I agree with Laura (see your surgeon as a first step to see of there is something mechanically wrong that might be able to be corrected) and with Kelly (determining what you are doing -- or not doing -- that is causing the weight gain is a better option than another surgery, especially one so flawed as the Lap Band).
Personally, I would not consider another surgery. The band has too many complications and I would not submit myself to the additional malabsorption of vitamins associated with the DS. Unless you have significantly stretched your pouch or stoma, you already have a weight loss tool that works. I am almost 5 years out and generally maintaining at my "bounce weight" (5-7 pounds above my lowest weight), but have a 5 pound gain threshold; when I hit that, I go back to basics and get it back off. I increase my protein and water, pay more attention to portion sizes, and eliminate as many of the non-dairy carbs as possible. That enables me to get the 5 pounds off in 2 or 3 weeks. There is no reason that the same approach would not work for you. It is very easy to let too many carbs creep in and to have your portion sizes slowly increase until you are eating more calories than you think or intend. Even with another surgery you would need to figure out what you were doing that is causing the regain or you would likely face regain again down the road even after another surgery.
8 years out; 190 pounds lost!
“You don't drown by falling in the water. You drown by staying there.”