The main difference between the InterStim trial and the surgical implant is that an external device is used during the trial period, states Springfield Urology. If a patient responds well to the trial, an internal implant is used for long-term control of bowel or bladder problems.
InterStim therapy is used to treat constipation, fecal incontinence, overactive bladder and urinary retention, according to Medtronic. A trial of InterStim allows a patient to test the treatment without committing to a surgical implant. During the trial period, a doctor inserts a wire under the skin of the lower back. The wire is connected to an external stimulator that sends electrical impulses to the nerves in the sacrum. These electrical impulses help the patient achieve better bowel or bladder function.
If the patient decides to continue InterStim therapy, an internal device is implanted in the lower back, notes Springfield Urology. The internal device is programmable to give patients more control over their treatment. The potential risks of InterStim include skin irritation, pain at the implant site, unwanted changes in bowel or bladder function, numbness at the implant site, and technical difficulties, reports Medtronic. InterStim helps people with bladder problems reduce urinary frequency and limit the number of episodes of incontinence they experience. When used in people with bowel problems, InterStim may help control fecal incontinence or prevent abdominal pain.