OVERVIEW OF GASTRIC BYPASS SURGERY

What is a gastric bypass surgery or Roux-en-Y surgery and why is it necessary?
Gastric bypass procedures (GBP) are any of a group of similar operations used to treat morbid obesity – the severe accumulation of excess weight as fatty tissue – and the health problems (co-morbidities) it causes. Gastric bypass surgery, which is also known as stomach stapling makes the stomach smaller and allows food to bypass part of the small intestine. This makes you feel full more quickly than when your stomach was its original size, which reduces the amount of food you eat and thus the calories consumed. Bypassing part of the intestine also results in fewer calories being absorbed. This leads to weight loss, typically dramatic and markedly reduces co-morbidities.

Although guidelines vary, surgery is generally considered when your body mass index is 40 or higher or you have a life-threatening or disabling condition related to your weight. Your doctor may consider doing gastric bypass surgery if you have been unable to achieve satisfactory and sustained weight loss by dietary efforts, and are suffering from co-morbid conditions which are either life-threatening or are a serious impairment to the quality of life.

The following conditions may also be considered:
•    You have been obese for at least 5 years.
•    You do not have a history of alcohol abuse.
•    You do not have untreated depression or another major psychiatric disorder.
•    You are between 18 and 65 years of age.

Who is a candidate for gastric bypass surgery?
If you have a body mass index (BMI) of 40 or more you are considered severely obese, and therefore become a candidate for surgery. Calculate your BMI .

Weight loss surgery may also be an option for people with a BMI between 35 and 40 who suffer from obesity-related problems (for example, severe sleep apnea, obesity-related heart disease, or diabetes). A person with a BMI of 30 or above is at a higher risk for certain diseases, including heart disease, high blood pressure, and coronary artery disease (CAD).

What are the different types of gastric bypass surgeries?
The variations of the gastric bypass surgery are:

•  Gastric bypass, Roux en-Y (proximal)
This is the most commonly performed gastric bypass technique. It is the operation which 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.

•  Gastric bypass, Roux en-Y (distal)
The normal small bowel is 600 to 1000 cm (20 to 33 feet) in length. As the Y-connection is moved farther down the Gastrointestinal tract, the amount of bowel capable of fully absorbing nutrients is progressively reduced, in pursuit of greater effectiveness of the operation. The Y-connection is formed much closer to the lower (distal) end of the small bowel, usually 100 to 150 cm (40 to 60 inches) from the lower end of the bowel, causing reduced absorption (mal-absorption) of food, primarily of fats and starches, but also of various minerals, and the fat-soluble vitamins. The unabsorbed fats and starches pass into the large intestine, where bacterial actions may act on them to produce irritants and malodorous gases. These increasing nutritional effects are traded for a relatively modest increase in total weight loss.

•  Loop Gastric bypass ("Mini-gastric bypass")
The Mini-Gastric Bypass, which uses the loop reconstruction, has been suggested as an alternative to the Roux en-Y procedure, due to the simplicity of its construction, which reduced the challenge of laparoscopic surgery. It is claimed that construction of a long tubular gastric pouch reduces the risk of inflammatory complications, and renders it as safe as the Roux en-Y technique.