Why isn't pouch surgery in ulcerative colitis not suitable for some people?

Depends : After colon is removed , has to wear a stomal bag on abdomen , need frequent change of bags few times a day, by creating a pouch , stool will be evacuated once a day or so. This needs special skills & ability , elderly , handicapped , mental illness and people with neurological problems will not be able evacuate the pouch, so they are not suitable for creation of the pouch.

What type of pouch: Are you asking about? J-pouch for the replacement of the rectum results in 6-10 bowel movements a day. Not appropriate for crohn's disease, elderly, damaged anal sphincter, etc. Other pouch is koch pouch replacement at an ileostomy site. Requires significant care and daily insertion of a catheter. Both require specially trained surgeons.