Depends on your demographic (certainly things cost more on the West Coast than in Kansas), testing necessary before surgery (i.e. myelogram or MRI), and how much spinal surgery is needed.
I could easily say over $3000, and could cross $4500 with post-care, medications, etc...
Greatly depends on the specialist.
You can use this link to find a neurologist near where you live for an evaluation:
Find Various Specialists
--> Under "specialty" select SAIM = Small Animal Internal Medicine
--> Or, you can search for a Neurologist, Cardiologist or Oncologist