Acute Genital Nerve Stimulation for Neurogenic Bowel Dysfunction in Individuals Living With Spinal Cord Injury

When an organ relaxes during filling it is called compliance and is characteristic of the rectum and bladder. This allows the organ to hold more material and therefore have a larger void when emptying. After SCI, organs that have had their control systems damaged become spastic and hyperreflexive which leads to smaller volumes and incontinence issues in both bladder and bowel function.

By inflating the ARM balloon with air we can slightly distend the rectum and measure the pressure (cmH20) to determine compliance. If the pressure stays the same after inflating the balloon then the rectum has relaxed and it is a measure of compliance. Rectal wall tension will be inferred from this response and abnormal tension will be apparent by reduced compliance (pressure increases when balloon volume increases).

This measure will be recorded with and without stimulation.

Circumferential sensors on the ARM balloon catheter will detect pressure changes (cmH20) in the anal sphincter during cough, push, squeeze, and rest. Anal sphincter function will be assessed with and without stimulation.

Air will be infused into the ARM balloon to distend the rectum. When the rectum is distended the anal sphincter relaxes (rectoanal inhibitory reflex) and the amount of air required to elicit the reflex (cc) will be assessed with and without stimulation.

Air is infused (50 ml steps) into the ARM balloon until the participant reports: first sensation, urge to defecate, maximum tolerable sensation. The volume of air (cc) is recorded for each sensory event with and without stimulation.

After SCI the rectum become hyperreflexive and spastic. A major cause of fecal incontinence after injury is the result of these reflexive contractions and the inability to contract the external sphincter to maintain continence. This combination causes the rectum to expel small amounts of stool rather than storing the material for a larger bowel movement.

We will quantify the rectal pressure traces for reflexive contractions and measure their frequency (Hz or count/minute, whichever is most appropriate). Reflexive contractions will be steep increases in rectal pressure while at rest or during distension (sensation and RAIR testing). Measurements will be collected with and without stimulation and compared.

A survey on bowel management difficulties and the effect of those complications on the participants quality of life will be conducted and data collected by study staff. Answers are chosen from a 5-point Likert scale from 1 (never/not at all) to 5 (always/very much) and higher scores represent greater difficulty managing bowel complications.

A survey on bowel function after SCI will be conducted and data collected by study staff. The instrument is on a scale from 0-45 with higher scores indicating greater dysfunction.

This is a standard assessment tool to determine level and severity of injury by the American Spinal Injury Association. The test uses pin prick and light touch to determine motor and sensory capability along the body. At the end of the test the participant will have information on their level (i.e. T8) and severity (grade A-D, with A being motor and sensory complete injury). These endpoints overlap with the clinical exam outcomes and will only be conducted once. Therefore, the ISNCSCI is being conducted in the context of the clinical exam endpoints below.

Data will be collected regarding body system categories (constitutional symptoms, eyes, ears/nose/mouth/throat, cardiovascular, respiratory, gastrointestinal, genitourinary, musculoskeletal, integumentary, neurological, psychiatric, endocrine, hematologic/lymphatic, and allergic/immunologic) including start date, end date, and ongoing status.

Data regarding the injury etiology and time frame will be collected from the participant.

Data regarding the participants' gender, birth date, race, ethnicity, marital status, number of members in household, area of residence, number of years of education, and primary occupation.

An SCI-specialized clinician will assess the participant in regard to abdominal health. This data will be incorporated into a clinical characterization of bowel dysfunction.

An SCI-specialized clinician will assess the participant in regard to the integrity of the sacral reflexes. These include the pudendo-anal reflex (PA) and bulbocavernosus (BC) reflexes that are critical for responding to the genital nerve stimulation.

An SCI-specialized clinician will assess the participant in regard to anal sphincter tone. After injury the external anal sphincter is either spastic (tightly closed and difficult to relax) or flaccid (completely lax and does not contract) based on the level of injury. If the damage to the spinal cord is at the level of the sacrum (just above the tailbone area) it will cause a flaccid phenotype and indicates damage to the reflex pathways necessary for the experiment.

An SCI-specialized clinician will assess the participant in regard to areas of the body that have sensation. This data is incorporated in the ISNCSCI test and will not be duplicated.

An SCI-specialized clinician will assess the participant in regard to the lowest area of the body that the participant is able to contract voluntarily. This data is incorporated in the ISNCSCI test and will not be duplicated.