Stomach Bypass

Gastric bypass is a serious gastrointestinal operation to treat severe clinical obesity. The gastric bypass is the most commonly performed type of bariatric surgery in America: roughly 140,000 stomach bypass operations were performed in 2005, a far higher number than the combined total of gastric banding or gastroplasty procedures. Bariatric surgeons have been operating on morbidly obese patients, using various forms of gastric bypass, for almost 50 years. As a result, much is known about the risks, perioperative and post-operative health complications, and benefits of the operation.

What Does Stomach Bypass Involve? How Does It Work?

During a gastric bypass operation the surgeon does two basic things: (1) He reduces the size of the stomach. Either by using gastric staples (as in Roux-en-Y bypass) or by use of a gastric silastic ring (as in fobi pouch bypass), or by gastrectomy – surgical removal (as in biliopancreatic diversion, or the 2-stage Sleeve Gastrectomy bypass). (2) He connects the remaining stomach pouch to the lower part of the small intestine (usually the lower section of the jejunum) bypassing the duodenum and a varying length of the jejunum. Reducing the stomach size (the “restrictive” part of the operation) forces patients to eat less food. Their new stomach pouch cannot accomodate more than a few mouthfuls and they are rapidly satisfied. Bypassing the duodenum and a significant part of the jejunum (a total of up to five feet of small intestine) – the “malabsorption” part of the procedure – reduces the amount of calories and nutrients the body can digest. The combined effect is to drastically reduce the number of calries consumed, thus causing rapid weight loss.

What Are The Main Types of Gastric Bypass?

The most common types of stomach bypass procedure include: Roux-En-Y (RGB), Biliopancreatic Diversion (BPD), Biliopancreatic Diversion With Duodenal Switch (BPDDS). All three bypasses may be performed using the traditional ‘open’ method of surgery, or by ‘keyhole’ techniques, known as laparoscopy. The 2-stage Sleeve Gastrectomy, a procedure for super-obese patients (BMI >60) involving the removal of two thirds of the stomach (step 1), followed by a gastric bypass (step 2) is also attracting attention.

Does Gastric Bypass Help To Reduce Obesity

Yes. Stomach bypass surgery typically leads to significant post-operative weight loss, and may be considered a very effective treatment for severe obesity. Patients who undergo gastric bypass can lose up to 75 percent of their initial excess weight within two years following the operation. In one patient study of 125 subjects, (not necessarily typical) the average excess weight lost was 74 percent (year 1), 78 percent (year 2), 81 percent (year 3), 84 percent (year 4), and 91 percent after 5 years. That said, gastric bypass is only successful when patients follow the dietary guidelines given them by their weight loss surgeon. Despite the fact that malabsorptive surgery like gastric bypass makes it more difficult for patients to “cheat”, some individuals find the post-operative diet regime too arduous and regain weight after five years.

Biliopancreatic Diversion Gastric Bypass (BPD)

This stomach bypass (Scopinaro procedure) is a more extreme procedure. A large part of the stomach is removed, reducing both food intake and stomach acid production. The new stomach holds 4-5 ounces. Food is re-routed (via the “biliopancreatic limb”), bypassing the entire length of the duodenum and jejunum. At the same time, bile and pancreatic juices are channeled through a second limb (“alimentary limb”) which joins and forms a common digestive tract with the biliopancreatic limb, allowing calorie and nutritional absorption to occur. Bariatric surgeons can vary the length of this tract to regulate the intake of fat, protein and fat-soluble vitamins. Even so, both calorie and nutrient absorption is severely reduced. Not surprisingly, the Biliopancreatic Diversion Gastric Bypass is extremely effective for weight reduction, although nutritional deficiency is a lifelong problem and patients require continuous nutritional supplementation. Some bariatric clinics no longer perform biliopancreatic bypasses due to this severe malabsorption. Paradoxically, although biliopancreatic diversion patients absorb less calories/nutrients than Roux-en-Y bypass patients, they can actually eat more. This is because the resized biliopancreatic stomach holds 4-5 times more than the resized Roux-en-Y stomach.

Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

This stomach bypass variant of the regular biliopancreatic bypass leaves a larger portion of the stomach intact, including the pyloric valve which regulates the release of stomach contents into the small intestine. This usually helps the patient to avoid “dumping syndrome” – the unpleasant, nauseous result of eating sweet foods or concentrated sugars, after surgery. However, like the regular biliopancreatic bypass, Duodenal Switch Gastric Bypass has a high malabsorptive element and patients require nutritional supplements for life. In addition, like BPD, the BPD/DS involves surgical excision of a large part of the stomach, making the operation irreversible.

Roux-en-Y Gastric Bypass (RGB)

This stomach bypass operation is seen as the ‘gold standard’ by many bariatric centers. Roux-en-Y Gastric Bypass has the highest long-term success rate and comparatively low rates of complications and failures. 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 malabsorbtion of calories and nutrients. Medial RGB causes moderate malabsorbtion, while Distal RGB causes significant malabsorbtion. By comparison with BPD and BPD/DS bypasses, during Roux-en-Y the bariatric surgeon does not remove the unused part of the stomach. Instead the stomach is transected, using gastric staples, sinto a small upper section (the pouch) and a larger lower section. However the pouch is smaller than the one created during biliopancreatic diversion – one ounce, compared with 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 (smaller danger of nutritional deficiency). Roux patients may also experience ‘dumping syndrome’. Lastly, RGB is reversible, as the stomach is divided or partitioned – unlike the other bypass procedures where the unused stomach is surgically removed.

Health Risks And Complications Of Gastric Bypass

The health complications associated with stomach bypass vary according to: the health and physical condition of the patient; the complexity of the bypass operation; the skill/experience of the surgeon and anesthetist; post-operative patient compliance and the level of support received. But in general, all candidates for gastric bypass operations should realize that these procedures are not cosmetic surgery – they are very serious medical operations, performed under general anesthesia and carry a number of health dangers. These risks should be balanced against the well-documented medical dangers of extreme overweight.

Medical Health Complications After Gastric Bypass

There are no definitive statistics on health risks associated with stomach bypass surgery. The following figures are sourced from general studies of bypass operations. About 1 in 3 bypass patients develop gallstones. [Note: some bariatric surgeons prefer to remove the gallbladder during the initial surgery.] About 1 in 5 patients suffer from post-operative gastrointestinal symptoms including nausea, vomiting, diarrhea, bowel complaints, dysphagia, and reflux (20 percent). About 1 in 8 suffer from anastomotic leaking from stitches connecting the stomach and the intestine. About 1 in 14 patients suffer from abdominal hernia, while 1 in 16 incur an infection. Nutritional deficiencies, caused by the malabsorptive part of the bypass operation, are common to all bypass patients. In general, the longer the length of small intestine bypassed, the fewer nutrients which can be absorbed and the greater the deficiency. For instance, a Distal Roux-en-Y procedure causes more nutritional deficiency than a Proximal Roux-en-Y. However, supplementation eliminates this nutritional problem. Life-threatening health complications are rarer, and death rates are considerably lower than 1 percent. However, up to 1 in 5 bariatric patients need a second operation to correct health complications arising from the first procedure: abdominal hernias are most common. In general, bypass operations carry greater health risks than those for Adjustable Gastric Banding (such as Lap-Band), or Vertical Banded Gastroplasty.

Other Post-Operative Complications

Dumping Syndrome
This problem occurs when food passes too quickly from the reduced stomach pouch into the small intestine, something which is more less likely to occur if the pyloric valve – which regulates food flow out of the stomach – is left intact. Too rapid stomach emptying causes a release of adrenalin, leading to symptoms such as nausea, palpitations, sweating and diarrhea.

Eating Habits After Gastric Bypass
After surgery, patients are obliged to make a drastic change to their normal eating habits. Their stomach has been shrunk from the size of a large pineapple (capable of significant expansion), to the size of a small egg, or even smaller. Only liquids may be taken at first. Over the following weeks, semi-solid and then solid food may be added to the diet. For the bypass to be successful in achieving medium and long term weight reduction, it is essential that patients comply fully with their new post-bypass dietary guidelines.

Loose Skin After Gastric Bypass
Massive weight loss is inevitably followed by the accumulation of unsightly loose skin around the neck, arms, abdomen and thighs. Plastic surgery operations, such as face/neck lift, breast lift, abdominoplasty (tummy tuck) and lower body lift, can help to remove this loose skin, as well as any pockets of remaining fatty tissue. However, such procedures are regarded as ‘cosmetic’ rather than medical, and are not covered by medical insurance.