The vet took xrays which showed that his hips are in great shape and the only thing he noticed was some calcification between a couple of vertebrae that might be an indicator of a bulging disk. The problem was definitely neurological and it was either a disk pressing on the nerves or a condition called degenerative myelopathy (DM). He referred me to a orthopedic specialist who I saw on Thursday. He confirmed what my vet had told me. If it was a disk I was looking at about $2000 for corrective surgery, but if it was DM then there was nothing that could be done.
When I got back to work I looked up DM and discovered that it is fairly common and almost exclusive to GSDs. It was the first I'd heard of it. In a nutshell it is like MS in people. It is a disease that attacks the nerves in the spinal column starting with the rear legs and rapidly progresses until the hind legs are paralyzed and eventually the dog dies.
The way the condition is progressing, I'm 99% sure that Scout has DM. His symptoms are rapidly worsening. He has difficulty going up and down stairs and frequently trips or stumbles. His legs cross under him when he is walking slowly and when he is standing it isn't uncommon for his hind legs to just slide out from underneath him. If it's DM then in a short time, 3 to 6 months, he'll become incontinent and completely lame. Before it gets too bad I'll have the difficult task of saying goodbye to a dear friend and putting him down.