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.