Electrical rectal stimulation to promote bowel emptying after spinal cord injury

Following spinal cord injury, the colon is unable to evacuate stools via peristaltic propulsion. Losing bowel
function can cause constipation, gastro-intestinal complications, and faecal incontinence, severely impacting
health and quality of life. The standard of care for individuals with neurogenic bowel involves the design of a
bowel program for predictable and effective elimination of the bowels. A bowel program includes diet, fluid
intake, activity, and pharmaceutical (suppository) or mechanical rectal stimulation. However, the bowel routine
can require over an hour or more to evacuate the bowels and this process typically requires the assistance of a
caregiver, which adds to the cost of care and reduces independence. Restoring bowel function is considered a
high priority, but remains a critically unmet need requiring further development. The objective of this project is
to determine the feasibility and potential effectiveness of minimally invasive patterned electrical stimulation on
bowel emptying in Veterans with spinal cord injury and neurogenic bowel.
We propose experiments with human study participants to develop and evaluate an approach to improve
bowel emptying. The majority of individuals with neurogenic bowel dysfunction use digital rectal stimulation to
distend the rectum and evoke an excitatory recto-colonic reflex, which increases colonic motility and loads
stool into the rectum for removal. The proposed approach would substitute digital rectal stimulation with
electrical rectal stimulation, using electrical stimulation of sensory (afferent) neurons of the rectum to modulate
the recto-colonic reflex. Preliminary data have shown that 1) the colon responds to electrical stimulation in
animals and 2) that rectal stimulation was correlated with bowel activity in two Veterans with spinal cord injury.
We hypothesize that the recto-colonic reflex can be evoked via electrical stimulation of rectal afferents and
promote clinically meaningful bowel emptying. This work will provide new insights for the development of a
sensory afferent stimulation-based neuroprosthetic device to restore bowel function following spinal cord injury.

Grant Number: 5I01RX004529-02
NIH Institute/Center: VA
Principal Investigator: DENNIS BOURBEAU