While Insurance will pay for a procedure if it is "medically necessary", it is almost impossible to demonstrate necessity in regards to arms.
Those of you who have seen me speak at support groups may have heard this story before....It is the only example that I have heard of where insurance has deemed an armlift as "medically necessary." It is not a patient of mine, and I believe it was in the state of NY:
A woman worked in a kitchen and sustained a burn to her upper arm because the excess skin touched a hot pot while cooking. She appealed to her insurance company claiming that it interfered with her work and was a danger to her. Only after 3 visits to an emergency department for treatments of these burns, did her insurance company agree that it was medically necessary.
This should demonstrate how difficult it is to have arms covered by insurance. If anyone has any success stories, I would be interested in hearing them.