My dog has rear nerve damage how can we fix it alternatly without operation?

well like the questin says she is a 7 year old beagle who at frst got diagnosed with shifting limb syndrom then they exrayed and a small protusing on lower spine also ran full blood test to no avail,they finally said ,actually it was the vets dadd that said it could be the nervge andmy wife said i think they can sever it or something deaden it ,is this bad and is there an alternetive method ,she currently has to have tramadole every 2nd day just to walk what should we do been 3-6months trying everything but have monaictions ey restr