i have had a history of perianal crohn's including many rectal abscesses and fistulas(read my signature) so maybe I can answer some of your questions based on my experience.
1. Has anyone ever had one type of Crohns (stricturing) for several years that turned into another type (fistulizing)? I have only had rectal problems so I can't really answer this quest. From what I have read on these boards, this has happened to people as the disease progressed for some but everyone's case is so different.
2. Has anyone had a fistula that was able to be treated without requiring surgery? I have had constant surgeries including 4 different seton drains and a failed fistula plug. I was on remicade for 7 months and in that time, I got a new fistula and the 1st fistula did not close. I now have a drain through both and will probably be getting another plug in March.
3. Have you still been able to have vaginal deliveries of babies? My OB/GYN said no as did my surgeons and gastros but my disease is all rectal and the trauma that birth would cause to the area is not a risk they want me to take. Getting pregnant is another story. I have tried for 7 months and no luck. My Gastro said it was because of the constant infection but I am almost 37 so that may be why.
4. Has anyone ever had one and not developed them again?-everything I read says that they are not easily treatable and once you get them they are reoccuring. UGH!!! I have had several but again, my diease is all rectal. Remicade may be an option for you instead of surgery.
You should definitely ask your Dr. these questions. He/she may be able to give you some hopeful info.
I am currently seeing a surgeon at Mt. Sinai in NYC. I am very please with what she has done for me so far. I have 2 drains right now and in another 4-6 weeks, we will try the fistula plug surgery again. This time I am on remicade so she feels this will help. She will also do the rectal flap procedure( I stilll am not too sure I know what this is yet) but she feels the fact that is was not done by my former surgeon was the reason my last plug failed along with the fact that only 1/2 of the fistula was plugged. Keep in mind that fistulas are very complex and there is so much that Drs. still do NOT know about them (even the best surgeons in the world). I have also learned from my colorectal surgeon that amny people who do not have IBD get fistulas. Who knew?!
Best of luck to you!