I had my Gamma knife procedure on November 7th of 2013.It took about 8 months for my pain to go away completely.I still take one 200 mg pill of carbamazepine at bedtime,just to keep it in my system.At first ,after the GK,I had about 2 months with no pain,but the pain came back and I neded 400 mg of carbamazepine daily.At least this 400 mg was less than before my GK,when I was taking 800mg.So far I am now very grateful for my no pain way of life,except for a few, I guess old age body aches,which I can tolerate.The GK procedure was not difficult for me at all,oh except when they fastened the head frame on me.The discomfort was minimal.....Good Luck,stay pain free....Dave W