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

DEVICE

Genital Nerve Stimulation

Electrical stimulation applied to the genital nerve with surface electrodes using an off the shelf TENS unit (Ultima Plus). First, an amplitude threshold for the pudendo-anal reflex responses will be determined. Then, sham (1-2 Hz) and effective stimulation (20 Hz) will be briefly applied to record responses. Then, stimulation will be applied in random presentation order to record any changes in anorectal manometry outcomes due to both sham and effective stimulation.

DIAGNOSTIC_TEST

Clinical exam

Examination by physician determines the presence of pelvic reflexes (pudendo-anal and bulbocavernosus) which are essential for GNS to have an effect.

DIAGNOSTIC_TEST

Collection of SCI common data elements

Data regarding participant demographics, history of injury, and medical history will be collected.

DIAGNOSTIC_TEST

Bowel function survey completion

Two surveys will be conducted to assess the bowel function of the participant. The International SCI Bowel Function Basic Data Set (ISCI BF BDS v2.1) and the SCI Qulaity of Life Bowel Management Difficulties (SCI-QoL BMD) survey scales collect data on overall bowel function and how any difficulties impact the participants quality of life.

DIAGNOSTIC_TEST

International Standard for Neurological Classification of SCI (ISNCSCI)

The physician will conduct the ISNCSCI to determine the level and severity of injury to the spinal cord. This is done by determining the ability to detect light touch and pinprick stimulation. Outcomes will be a Spinal Injury Association Impairment Scale (AIS) grade of A-D.

DIAGNOSTIC_TEST

Response to genital nerve stimulation (GNS)

GNS will be applied to determine if there is a response in the participant. If the participant has no response to the stimulation they will be excluded from the second visit as it is dependent on the ability to respond to GNS.

DIAGNOSTIC_TEST

Anorectal Manometry testing (ARM)

The participant will be instrumented for ARM testing. This requires a special balloon catheter to be inserted into the anus and secured, surface electrode pads being applied to the anal sphincter, and electrode pads being applied to the genital nerve stimulation sites. Once instrumented, the participant will be tested with the London Classification procedure. This procedure asks the participant to perform several actions (squeeze to withhold a bowel movement, push to have a bowel movement, and cough) as well as inflating the balloon on the catheter to determine reflex thresholds (RAIR, retroanal inhibitory reflex which relaxes the anal sphincter in response to rectal distension) and sensory thresholds (first senstation,

ARM outcome - Rectal wall tension

Time frame: Up to three weeks after enrollment

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.

ARM outcome - Anal sphincter function

Time frame: Up to three weeks after enrollment

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.

ARM outcome - Rectoanal reflex activity (RAIR)

Time frame: Up to three weeks after enrollment

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.

ARM outcome - Rectal sensation

Time frame: Up to three weeks after enrollment

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.

ARM outcome - Presence of hyper reflexive rectal contractions

Time frame: Up to three weeks after enrollment

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.

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.