Proximal gastric banding is
the most commonly employed gastric bypass technique for weight
reduction surgery,
and is the most commonly performed bariatric procedure in the
United States. It's popularity is due to the fact that it is least
likely to result in
nutritional difficulties. The small bowel is divided about 45 cm
(18 in) below the lower stomach outlet, and is re-arranged into a
Y-configuration, to enable outflow of food from the small upper stomach
pouch, via a "Roux limb". In the proximal version, the Y-intersection
is formed near the upper (proximal) end of the small bowel. The Roux
limb is constructed with a length of 80 to 150 cm (30 to 60 inches),
preserving most of the small bowel for absorption of nutrients. The
patient experiences very rapid onset of a sense of stomach-fullness,
followed by a feeling of growing satiety, or "indifference" to food,
shortly after the start of a meal. The "distal" variant of this
procedure basically attaches the Y-intersection more distally on the
small intestine, almost near the end. This, as one might
guess, has a higher incidence of nutritional deficiencies.