Steve,
I feel so bad for you, facing another difficult surgery with the disadvantages of fusion.  
I think the question still remains, are you going to go with Dr. R or will you allow the new Dr. M do your surgery with a consult from Dr. R?  Also, when is the biggest question?
Well life is full of ups and downs.  This is your down which I'm sure will be followed by a very long up

.
You are very definitely in my thoughts, Dale