percent, the patient can opt to have the neurostimulator implanted in the body for long-term therapy.
In the second procedure, the sacral nerve stimulator is implanted under the skin of the upper buttocks and connected to the electrical lead. An external handheld device is used to control the electrical impulse generated by the sacral neurostimulator.
What type of follow-up care is required for this device?
The settings on the handheld device can be adjusted to optimize treatment for each patient. Also, just like a pacemaker for the heart, the device is powered by a battery. Eventually, the battery will need to be surgically replaced – how long the battery lasts depends on the stimulation settings used and how often the neurostimulator is on. Most batteries require replacement after three to five years of use.