I have colonic inertia, a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally, due to MS. I was dx'd 5 years ago. I had a major flare and was numb from the waist down. I couldn't even feel myself wipe myself (sorry for the TMI). So I think that was the start of the damage and it's just gotten worse to the point where the colon won't function at all. I can't go to the bathroom without a laxative.
I suspect I might also have pelvic floor dysfunction which is critical for proper bowel movement.
That is why I think that I am going to end up having to have the colon removed.