Hello, looking for advice here because we are baffled. Our 3 year old Romanian rescue dog - (think medium German Shepherd / collie / husky - is best description), very occasionally suffers from an almost complete inability to move his back legs and cries in pain, has to be carried outside etc. This will last a few hours and then miraculously he leaps back to life and will tear round our local woods chasing pigeons, leaping over fallen trees and generally behaving like a very fit young dog should. Our local vet is stumped. Has anyone experienced anything similar or have any suggestions as to what it might be. Thanks in advance.