I just had this surgery, Occipital Nerve Stimulator or ONS, a week ago. I did the trial version 2 months ago and it was successful. They will actually activate and program the implant tomorrow. I suffer from severe cluster headaches and migraine headaches. I have tried nearly everything else there is for relief. There is a great facebook page forum called Occipital Nerve Stimulation. There is lots of great information available. It is still considered to be and experimental procedure but it has actually been around for a long time with incredible results. It took me 3 years of research before deciding to have this surgery. I believe that if you suffer from chronic pain and nothing else has helped this is a great option. It is not a cure. They believe if it reduces your pain by 40% it is successful but most people i talked to had way greater results than that. If you would like more info let me know.