They do have to push the brain (or use other means to draw it) back up into the skull. They don't dig into the brain, but they move it. So I guess it really depends on how you look at it. My NS told me it was brain surgery. And also that I could tell everyone it was because my brain was too big for my skull ;)
My Neurologist likes to refer to it as "neck surgery," which kind of irritates me. But I think my surgeon trumps him.
I am only assuming here, so don't take my word at it. It would be considered a brain surgery when they have to use a duraplast or some other type of patch when the doctor opens up the membrane that surrounds the brain. I also don't know if its true but according to some of the stories but some of the doctors shave the tonsils to free up the csf flow. So this would be considered brain surgery as they are opening the dura (the membrane that surrounds the brain) and if the doctor shaves the tonsils. But technically they refer to all operation the contain the skull brain surgery. Why? I have no clue, but a few years before I even found out that iI had Chiari I was contemplating having the front part of my left lobe of my brain removed that causes headaches and migraines but once I learned everything that this surgery required I decided against it. I hope this helps.
That's true... I did have the duraplasty, so maybe that's why. I don't know. I think anytime they dig into your skull and touch your brain, it's brain surgery. Or close enough for most any descriptors. It certainly isn't minor surgery.
Ok. All good points. Thanks y'all.
The brain surgery aspect does come either from the opening of the dura (brain lining) and if applicable from the stimulation procedure to get the tonsils to slightly retract back into the skull.