I am sorry to hear that your suffering from the A.N especially 4 years out of CK. I have heard of some people having issues after Radiation. There was a man in my support group at NYU in NYC that had to have surgery after Radiation and it was successful. I have heard the Doctors refer to some tumors as sticky. I think that is what mine is even before my Gamma Knife in 2017. I had my Gamma Knife in June 2017 for 7.5 mm AN , it swelled to 1 cm and six month later retracted back 7.5 mm. I lost some hearing, still have dizziness more on humid days and my balance is still not the greatest but still some things have improved . My tumor is just touching my facial nerve and it never completely died but it’s stable and I am not scheduled for another MRI until 2021.
Maybe Fractional Radiation would help you? I had consult with Dr Gil Lieberman in NYC and he was well informed , I believe he is the originally pioneer of that type of Radiation? If you are able to travel to NYC NYU has a great staff that’s where I had my Gamma Knife with Dr Kondziolka, I think he is one of best Doctors I have met that specializes in AN’s and if I need surgery which I think that I might down the road because of ear ,facial pain and headaches than I am going with him. I wish you the best of luck with your AN. I hope that you find the help that you need!