Have you checked in Dr. Boyce in Knoxville? I'm not sure if they accept medicare, you would need to call. He is one of the few surgeons in the country who do a revision from rny to ds. the revision to a ds is the only type of surgery that can help someone who's had a rny. you have to take many more vitamins than the rny but the results are stronger and more lasting.
I'm in the middle of waiting to get approved for the surgery.