Hi and welcome to the Chiari forum.
I am well aware of what you are talking about, I had the decompression with dura plasty in '09.
May I ask have you ruled out ALL related condition's?
Typically they shave down a little of C1 and C2 to make room, I have not heard of a complete removal of any of the vertebras.
Have you found a true Chiari specialist?
Best of luck in your upcoming surgery. I had a duraplasty of c1 and C2. I think this is what they were referring to. Mine was a severe case, with a 3-4 cm herniation. I went to a preeminent surgeon at the time, back when extremely little was known about the malformation. The surgery itself takes a while to recover from, but it is an instant relief of severe symptoms for most.
For me it was life changing. It was done on pretty much an emergency basis ( diagnosed on a Wednesday, surgery was 5 days later) as it had actually grown into the c2 vertebrae, to the point of actually causing a pressure fracture.
I know it’s tough to face a first surgery, and a good surgeon will take the time to explain everything. Good luck.