Oh Theresa, that is mostly good news about Em. When u say compression, do u mean narrowed disc space? If so, then maybe he has a bulged or prolapsed disc, which pushes on the sciatic nerve (depending on disc, eg: L5/S1). Hope he gets some relief soon though. Yikes, MRI's are really expensive aren't they, but at least it will provide him with more answers.

Anna, hope a GP can give u some more answers.