Hi Janet, when I was first diagnosed, everybody I know was contacting every relative, friend, friend of a friend who they remembered having some kind of brain surgery. Not many turned out to have had an AN. One of the women who contacted me also had a Chiari Malformation. My understanding is that the skull is too small and the cerebellum literally starts to squeeze out of the space it would normally reside in. The pressure is caused by the cerebellum trying to fit into this small space. I checked on the definition and it said "Chiari malformation occurs when the section of the skull containing the cerebellum is too small or is deformed, thus putting pressure on and crowding the brain. The lowermost portion, or tonsils, of the cerebellum are displaced into the upper spinal canal."
I definitely agree with you that this "shoving" of the cerebellum during retrosigmoid surgery and any subsequent scarring can cause headaches. And I'm sure the trigeminal nerve being disturbed, too, doesn't help with headaches either. My neurosurgeon pretty much said so, and he asks me at every visit if I have headaches. I'm a little over 3 months post-retrosigmoid from my AN removal and right now I don't have constant headaches. I do get the stabbing, sharp trigeminal pain, and I have the normal facial aches and feelings that occur to a paralyzed face. I still don't have movement, but I'm hopeful.
