It would be ideal if they could release an audio of his accent. People from certain parts of the country could place it and narrow down the search field perhaps. I have heard of people with amnesia developing a psuedo accent, but this may not pertain to him.
If there are pins or plates present in his elbow, would they not also contain numbers which could be traced? I don't know how one would go about obtaining the numbers short of exploratory surgery, but it is a thought.
Wouldn't it be clear in x-rays if he had a cervical repair on his neck? If not, could the surgery have been for other reasons such as thyroid? Has there been an effort to contact the AMA in possibly tracking down a surgeon who may have performed the work on either his neck or elbow?