Can a patient’s foot help their OAB symptoms?

A recent study evaluated electrical stimulation of the afferent nerves in the foot as a way of decreasing symptoms of overactive bladder.

Montreal-Electrical stimulation of the foot decreases symptoms of overactive bladder (OAB), according to data presented at the International Continence Society annual meeting in Montreal.

"What has been done for years is ankle stimulation," said first author Christopher J. Chermansky, MD, of the Magee-Womens Hospital of the University of Pittsburgh Medical Center, in an interview with Urology Times. "We believe if you try to apply stimulation to the sole of the foot, you can maximize the afferent stimulation there. With Urgent PC (percutaneous tibial nerve stimulation), a needle is placed through the skin and into the tibial nerve."

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A big difference between the two types of therapy is that ankle stimulation requires weekly visits to the clinician's office, whereas foot stimulation can be done at home, according to Dr. Chermansky.

"If we can provide treatment that does not have to be tied to a physician's office, then patients can be at home to do their own stimulation treatment," said Dr. Chermansky, noting another advantage of foot stimulation is that it's inexpensive. "It is convenient for patients to do this type of treatment because they can do it in their home. It can be hard for patients to return every week for 12 weeks for PTNS if they live a distance from the (physician's) office."

Next: Study builds on prior research

Dr. Chermansky previously published preliminary data on the use of electrical stimulation of somatic afferent nerves in the foot to determine whether it would increase bladder capacity and delay bladder filling sensations. The foot stimulation applied to healthy subjects who did not have OAB was found to increase bladder capacity by an average of 200 cc (J Urol 2014; 191:1009-13).

A total of 19 women with urinary urge incontinence participated in the current study, which was funded by the Colter Foundation of the University of Pittsburgh and the Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction Foundation.

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These subjects first underwent a 2-week washout of any pharmacotherapy to treat OAB. Then, they completed a 3-week voiding diary where foot stimulation was applied during the second week.

Study subjects underwent foot stimulation with a transcutaneous electrical nerve stimulator for 3 hours each evening for 7 days, with electrodes being placed on the plantar surface to activate lateral and medial plantar nerves. The pulse frequency was 5 Hz, and the pulse width was 0.2 ms. The stimulation was designed to cause twitching of the great toe, and patients could adjust the stimulation intensity to ensure patient comfort, said Dr. Chermansky.

The investigators found 16 of 19 patients responded to foot stimulation. They observed a decrease in urge urinary incontinence frequency from 3.7 leaks per day to 2.8 (p=.04), and urgency frequency fell from 7.6 episodes daily to 6.6 episodes daily (p=.03). The effects of foot stimulation persisted 4 days after treatment cessation, noted Dr. Chermansky.

Next: Results comparable to use of pharmacotherapy

All study subjects tolerated the therapy, with no patients reporting pain, redness, rash, or foot cramp or skin irritation, said Dr. Chermansky. The results are comparable to the use of pharmacotherapy to treat OAB, added Dr. Chermansky.

Dr. Chermansky acknowledged the study sample was small, and he stated that a future study is planned with more subjects, randomized between foot stimulation and a sham. In addition, the investigators plan to test different stimulation periods to define the ideal period of time needed to stimulate.