Hi Ijl,
Welcome! I've done the Cipro/Flagyl rounds for fistula/abscess, eventually having surgery. For me the cipro/flagyl seemed to help the abscess from getting too large (may work better for others.) Eventually mine ruputered internally and landed me in the ER. Soon after I had a abscess/fistulectomy. The surgeon did a layopen (i believe)and cut it out without damaging the muscles. It was a painful recovery though. I take Apriso daily, along with a host of other meds. This forum contains a plethora of info on fistulas and rx's. My fistula tract seems to be coming back, however, not 100% certain yet. (keeping fingers crossed..)
PS.. Sulfasalzine was hard on my body. So was levaquin.
I hope things look up for you!
~Mon~