I was also referred to Dr. Hirsch in 2009 by my ENT, after the MRI showing my AN. I had a consultation with him several months later. He has a fine reputation. He went over all of the different types of treatment with me. Surgery, Gamma Knife, Cyber Knife , fractionated and risks and side effects of each procedure. he also did a more extensive hearing test to see if hearing preservation was worthwhile. ( it wasn't). He also suggested a consultation with Dr. Paul Gardner who worked with him during AN surgery at that time. After consultations with both doctors I was impressed and actually had surgery scheduled with them at one point. I also continued researching the Gamma Knife option at UPMC, as that is very highly rated. In the end, I went with Gamma Knife at UPMC with Dr. Kondziolka.
Are you near the Pitt. area? How big is your AN?