Hi Jack, i am glad that they are on to this possibility, but i am surprised that this wasn't discussed or covered well before now, its normally checked well before this stage, this is why its so very important to make sure you have a PN expert to diagnose PN and not just a normal neuro, generally with PN any lower spinal pressure goes to your feet and cervical goes to your hands but even cervical pressure has been known to affect the feet, just to confuse us more.
I believe they have "stand up" MRI machines these days which can show another view of the spine whilst its in a upright position, were the older lay down MRI's can't.
I agree with Joe, if it was me, i would see a Neuro/chiroprator or any other alternate possibility and stay well clear of a surgeons knife.
good luck with it anyway mate,
Brian