Anorectal stimulation causes increased colonic motor activity in subjects with spinal cord injury.
BACKGROUND
Difficulty with evacuation (DWE) is a major problem after spinal cord injury (SCI). Stimulation of the anal canal and lower rectum, accomplished using a gloved finger (so-called digital rectal stimulation or DRS) is often used as an adjunct to laxatives and enemas to facilitate bowel evacuation. However, the basis for the efficacy of DRS is not known. This study assessed the effect of DRS on colonic motility.


METHODS
Six subjects with SCI were studied several hours after a bowel care session. Colonic motility was assessed using a manometric catheter (affixed endoscopically to the splenic flexure) at baseline, during DRS, and after DRS. In addition, evacuation of barium oatmeal paste (with the consistency of stool and introduced into the rectum and descending colon) was assessed simultaneously using fluoroscopic techniques.


RESULTS
The mean number (+/- SEM) of peristaltic waves per minute increased from 0 at baseline to 1.9 (+/- 0.5/min) during DRS and 1.5 (+/- 0.3/min) during the period immediately after cessation of DRS (P < 0.05). The mean amplitude (+/- SEM) of the peristaltic contractions was 43.4 (+/- 2.2) mmHg. The frequency of contractions, as well as amplitude of contractions, during or immediately after DRS was not significantly different. These manometric changes in response to DRS were accompanied by expulsion of barium oatmeal paste in every subject by the fifth DRS.


CONCLUSIONS
DRS causes left-sided colonic activity in subjects with SCI. At least in part, an anorectal colonic reflex that results in enhanced contractions of the descending colon and rectum may contribute to bowel evacuation in individuals with SCI.
Korsten
Mark A
MA
Department of Veterans Affairs, Rehabilitation Research and Development Service, Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468, USA. mark.korsten@med.va.gov
Singal
Ashwani K
AK
Monga
Amit
A
Chaparala
Geeta
G
Khan
Amir M
AM
Palmon
Ron
R
Mendoza
John Reagan D
JR
Lirio
Juan P
JP
Rosman
Alan S
AS
Spungen
Ann
A
Bauman
William A
WA
D000328:Adult; D001003:Anal Canal / Q000503:physiopathology*; D044683:Colon, Descending / Q000503:physiopathology*; D020685:Colonoscopes; D003672:Defecation / Q000502:physiology; D005471:Fluoroscopy; D005769:Gastrointestinal Motility / Q000502:physiology*; D006801:Humans; D008297:Male; D008365:Manometry / Q000295:instrumentation; D008875:Middle Aged; D010264:Paraplegia / Q000503:physiopathology; D010528:Peristalsis / Q000502:physiology; D010812:Physical Stimulation; D011782:Quadriplegia / Q000503:physiopathology; D012007:Rectum / Q000503:physiopathology*; D012018:Reflex / Q000502:physiology; D013119:Spinal Cord Injuries / Q000503:physiopathology*