I have a dural fistula, which I understand is an AVM. I've had surgery twice but it keeps coming back

Let me explain that statement. In September 2009, I finally had surgery for what was originally diagnosed as a lipoma. (a fatty tumor of the scalp) I had had an MRI, for this painful, malleable area on my crown of my head, but the neurologist (not a neuro-radiologist) said there wasn't anything there. I was sent to a dermatologist for a biopsy and thank God, he missed the DF and just got my scalp or my neurosurgeon told me later I would have died on the table. The only reason he was present for the surgery (besides God having him there)was that the General Surgeon who was tasked with removing the lipoma insisted that he be there "just in case." I've read the operative notes. I don't believe that either of them knew it was a fistula at that time. But the pathology called it an angioma and the follow up notes the neurosurgeon called it a dural fistula. Four months later it was back, along with a second one on the other side of my head. Again, I wasn't told it was a dural fistula, but the notes do talk about a fistula track from one to the other. And how the first came up with the "cement" in the hole in the middle of it. Now I have what seem to be 2 maybe 3 more areas right by the ones before.
What make mine different is that these are the symptoms it seems of a deeper problem, the AVM itself? I seem to form these little tumors with arteries and veins and spinal fluid on my skull that come out of my brain.

I had thought I was free- or maybe fooled myself is more honest- but I had a TIA July 12, and it started with a horrendous headache unlike any of the other TIA's I have had. Once again, there was no bleeding, but I had a lot of weakness on my left side with my leg, some with my arm and hand. I also had some short-term memory issues and word recall issues...all of which I am getting therapy for. Thank God for that! And the therapists all assure me that these are stroke related issues, so I don't think they are related to what's happening with my head.