This device was approved for use in the U.S. by the Food and Drug Administration (FDA) in 2001. The band is made of solid silicone, like a belt, and is wrapped around the upper part of the stomach. The belt has an inner inflatable balloon that is adjusted by adding sterile water to the port. The port is placed under the skin. When the band is inflated, it squeezes the stomach, making it harder for food to pass from the small upper stomach pouch through to the rest of the stomach. Food is forced to slow down and, therefore, the small pouch stretches. This makes you feel full after eating very small portions. If the band is too tight, food will get stuck and cause vomiting. In that case, the fluid can be removed by the doctor to relax the band and allow food to pass easier. Digestion is normal and your anatomy is kept intact, which makes the procedure reversible.
The "sleeve" is a procedure in which the majority of the stomach is stapled off and removed. This results in a long, slender stomach tube that doesn't stretch much. This procedure helps you eat small portions (4-8 ounces). It also has the added benefit of reducing hunger, partly due to the dramatic decrease in the hormone ghrelin which is primarily made in the part of the stomach that is removed. There may be other hormone changes that occur to help improve diabetes.
Roux-En-Y Gastric Bypass (RYGB)
This is still the most popular weight loss surgery in the U.S. With the bypass, nothing is removed but the anatomy is rearranged. First, a small one ounce stomach pouch is created. This is stapled and divided from the rest of the stomach and can only hold a few ounces of food. The remaining 95 percent of the stomach remains in place but no longer is able to receive food. This "bypassed" leftover stomach does not shrink, rot, or cause any problems. It still makes digestive juices.
Next, the small intestine is "rearranged." About two feet of small intestine is divided into three sections: the duodenum, jejunum, and ileum. The duodenum, where the majority of digestive juice is produced and nutrients are absorbed, is cut and connected to the jejunum three feet (100cm) down stream. The "free" or "cut" end is pulled up and connected to the pouch with a very small opening.
Now food enters the stomach pouch and squeezes through a small, button-sized opening to get into the intestine. The food travels three feet before it encounters the digestive juices produced by the bypassed stomach and duodenum. The overall effect is that patients eat small portions and calories do not absorb well (restriction plus malabsorption). In addition, because food bypasses the old stomach, 90 percent of diabetics are cured almost immediately after the operation.