As said many times over on the site, everyone is different...lol.
I was on Remicade for 5 years, and at first it helped with the fistulas and abcesses, but unfortunately it no longer works. So in my case, the doctor feels that doing a temporary colostomy to stop the stool from passing to the part of the colon were the fistulas are located will help to heal them.
And yes, I have had surgeries in the past where the bowel just gets so "rotten" that meds will not heal it. Surgery is usually a last-case senario for one of the symptoms, as the surgeries themselves come with many complications... scarring, strictures, etc.
There are many on here who haven't had surgery yet, so you are not alone!