I am sorry ... I know this must have really floored you. If you have not yet, please do read Sammy's story.
Here is a list of the neurological things wrong with him (he also has a couple of other medical issues) .. but Sammy is a happy boy
:
1. chiari-like malformation
2. chronic atlanto-axial subluxation
3. hydrocephalus
4. syringohydromyelia
5. cervical intervertebral disc disease
6. subarachnoid cyst
It sounds like Cassie is very similar to Sammy....and let me remind you that he is much older than she is.
No one can tell you what to do....all I hope is that you can see from the above that it is possible for these pups to live with these conditions. Ultimately you are the one who must decide whether to try surgery or not. In Sammy's case the vets at Texas A&M felt that surgery would just open up a can of worms so to speak...they did not recommend it at all.
I will keep Cassie and you in my thoughts and prayers.