Josh: I live in NYC....Here is what I have been able to find/research on doctors in the city.
Dr. Peter Costantino (Head and Neck Surgeon) and his partner Dr. Sen, are highly regarded and are at Roosevelt Hospital, the Cranial Base Surgery Center.
Dr. Jeremy Sisti (who does both Radiation and Microsurgery) is at Columbia and is highly regarded.
Dr. Roland and Dr. Golfinos (both at NYU) are also highly regarded.
From my research, these people specialize in ANs and treat them extensively. There may be others, but I have not heard of their names yet. I consulted with Dr. Costantino last week, and will be seeing Dr. Sisti on Thursday.
Hope this helps.