MINNEAPOLIS, MN -- Aug. 25, 1999 -- A study appearing in this month's issue of The Journal of Urology indicates that sacral nerve stimulation is an effective treatment alternative for those who suffer from urinary urge incontinence and have not responded favourably to more traditional therapy options, such as pelvic muscle exercises and medications.
More than 13 million American men and women suffer from urinary control problems, with an estimated one million new cases diagnosed each year. Approximately 85 percent of those who suffer are women between the ages of 30 and 59 -- women in the most active, productive years of their lives. For these women, the effects of incontinence are especially debilitating.
Those with urinary urge incontinence may feel a strong urge to urinate and are often embarrassed by leaking episodes. Although a variety of drug therapies are available to them, some people do not respond well to medication and are often resigned to managing their condition with absorbent diapers or pads or major surgery.
The article highlights results from a prospective, randomised study, held at 23 world-wide centres. The purpose of the study was to examine the effectiveness of sacral nerve stimulation in treating urinary urge incontinence. All candidates underwent baseline screening to determine their eligibility for the study, and almost all had undergone previous medical treatment that had failed in alleviating their condition.
Out of a pool of 155 urge incontinence patients, 98 were pre-screened as viable candidates for the study. The 98 patients were then randomised into two groups, where 52 patients were scheduled for implant of the system and 46 patients were followed as a control group.
Control patients underwent standard medical therapy for six months and thereafter could cross over to the implant group, to receive sacral nerve stimulation therapy. All patients who were enrolled agreed to keep diaries of their condition throughout the duration of the study. After six months of sacral nerve stimulation therapy, a Therapy Evaluation Test was performed, where stimulation was turned off to determine the effects of discontinued therapy.
Sacral nerve stimulation for the patients was provided via Medtronic InterStim Therapy for Urinary Control. InterStim Therapy uses neurostimulation to send mild electrical pulses to the sacral nerves in the lower back that influences bladder function. A neurostimulator, about the size of a stopwatch, is placed under the skin of the abdomen and generates pulses that are carried via a thin implanted lead, or wire, to the sacral nerves. Physicians can non-invasively adjust the strength of stimulation to a level that helps each patient the most.
After six months of treatment, the number of daily incontinence episodes, the severity of episodes and the frequency of absorbent pads or diapers replacement due to incontinence were significantly reduced in the implant group when compared with the control group.
In the implant group, 47 percent were completely dry at six months and these results were sustained at 12 months after receiving the therapy. Furthermore, an additional 28 percent of the implant group had a 50 percent or greater reduction in the number of leaking episodes they experienced. Control group patients demonstrated no clinical improvement at six months.
Additionally, when stimulation was deactivated during the therapy evaluation test six months after implantation, voiding diaries indicated a return towards baseline urge incontinence, with no adverse effect on baseline voiding function. This illustrated the reversible nature of the therapy and demonstrated that the therapeutic results were attributed to the application of the therapy.
About a third of the patients who received devices underwent subsequent surgery to reposition or replace elements of their systems. The adjustments were intended to resolve device or therapy-related adverse side effects. The most commonly-reported adverse events included pain at the implant site (19.1 percent), pain at the neurostimulator site (15.9 percent) and lead migration (seven percent). The surgical revisions did not preclude a favourable clinical outcome for the patient. No adverse events resulted in permanent injury, however nine percent remained unresolved at the time of database closure.
"As illustrated by the study results, the difference that sacral nerve stimulation can make in the lives of these patients is quite dramatic," said Steven Siegel, M.D., of Metropolitan Urologic Specialists in St. Paul, MN. and one of the co-authors of the study. "In properly-screened candidates, sacral nerve stimulation can mean the difference for these patients between a near-normal daily existence and a life-limiting existence, where they suffer through the physical and psychological implications of their condition."
InterStim Therapy first received FDA approval in September 1997 for
the treatment of urinary urge incontinence. In April of 1999, InterStim
Therapy was also approved by the FDA for significant symptoms of urgency-frequency
and non-obstructive urinary retention.