I'm no expert on these matters, but I thought about your question. It seems to me if your dermoid cyst was very large that it COULD have been putting pressure on other organs.
That could have caused your difficulty in having regular bowel movements. By removing it, perhaps they relieved one of the problems so that you are more regular. Just a guess, but it sounds logical. I hope you do well and do enjoy regularity. I would love for my problems with it to be resolved. :(
Teresa
I had terrible problems after my last 2 surgeries, but it straightened out. Hope you feel better soon. Don't overdo, follow dr. orders. Best wishes.