I believe you are speaking of the Autonomic Technologies Inc (ATI) Sphenopalantine Ganglion (SPG) neurostimulator device, correct? I pretty much give myself away to the very few who may know this but I have this electrode and set of 6 SPG neurostimulators surgically implanted. I paid and fought to have this procedure done in Hamburg, Germany in August of last year as a 15 year CH sufferer (last 3 years of which "chronic" and pretty much end of the line). Prior to the start of US trials at Ohio State, I am pretty sure I am the only American citizen, if there is another please speak up!, with the implant. Such a long journey but cutting edge technology and a fairly non-invasive procedure for those who find themselves even considering a surgical option when compared to Occipital Nerve Stimulators or Deep Brain Stimulation. Unlike the horrific messy stimulator procedures FDA approved in the US for treating CH this device has 1 lead wire where migration is near impossible, no battery (power generated by external radio frequency remote when held gently over upper left cheek and couples with electrode under skin) so ideally no continual surgery to replace and store battery in new part of body, and actually targets the set of nerves and fibers that are much more universally recognized as the origin of the unspeakable pain in CH attacks. I am a bio-chemist by trade, and no question the SPG, Maxillary, and surrounding offshoots of the Trigeminal are the nerves that need high frequency stimulation. 1 hour general anesthetic procedure with simple incision in the upper gum. Clinically proven MRI safe. No external scars and although non-invasive for a neurostimulator, surgery still is surgery and risks are present. However, my expected CH attacks have decreased by an astounding 90% in the last 8 months.