The bladder is the organ that stores urine. As the bladder fills, nerve signals cause the muscles in the bladder wall to contract. This forces urine from the bladder, into the urethra. The muscles that surround the urethra also relax, allowing the urine to flow out of the body. In overactive bladder, the nerves misfire, signaling the bladder muscles to contract even if the bladder only contains a small amount of urine. Patients experience a sudden, uncontrolled release of urine.

Overactive bladder is characterized by four main symptoms:

Urinary frequency - a need to urinate eight or more times a day or two or more times during the night.

Urgency - a sudden, uncontrolled sensation of the need to empty the bladder.

Incontinence - leakage of urine (the volume can be a very small, from a few drops, to a large amount of wetting).

Nightime urgency - awakening at night with the need to urinate.

According to the National Association for Continence, overactive bladder affects about 33 million American adults. Risk increases with age. By 40, about 20 percent of men and women have some degree of symptoms.

Treating Overactive Bladder

Many patients choose to live with their overactive bladder symptoms by using incontinence pads and trying to remain close to a restroom. However, there are treatments. Medications can be used to relax the bladder and prevent unexpected muscle contractions. Some behavioral therapies may also be helpful (like biofeedback and Kegel exercises).

Another treatment involves electrical stimulation of the nerves that control bladder function. A small electrical stimulator is implanted under the skin in the pelvic area. The device emits a mild electrical current to stimulate the nerves and prevent uncontrolled release of urine from the bladder.

Percutaneous Tibial Nerve Stimulation (PTNS)

Another treatment for overactive bladder is percutaneous tibial nerve stimulation, or PTNS. The treatment is delivered in a physician's office through a device called the Urgent® PC Neuromodulation system. A fine needle is inserted into the skin just above the ankles, near the tibial nerve. When the system is turned on, a mild electrical impulse passes through the needle into the skin. The signal travels along the tibial nerve until it reaches a group of nerves near the base of the spine, called the sacral nerve plexus. The stimulation helps to improve bladder function. The treatment is typically given once a week for 30 minutes at a time over 12 weeks.

According to the manufacturer, 2/3 of people treated with the Urgent PC system have a reduction in symptoms. Bruce Kahn, M.D., F.A.C.O.G., an Obstetrician-Gynecologist at Scripps Clinic Carmel Valley, says about 50 percent of patients see results after 4 to 6 treatments. Another 30 percent have improved symptoms within 8 to 10 treatments.

PTNS provides relief from bladder symptoms without the need for implantation of an electrical stimulator under the skin. Kahn says patients usually require maintenance treatments, but the timing and number of extra treatments is still not known. PTNS can be used to treat other incontinence problems, like urge incontinence, interstitial cystitis and, in men, incontinence after radical prostatectomy. The treatment won't help symptoms of stress incontinence. It is also not recommended for those with pacemakers or implantable defibrillators, patients who are prone to bleeding, people who have nerve damage or women who are pregnant or plan to become pregnant during the treatment time.

For information about the Urgent® PC Neuromodulation System or to locate a physician, log onto to company's website at http://www.uroplasty.com.

For general information on overactive bladder or other forms of urinary incontinence:

American Urological Association

National Association for Continence

National Institute of Diabetes and Digestive and Kidney Diseases

The Simon Foundation for Continence