Types of Gastric Bypass Surgery

The Gastric Bypass Surgery is the most commonly performed operation for weight loss in the United States. In the U.S, approximately 140,000 Gastric Bypass procedures were performed in 2005, an amount dwarfing the number of Lap-Band, Duodenal Switch and Vertical Banded Gastroplasty procedures performed. Furthermore, since Gastric Bypass has been performed for almost 50 years, surgeons have become more comfortable with the understanding of its risks and benefits. By sheer volume of cases combined with the volume of scientific research, the Gastric Bypass Surgery has become the “gold standard” operation for weight loss in the U.S.

One of biggest advancements in the Gastric Bypass operation has been the technique used to enter into the abdomen – the laparoscopic approach. Although the laparoscopic approach has a number of potential advantages over the traditional open operation, the training and expertise necessary to perform the laparoscopic approach safely is considerable.

The laparoscopic approach has a number of advantages.

  1. Generally 5 tiny incisions are necessary. Four are about ½” long and one is 1″ long. These incisions are too small for any significant infection to occur and the risk of developing a hernia is less than one percent. The risks of infection, wound problems and hernias are close to 30 percent with the traditional open procedure.
  2. The operation, in expert hands, can be performed quicker than an open operation. In fact, average operating room times are close to one hour. Less time in the operating room means less anesthesia and anesthesia-related complications.
  3. Less pain. Patients, although sore in the first few hours, need only Tylenol with Codeine the day after surgery. Many patients do not require any medications for pain by the time they go home.
  4. Quicker return to work. Patient can often return to work in one week. However, it is generally recommended to take two weeks off work to be on the safe side.
  5. Better operation. The operation is performed under magnification. Doctors are able to see details that are difficult in the open approach.
  6. As patients are walking the day of surgery and discomfort is easily controlled, patients are at lower risk to develop blood clots, pneumonia, bed sores or other complications resulting from prolonged immobility.

The Gastric Bypass Procedure (GBP) has been proven in numerous studies to have good long-term weight loss. The average weight loss often peaks at 18-24 months after surgery – but half of all the weight loss often occurs in the first six months. The Gastric Bypass Procedure, through multiple studies, has been shown to improve or cure diabetes, hypertension, arthritis, venous stasis disease, certain types of headaches, heartburn, sleep apnea and many other disorders. Most importantly, the Gastric Bypass Procedure has demonstrated significant improvements in the quality of the patient’s life.

Regardless of the entry technique (laparoscopic or open), most surgeons perform the operation in a very similar manner. The stomach is cut to form a small pouch (usually one ounce in size) and the remaining stomach and first 1-2 feet of small intestine are bypassed. In the standard Gastric Bypass Procedure, the amount of intestine bypassed is not enough to create malabsorption of proteins and other macronutrients. However, the bypassed portion of intestine is especially adept at absorbing calcium and iron – thus, anemia and osteoporosis are the most common long-term complications of the gastric bypass and must be prevented with lifelong mineral supplementation. Other clinically significant deficiencies have been identified such as thiamine and Vitamin B12. Lifelong follow-up with a bariatric program is mandatory to monitor and prevent nutritional complications. Most surgeons recommend specific supplements to prevent these long-term complications.

Unlike the Duodenal Switch, the Gastric Bypass Procedure does not require the removal of any part of the stomach. The unused stomach survives well with no demonstrable long-term problems. In fact, the unused stomach produces important enzymes. Intrinsic Factor, for instance, is crucial in the absorption of Vitamin B12 and is only made in the stomach.

Although the most commonly performed GBP (sometimes called the proximal bypass) involves little or no malabsorption, some surgeons modify the gastric bypass to incorporate a significant amount of malabsorption for the purpose of augmenting weight loss. This modification, called a distal gastric bypass, has significantly more nutritional complications than the proximal gastric bypass. Whether long-term weight loss is superior to the proximal GBP or whether the malabsorptive complications are worth the possible improvements in weight loss have not been well studied. Many surgeons reserve the distal GBP for very select circumstances.

The mechanism in which the gastric bypass works is complex. After surgery, patients often experience significant changes in their behavior. Most state that they do not get hungry frequently and that their hunger is fleeting. Patients often state that they enjoy healthy foods and lose many of their food cravings. Rarely do people feel deprived of foods. These complex behavioral changes are partially due to poorly understood alterations in the hormones and neural signals produced in the GI track that communicates with the hunger centers in the brain. One interesting hormone that has recently been studied is ghrelin. Certainly the small size of the stomach pouch restricts the volume of food people eat as well. Thus, the decrease in hunger and the rapid feeling of fullness accounts for most of the weight loss after a gastric bypass.

Another mechanism of weight loss after the Gastric Bypass Procedure is called dumping syndrome. Dumping syndrome causes the intolerance to sweets after surgery. Dumping may result in lightheadedness, flushing, heart palpitations, diarrhea and other symptoms immediately after eating desserts. Some people are extremely sensitive to sweets for the rest of their lives; other patients lose some or all of their sweet sensitivity over time. The exact mechanism of dumping syndrome is not entirely understood.

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