Are you 100% sure it failed? 5 months is a rather short time-frame to confirm failure. Don't they usually give it at least a full year to see if it's just swelling instead of failure?
Anyways, I feel your concern and fear. I think it goes without saying that I would get "second opinions" from several experts in the field, regardless of where the primary treatment took place.
As you know, Dr. Schwartz and Dr. Friedman are at the top of the list regarding surgery after failed radiation.
In a previous post, I listed some of the top places for treatment. I would simply mail a copy of your most recent MRI and medical history for their free consultation over the phone. This is strickly my "Top 10" personal list:
Dr. Lunsford - Gamma Knife at UPMC Pittsburgh, PA
Dr. Chang - Cyber Knife at Stanford, CA
Dr. Kondziolka - New Jersey, Manhattan, New York
Dr. Sheehan - Univ. Virginia - Gamma Knife - UVA
Dr. Schwartz - House Ear Clinic - Los Angeles, CA
Dr. Friedman - Keck Univ- California
Stephen Tatter and Michael Chan - Wake Forest University North Carolina - Gamma Knife
Clinton A. Medbery, III, M.D. Southwest Radiation Oncology - Oklahoma
Dr. ALLAN THORNTON - Proton Beam Therapy - Hampton University
MDM Cancer Center in Texas
And perhaps your local Gamma Knife, Cyber Knife, or Microsurgery specialists.
Sometimes they can "re-radiate" depending on various factors. It's been said that it's may be more difficult to perform microsurgery after failed radiation; however, Dr. Schwartz indicated an 85% positive outcome with tumors of my size/position (1.8 cm) following surgery with HIM after failed radiation.
Each case is unique and different, but I encourage you to contact him.
Whatever decision you make, I wish you well in your journey. A fully informed decision is the best one you can make.