Functional constipation refractory to medical management: The colon is the problem

Medically refractory constipation massively impacts children's health-related quality of life (HRQOL), causing chronic intense pain, severe bloating, and social withdrawal.

Historical surgical options for refractory constipation included major colonic resection and ostomy creation, sometimes permanent, without a standard protocol.

The protocol assumes the root problem in medically refractory constipation lies in the colon's physical motility function.

Contrast enema defines the degree of rectosigmoid dilation, colonic redundancy, and overall stool burden but does not predict the exact laxative dose needed.

Anorectal manometry (ARM) measures resting sphincter pressure, defecation dynamics, and the recto-anal inhibitory reflex (RAIR).

An absent recto-anal inhibitory reflex (RAIR) on ARM strongly indicates Hirschsprung disease and requires stopping the functional constipation workup.

Hirschsprung disease is a structural congenital problem where nerve cells are missing from bowel wall segments; treating it as functional constipation leads to serious complications.

ARM can detect pelvic floor dysynergia (muscles don't relax or tighten during defecation) and anal sphincter achalasia, which may require biofeedback therapy or botulinum toxin injection.

Colonic manometry (CMN) is the preferred method in this protocol for assessing colonic motility because it directly measures contractile activity segment by segment, explaining why transit is slow.

CMN measures pressure waves after fasting, after a meal stimulus, and after stimulant laxative (bisacodyl) administration.

High-amplitude propagated contractions (HAPCs) are strong coordinated muscle waves that sweep down long colonic segments and are the key drivers of effective fecal propulsion leading to bowel movements.

Group 1 dysmotility (59% of study cohort) showed slow overall motility but HAPCs were still present throughout the colon.

Group 2 dysmotility (23% of cohort) had segmental dysmotility where HAPCs started normally but stopped propagating forward, usually in the sigmoid colon.

Group 3 dysmotility (18% of cohort) was classified as diffusely inert colon, showing no HAPCs anywhere even after meal and stimulant laxative.

The Malone appendicostomy (ACE procedure) is performed laparoscopically using the appendix to create a small continent channel, usually hidden in the belly button, providing access to the beginning of the large intestine for antegrade continence enemas.

Antegrade enemas flow with normal direction from the top of the colon downward, unlike retrograde rectal enemas that push fluid upward against gravity and impacted stool.

ACE flushes are typically performed daily or every other day.

If initial ARM showed high sphincter resting pressures or pelvic dysynergia, botulinum toxin injection into the anal sphincter was performed during ACE surgery to help it relax and prevent flush retention.

The study cohort started with 196 children referred for refractory constipation; using the rigorous protocol, 22 patients were identified as having colonic motility disorder as the underlying cause.

19 out of 22 patients (86%) responded well to antegrade flushes via ACE.

Of the 19 successful cases, 17 reported zero soiling accidents with the flushes, and 2 reported only occasional minor accidents.

Even a colon that doesn't contract well on its own can function adequately if emptied regularly and effectively from above via antegrade flushes.

Three patients (14%) failed antegrade flush treatment and required colon resection within approximately 6 months after ACE procedure.

Of the 3 ACE failures, 2 were from the segmental dysmotility group and 1 from the slow motility with HAPCs present group; none were from the diffusely inert colon group.

If a child reflexively tightens pelvic floor muscles when large flush volumes come down, they might retain fluid, leading to pain, leakage, and treatment failure.