Medicare will cover it. They typically want you to go to an approved facility, Centers of Excellence. So make sure you look up that on wherever you go. Not all docs take Medicare. Make sure you find out your deductible too. Some docs try to get people to pay them more than they are supposed to. For example they will tell you they have a package deal. No way. Your insurance will pay for dietician and all other BS. They just want $. I have known of others who had arthritis, type 2 diabetes, sleep apnea and many other things getting Medicare approval. Dont give up. The surgeon should fight it for you. Dont be surprised if you are asked to undergo lots of testing. You probably will not be able to go to an outpatient surgery center. So make sure the hospital has a good follow up program, like support groups and band adjustments. Also find out how long your doc has been doing the band or whatever your having one and how involved are they with general surgery. Dont want some slacker cuttin on ya. You want that doc who will save you if something "funny" happens.
Best wishes.