Welcome! We do see quite a few revisions where folks get the DS to add to the VSG, and some who also need to have the sleeve tightened at the same time. Insurance wise, do you qualify again based on BMI or can you go it on your own?
We are seeing more people looking into revisions from VSG to DS all the time, and on this forum we don't even see the ones revising to gastric bypass. It's the nature of the sleeve that, over time, it will stretch out. It will never be as large as the original stomach, but it's going to enlarge no matter how narrow it starts out, and when (not if) that happens, restriction is lost. Since restriction is the mechanism by which a sleeve works, once it stretches out you are left with, well, nothing to help you maintain your weight loss.
Check your insurance and see what revisions are covered, if any, and under what cir****tances. You will need a copy of your EOC (Evidence of Coverage), a LONG and detailed document and not just a summary of benefits. There are some policies that have "one surgery per lifetime" provisions, which I personally believe should not be legal, but apparently they are. You may or may not have appeals rights, which will also be in the EOC.
As Larra said, of course your sleeve stretched! Now, it hasn't stretched nearly as large as your stomach once was, but you should be able to get enough nourishment in now without depending on protein drinks. The sleeve got respect from the 2-part DS patients that lost all of their weight with just the first part (the sleeve), and didn't return to finish the job. Some lucky ones can stop there, while others need the whole thing.
That being said, without the benefit of the DS, you're back to dieting again and watching what you eat. Even if you were to simply tighten your sleeve, you may be subject to this again down the road. Are you still at least a 40 BMI (or 35 with comorbs)? If your insurance doesn't have a lifetime limit for WLS, you may qualify.
11 years post op DS
There is room on this earth for all of God's creatures..next to the mashed potatoes
Can it be tightened? Yes. SHOULD it be tightened? Much tougher question. A re-sleeve is much higher risk than the original sleeve, because the surgeon has to be sure to remove the entire old staple line to prevent stapling over the old staples, which can leave a small area with an insufficient blood supply, which can cause a leak - a very serious complication.
Also, without taking a look at your sleeve, who knows if a stretched out sleeve is the reason for your regain? Maybe your alimentary and common channels were created longer than usual, or at least too long for you. And is it worth it to undergo major surgery with significant risks over 30 lbs?
All in all this isn't a simple question and it might be helpful to get in touch with your surgeon and see what your alternatives are.
And to answer your other question, I have no idea if any kind of revision would be covered by Medicare.