This is a brief overview of information related to FDA’s approval to market this product. See the links below to the Summary of Safety and Effectiveness Data (SSED) and product labeling for more complete information on this product, its indications for use, and the basis for FDA’s approval.
Product Name: InterStim® Therapy System
PMA Applicant: Medtronic Inc.
Address: 710 Medtronic Parkway, NE Minneapolis, MN
Approval Date: March 14, 2011
Approval Letter: http://www.accessdata.fda.gov/ cdrh_docs/pdf8/p080025a.pdf
What is it? The InterStim® Therapy System is a surgically implanted device used to help a patient reduce the number of bowel accidents (fecal incontinence). The InterStim® Therapy System has several components: a neurostimulator which delivers an electrical pulse to the sacral nerve; an electrical lead that is implanted on a sacral nerve, and a programmer that is used to control the electrical pulse delivered by the neurostimulator. The neurostimulator and the lead are permanent implants. The programmer is a handheld device that is not implanted. This device is identical to a device already approved for the treatment of urinary incontinence.
How does it work? The InterStim® Therapy System applies a small electrical stimulation to the sacral nerve that controls the anal sphincter. In order to see if the device will work, a patient first undergoes test stimulation. The lead is implanted on the sacral nerve and an external test stimulator (that is not implanted) is used to deliver the electrical pulse.
Patients who may benefit from long-term implantation are first identified by a two-week trial period. The patient records the number of bowel accidents they have. If their bowel accidents decline by at least half the number in a week, the patient may benefit from the treatment. The patient is then eligible to undergo surgical implantation of the neurostimulation system for long- term therapy.
When is it used? The InterStim® Therapy System is used to treat chronic fecal incontinence in patients who have failed or could not tolerate more conservative treatments.
What will it accomplish? Treatment with the InterStim® Therapy System can reduce the number of bowel accidents that a patient experiences, and in some cases, the patient becomes totally continent (does not have any more bowel accidents). In the clinical study, before patients had the InterStim® Therapy System, they had an average of nine (9) bowel accidents a week. After having the InterStim® Therapy System for 12 months, 88 out of 120 patients cut in half their number of bowel accidents, and 43 out of 120 patients achieved full continence of bowel movements. Although many patients improved, there were some patients (22 out of 120) that did not improve, or their bowel accidents became worse.
In the clinical study, 14 out of 120 patients had the device removed. In addition, 22 patients needed another surgery to fix or replace the device. Other problems seen in the study included infection and pain at the site where the neurostimulator was implanted, "pins and needles" feeling, and the neurostimulator breaking through the skin.
As the battery strength depletes over time, eventually the battery will become too weak to power the neurostimulator. When this happens, the neurostimulator will need to be surgically replaced. How long the battery lasts depends on the stimulation settings and how often the neurostimulator is on. Like any battery-powered device, the more it is used and the higher the settings, the faster the battery power will be depleted.
When should it not be used? The InterStim® Therapy System should not be used in patients who have not shown an appropriate response to test stimulation, or patients who are unable to operate the neurostimulator. In addition, patients who have had any of the system components implanted should never undergo any type of diathermy (heat treatment used for conditions such as sore or stiff muscles).
Additional information : Summary of Safety and Effectiveness and labeling are available online.