I would highly recommend Dr. Leland Albright - he is absolutely one of the best in his field. He is a pediatric neurosurgeon, but treats adults with Chiari and Syrinx. Maroon is a good option as well.

I would be cautious about Bejjani. My sources tell me that he is very "quick to cut" - operates on anyone for any reason. He books so many cases in one day that he has to rush through them. I had a friend who was supposed to have a spine fusion with Bejjani - took him into surgery at 6 pm, ran out of time, and only did the laminectomy, not the fusion. The fusion had to be done by another surgeon - my friend would not go back!