Sacral nerve stimulation enables patients with intractable urinary retention to empty bladders more normally

A study published in the January 2001 issue of the Journal of Urology reports that continuous stimulation of specific nerves in the lower back significantly improves the ability of many patients suffering from intractable urinary retention to empty their bladders more normally.

The researchers in the study used InterStim Therapy for Urinary Control, a clinically proven treatment option for patients with nonobstructive urinary retention, urge incontinence and urgency-frequency syndrome who do not find adequate relief from their symptoms with standard medication and other forms of conservative care. Developed by Medtronic, Inc., in collaboration with leading urologists and urogynecologists worldwide, InterStim Therapy delivers mild impulses to the sacral nerves with an implantable medical device akin to a cardiac pacemaker. The sacral nerves, located in the lower back, influence bladder function.

Medtronic estimates that 20 million Americans suffer from bladder control problems, and many are women between the ages of 30 and 59 -- the prime of adult life. Urinary retention, an inability to empty the bladder completely or at all, afflicts about 1.7 million people in the United States, according to the company, and can lead to secondary health risks, including urinary tract damage and infection, overflow incontinence and reflux. Urinary urge incontinence, a chronic condition characterized by the sudden and strong urge to urinate followed by the involuntary loss of urine, and urgency-frequency syndrome, which repeatedly triggers an urgent need to urinate, affect an estimated 17 million Americans.

For tens of thousands of patients who suffer from bladder control problems, primary treatments such as medication, biofeedback and pelvic floor exercises fail to relieve their symptoms adequately. Before the introduction of InterStim Therapy in the late 1990s, these patients' remaining options were limited mainly to irreversible bladder surgery or a lifetime of absorbent pads or self-catheterization. Since then, more than 3,500 people worldwide have received InterStim Therapy.

"People with urinary control problems often struggle with simple everyday activities, such as working, shopping, traveling in a car, or seeing a movie, for fear of embarrassing wetting episodes or not being near a restroom," according to Professor Udo Jonas, a urologist at Medical University Hospital in Hannover, Germany, and the lead author of the retention study. "Sacral nerve stimulation with InterStim Therapy can improve the quality of life for most of these patients by enabling them to control their condition and focus more on enjoying life."

Clinical researchers at 13 medical centers in North America and Europe conducted the prospective, randomized study of patients with urinary voiding dysfunction, including 177 with chronic, nonobstructive retention -- 131 (74 percent) women and 46 (26 percent) men between the ages of 17 and 81 years old with symptoms for an average of seven years prior to enrolling. On average, patients who participated in the multicenter study were catheterizing upwards of five times a day, and nearly all of them had received some sort of prior treatment for their condition:

• 153 patients (86 percent) had taken medication
  
• 62 patients (35 percent) had tried a total of 271 nonsurgical interventions
  
• 83 patients (47 percent) had undergone a total of 239 surgical procedures

Based on the results of test stimulation, 68 patients qualified for implantation; 37 patients were randomized to the implant group and 31 to the control group. The implant group received InterStim Therapy immediately, while the control group received only standard medical treatment for the first six months of the study.

Compared to the control group, patients who received InterStim Therapy at the beginning of the study were able to pass significantly more urine. Overall, 83 percent of the group that was implanted first experienced successful outcomes after six months, compared to only 9 percent of the control group. The study defined success as a reduction in residual urine volume of at least 50 percent or the elimination of the need for catheterization.

The study also found that the effectiveness of InterStim Therapy as a treatment for refractory urinary retention remains constant over time. Of the 24 patients for whom long-term data was available, 14 no longer needed catheterization at their 18-month follow-up visit.
The study included no reports of serious adverse events related to the device or permanent injury associated with the devices or use of sacral nerve stimulation. The most commonly reported adverse events included pain at the neurostimulator site (15.3 percent), new pain (9.0 percent) and lead migration (8.4 percent).

Previously published research in the Journal of Urology affirmed the effectiveness of InterStim Therapy for the treatment of patients with refractory urinary urge incontinence and urgency-frequency syndrome, two other common bladder control problems.

Source: Medtronic, Inc.