Peripheral Nerve Stimulation for Urge Incontinence

DESCRIPTION (provided by applicant): Urinary incontinence is a significant medical problem affecting over 13 million Americans that is not adequately addressed by current treatment options. Electrical stimulation to treat incontinence has been tested and proven effective in both animal models and humans. Currently, one product using electrical stimulation applied to the sacral nerve roots to treat urge incontinence (interstim(r), Sacral Nerve Stimulation (SNS) TM System, Medtronic Corp., Minneapolis, MN) is commercially available. The long-term goal of this project is to develop and commercialize a superior alternative neurostimulation product. The specific aim of this Phase I proposal is to demonstrate that electrical stimulation of the dorsal genital afferent nerves acutely inhibits bladder contraction and reduces the acute symptoms of urge incontinence in patients who were unsuccessful with the Medtronic Interstim System. The Interstim SNS System is indicated for the treatment of urinary urge incontinence in patients who have failed or could not tolerate more conservative treatments (e.g. pads, catheters, medications, behavioral therapy, surgery). However, only 63% [Schmidt] of potential candidates screened through an invasive test procedure were eligible to receive the implanted device, and 75% of those implanted achieved a 50% or greater reduction in incontinence episodes. Thus, the 53% of patients who are not successful with the Interstim product have no desirable remaining options. Further, in a multi-center clinical trial of 157 implanted patients, 32.5% of patients required surgical revision. We hypothesize that patients are unsuccessful with the Interstim device because of the location of the sacral nerve electrode. The Interstim electrode is placed in contact with one of the sacral nerves as it passes through a bony canal in the spine. In this location, stimulation is applied to the whole S 3 sacral nerve, and in some cases successfully activates the sensory fibers that inhibit bladder contraction. The approach we propose will stimulate specifically and directly a purely sensory nerve that has a consistent inhibitory effect on reflex bladder contraction. Our proposed approach to electrical stimulation for control of urge incontinence is expected to have a non-invasive screening procedure, a simpler implant procedure, and greater efficacy than the competing product for a broader patient population. At the conclusion of this Phase I project we will have determined the feasibility of treating urge incontinence by electrical stimulation of the dorsal genital nerves and gain insight into why these patients were not successful with the Interstim device. If successful, this development will result in a new treatment option for persons with severe urge incontinence.