Sacral Neuromodulation in Dual Incontinence: Ultrasound and Afferent Nerve Sensation Assessment

One in four women reports bothersome symptoms of a pelvic floor disorder with 16% reporting urinary incontinence (UI), otherwise known as leakage. Likewise, 1 in 5 women with UI reports fecal incontinence (FI). Women with dual incontinence (UI/FI) often have more bothersome symptoms, quality of life impact, and sexual dysfunction than those with just UI or FI. In many situations, bladder and/or bowel control problems are the result of a failure of communication between the brain and the sacral nerve. The sacral nerve controls the bladder, bowel, and pelvic floor and the muscles related to their function. If the brain and sacral nerve do not communicate correctly, the bladder and/or bowel cannot function properly, which often leads to incontinence, or leakage. The only currently available treatment with level 1 effectiveness data for the treatment of BOTH UI and FI is called Sacral Neuromodulation. Sacral Neuromodulation (SNM) is a standard of care procedure used to treat men and women that have symptoms of Urinary and Fecal Incontinence and involves surgically implanting a device in to the patient's body to target this communication problem by stimulating the nerves that control bladder and bowel function with mild electrical pulses. This helps the brain and nerves to communicate so the bladder and bowel can function properly. It is known that changes in nerve stimulation and muscular function are important factors in the cause and onset of UI and FI and in how a patient will respond to various treatments, however, the precise mechanism of action of SNM on UI and FI remains unclear.

This study therefore aims to obtain a better understanding of nerve and muscle function in patients with dual incontinence and to quantify how SNM affects the nerves of patients with dual incontinence. We hope to do so by using Current Perception Threshold (CPT) Testing, which is a way to quantify the function of different populations of afferent nerves. We will recruit patients who already plan on undergoing Sacral Neuromodulation implantation for the treatment of their dual incontinence, and as part of the research study we will use CPT testing to measure the amount of stimulation required to activate the participant's sacral nerve before SNM and will also measure the current perception threshold of the participant's sacral nerve after SNM treatment. We expect to see a difference in the amount of stimulation required to activate different pelvic floor nerves before and after the device implantation. By learning more about nerve function in patients with DI, we hope to find a way to screen patients before treatment with SNM to make sure the treatment will work for them. We also hope to learn how urethral and anal sphincter anatomy in patients with dual incontinence changes after treatment with SNM. Lastly, we will study the quality of sexual relationships in women with dual incontinence and their male partners and attempt to identify specific areas of dysfunction that are common in patients with DI.