Gastric Bypass


bypassGastric Bypass

The so-called Roux-en-Y gastric bypass (RGB) is the most commonly performed weight-loss operation all over world. It is considered as the ‘gold standard’ among all bariatric procedures.

The so-called Roux-en-Y gastric bypass (RGB) is the most commonly performed weight-loss operation all over world. It is considered as the ‘gold standard’ among all bariatric procedures. A Roux-en-Y stomach bypass can be performed laparoscopically or by using open surgery, and has three basic variants, depending on the length of intestine bypassed: Proximal RGB involves very little malabsorption of calories and nutrients; Medial RGB causes moderate malabsorption; and Distal RGB causes significant malabsorption.

How does it lead to weight loss?

Unlike in biliopancreatic diversion (BPD) or biliopancreatic diversion with duodenal switch (BPD/DS), during Roux-en-Y the bariatric surgeon does not remove the unused part of the stomach. Instead the stomach is transected, using gastric staples, into a small upper section (the pouch) and a larger lower section. The pouch is smaller than the one created during biliopancreatic diversion (one ounce, compared to 4-5 ounces). The lower section is then bypassed, together with the first part of the small intestine (duodenum and jejunum). Digested food now passes from the pouch directly into the lower part of the small intestine. The bypassed upper segment of the small intestine continues to carry digestive juices from both the stomach and pancreas and is re-connected to the “roux limb” lower down, forming the distinctive Y shape of the RGB.

Compared to BPD and BPD/DS, Roux-en-Y bypass operations are more restrictive (patients can eat less), but less malabsorptive (lower chance of nutritional deficiency). Lastly, RGB is reversible, as the stomach is divided or partitioned rather than the unused stomach being surgically removed as in the other bypass procedures.

 

Potential complications

Complications can be segmented into two groups: complications that relate to abdominal or laparoscopic surgery in general, and complications that relate specifically to gastric bypass surgery.
Complications from abdominal surgery can include:
– infection of the incisions or of the inside of the abdomen, or nosocomial infections (infections acquired in hospitals) such as pneumonia, bladder or kidney infections, and sepsis. Infection can often be prevented by gentle physical activity after surgery and treated with antibiotics
– blood loss, treated by a transfusion or re-operation
– incisional hernia, although the risk of abdominal wall hernia is markedly decreased in laparoscopic surgery
– bowel obstruction, which usually requires re-operation
– a venous thrombo-embolism (blood clot) floating to the lungs to cause a pulmonary embolus, although anti-coagulants (heparin) are commonly administered before and after surgery to reduce the risk

Complications from a gastric bypass can include:

Anastomotic leakage. This occurs in about 2% of gastric bypass procedures, usually at the stomach-bowel connection. Sometimes leakage can be treated conservatively, and sometimes it will require immediate re-operation
– Anastomotic stricture makes it difficult for food to pass through. This is corrected through gastrointestinal endoscopy whereby a balloon is inflated at the site of the narrowing
– Dumping syndrome is caused by the patient eating food with a high simple-sugar content which passes into the bowel too rapidly. This causes severe discomfort for approx. 30 to 45 minutes and may be followed by diarrhea.
– Nutritional deficiencies, including: hyperparathyroidism due to inadequate absorption of calcium; iron deficiency; protein malnutrition, especially if the patient suffers vomiting after surgery until their GI tract adjusts to the changes; and vitamin deficiency. These are all relatively easy to counter using high-quality protein, mineral and vitamin supplements