I had this surgery (fistulotomy) a few years back. Basically I had a gapping hole down there, they laid open the fistula track, and let it heal from the inside out. I was in moderate pain for probably 3-4 days. Going to the bathroom hurt the worst, obviously. I also took stool softeners, but would find myself crying when going to the bathroom! After that I was good, driving, and moving around without pain. I had to soak it several times a day, which wasn't fun.
The only bad thing for me, was that it took a WHOLE year to heal up. Which I've read is common in Crohn's patients.
Diagnosed with mild Crohn's Disease 2/06 after sever GI bleed. Has been suffering since 1998. History of rectal fistula and gallbladder removal. Currently taking Asacol and Questran.