Hi
I think you have syringomyelia, when they write the reports of RXs and other studies they always use terminology like the one you citated. Beyond the fact that your health insurance does not cover your surgery (according to the surgeon you visited) perhaps you could get a second opinion. Do you have a social worker working on your case? I am asking this because once while in the US I needed a very expensive practice. First it stemmed I would not get coverage for it but then a hospital social worker took my case, she fought for me, and finally the health insurance paid for it.
Have you make the decision to have the surgery or you have doubts on it?
Best wishes