I was diagnosed with Crohn's as a result of hemmie surgery. A month after the surgery my incisions hadn't healed at all, and I ended up in a terrible flare. One thing you should know is that the traditional surgery is very painful. You don't realize it, but you use the muscles around the anus constantly. The pelvic floor stablizes you, so any movement just about anywhere in your body will jostle the incisions, and that hurts. It was a solid six weeks before I could stand to sit properly on my butt.
I will say, the one positive of this surgery was that even with the incisions, it was immediately less painful to have a bm than it had been with the hemmies. Mine were really bad, I'd had them for a year, and they weren't responding to the hydrocortisone suppositories anymore. Definitely talk to an experienced colon-rectal surgeon. I had mine done by a general surgeon, and that was a big, big mistake.