The Interstim System was approved by the FDA in 1997 for urge incontinence and in 1999 for urinary retention and urgency-frequency. In 1994, it was FDA approved for fecal incontinence. It has been available in the United States for over a decade. While the Interstim device is not approved for the treatment of pelvic pain and interstitial cystitis, it is sometimes used for pelvic pain and interstitial cystitis with some success. InterStim therapy is a pacemaker for the bladder used to reestablish appropriate nueromodulation of the bladder and rectum. The device works by using a stimulator device in the buttocks to stimulate the S3 nerve root in the pelvis. This is the primary nerve root for bladder function. Stimulating the sacral nerve number 3 (S3) nerve root with the InterStim device can result in dramatic decrease in frequency, urgency and urge incontinence. InterStim therapy can also improve bladder emptying and result in decreasing post void residuals and therefore decreasing urinary tract infections and the other complications of incomplete bladder emptying.
Other treatments for overactive bladder include behavior modification, timed voiding, anticholinergics, pelvic floor retraining, and Botox bladder injections. Anticholinergic medications can be used to inhibit bladder smooth muscle to treat frequency, urgency, and urge incontinence. Anticholinergic medications will also inhibit smooth muscle in the ciliary muscle of the eye, the salivary gland, and the intestines. Therefore, these medications can cause problems for the patients with acute angle glaucoma and these medications can cause dry mouth and constipation. InterStim therapy does not cause changes to smooth muscle cells outside the bladder and so it does not cause problems for glaucoma patients and it does not cause dry mouth or constipation. InterStim therapy can improve the elastic properties of connective tissue in the bladder and therefore it can help many patients who do not respond to anticholinergic medications. Anticholinergic medications will have no effect on the connective tissue of the bladder wall. If a patient has significant frequency, urgency, and urge incontinence there may be changes in the bladder wall connective tissue. For these patients there may be minimal or no change with anticholinergic medications. Interstim therapy can be very effective in such cases.
For patients with significant symptoms of frequency, urgency, and urge incontinence who have tried anticholinergic medications and/or other therapies but are not getting satisfactory results or cannot tolerate these medications InterStim therapy is an excellent choice. The two-steps include a simple test stimulation in the office or surgery center to gauge whether the patient is appropriate for InterStim therapy followed by subsequent implantation of the InterStim leads and the InterStim generator in the operating room.
The first step for InterStim therapy is a simple test stimulation in the office or surgery center. Tiny wires are implanted into the small of the back near the S3 nerve and these tiny wires are connected to a generator box worn on the hip. The patient wears this box and these tiny wires over the ensuing week and tests for improvements in voiding
symptoms. The wires are easily removed in the office and the results can be reviewed to determine if the patient should proceed to the next step.
The second step in InterStim therapy is placing the InterStim leads and generator. The InterStim leads are placed in the same location as the test wires. That is, the InterStim leads are placed near the S3 nerve root in the lower part of the back with the patient lying on their abdomen. For this second step, as with the first step the patient is under IV sedation. With IV sedation the patient is sleepy but able to answer some simple questions at certain times during the procedure. Both in the first step and with the second step local anesthetic is also used to make the patient very comfortable. The InterStim lead is then connected to the generator implant. For the final generator implant the generator, which is oval shaped, 1 x 2 inches, and about a half-inch thick, is placed into the buttocks and connected to the InterStim leads. This generator can be programmed with an external magnet to set the intensity and frequency of the stimulation to a level that produces the desired results.
Like any battery-powered device, battery life depends on many factors such as program settings/amplitude, on and off cycles, lead placement, etc. At your follow up visits, your provider can check the battery life. Replacing the battery requires replacing the neurostimulator, which is done during an outpatient procedure.
For informational purposes only. Please consult your physician with any questions. USA Delaware 302-571-8958.
