Sacral nerve stimulation (Interstim) is a modern, technological method to treat significant overactive bladder, with or without urge incontinence. Interstim functions as a sort of bladder “pacemaker” and involves eventually implanting a small electronic device in the buttock. Strangely, the chronic, constant stimulation by the Interstim lead helps to quiet a bladder. Also, certain patients who are normally unable to empty the bladder gain relief from Interstim. Our practice has performed over a hundred Interstim procedures, and we find it extremely life affecting in the right group of patients.
Typically, Interstim candidates are women or men who do not have a neurologic cause for their urinary problems, but who have frequency/urgency due to either straightforward overactive bladder or interstitial cystitis or who have unexplained urinary retention not caused by an obstruction. Furthermore, Interstim candidates have either failed or not tolerated standard medications.
Patients with overactive bladder complain of urinary urgency and frequency, waking at night to urinate, with or without leakage of urine. Many times, patients have to resort to using pads or even absorptive briefs to keep their clothes protected from urinary leaks. Patients in retention often have to self catheterize to empty their bladder.
We always examine patients to make sure there are no anatomic reasons to have urge incontinence, such as a prolapsed bladder in a woman or a large prostate in a man. We might perform a brief office cystoscopy to assess the internal anatomy of the urethra and bladder. Often, we also order a procedure called urodynamics, to learn about the bladder’s ability to store and empty urine.
Because the Interstim involves a costly implant placed through a minor surgery, we find it important to find out first whether such a device would be beneficial to a patient. Therefore we first perform a “percutaneous trial” of Interstim in the office under local anesthesia, in which tiny, flimsy wires are placed under the skin to stimulate the sacral nerves that supply the bladder. The patient remains awake for this procedure, in order to give us feedback about where he/she feels the stimulation, to verify the wires are in good position.
After several days, the patient returns with a voiding diary. If the patient feels marked improvement in urinary symptoms, then we discuss implanting the Interstim “pacemaker,” which is done in the surgery center or hospital, usually under sedation with local anesthesia. Post op instructions require the patient to avoid strenuous activity and baths/pools for approximately 3 weeks. The pacemaker can last up to 5 years without having to be exchanged.