I healed both my massive rectal fistulas by going on the SCD diet. My CD went into complete remission and I have not had a symptom or fistula since 2007. I still follow the SCD diet to this day (but not as fanatical as before), and the only drug I have ever taken was pentassa, which I still take. I refused remicade at the time of my diagnosis.
The SCD is not an over night fix, it take 5 or 6 months of 100% fanatical dedication to the diet for it too work. I started to see changes in my fistulas after 3 months and by 5 months both fistulas were so healed up, the setons had to be removed so they would heal completely.
I suggest reading the book "breaking the vicious cycle" You have to loose by trying the diet and all to gain if it works for you.