Bariatric surgery promotes weight loss by changing the digestive system's anatomy, limiting the amount of food that can be eaten and digested.
Obesity normally is defined through the use of body mass index (BMI) measurement. Physician offices, obesity associations, nutritionists, and others offer methods for calculating BMI, which is a comparison of height to weight. Those with a BMI of 30 or higher are considered obese. However, at 40 or higher, they are considered severely obese—approximately about 100 pounds overweight for men and 80 pounds overweight for women.
Many people who are obese struggle to lose weight through diet and exercise
but fail. Only after they have tried other methods of losing weight will they be candidates for bariatric surgery, which today is considered a "last resort" for weight loss. In general, guidelines agree that those with a BMI of 40 or more, or a BMI of 35 to 39.9 and a serious obesity-related health problem, qualify for bariatric surgery. More than 23 million Americans are candidates for bariatric surgery. More than 100,000 of the procedures were performed in 2003 and the number of surgeries performed will probably continue to rise for many years.
Bariatric surgery is not for everyone and the surgeon and other physicians will evaluate all medical conditions before allowing a patient to proceed. As a major surgery, there are associated risks and side effects. Women of childbearing age should be aware that rapid weight loss and nutritional deficiency associated with bariatric surgery may be harmful to a developing fetus. It is important that a patient reveal all current medications and conditions during any pre-operative discussions or examinations. Also, the physician will carefully evaluate the patient to ensure that he or she is prepared to make a lifelong commitment to the changes in eating and lifestyle required to make the surgery successful.
Though many studies have shown general safety associated with the major surgeries, they are relatively new and research on long-term effects are not as widespread as they are for many other surgeries and procedures. When choosing a surgeon to perform the operation, patients should check with organizations such as the American Society for Bariatric Surgery for certification. A patient also should ask about the surgeon's experience in performing the particular operation.
Although the number of obese teenagers and resulting bariatric surgeries has increased, some experts are questioning the decision to perform bariatric surgery on teens. There are no specific clinical guidelines for determining a safe age for the procedure, but some physicians agree that bariatric surgery is not appropriate for children younger than age 15, since they are still growing and forming bones.
When food is chewed and swallowed, it moves along the digestive tract. In the stomach, a strong acid helps break down food so it can be digested and the body can absorb the food's nutrients and calories. The stomach can hold about three pints of food at one time. As digestion continues, food particles become smaller and move from the stomach into the intestine. The various parts of the small intestine are nearly 20 feet long if laid out straight. Those food particles not digested in the small intestine are stored in the large intestine until they are eliminated as waste.
When a patient has bariatric surgery, this digestive process is altered to help the patient lose weight. There are three main types of bariatric surgery, but only two types are commonly used today. The types are restrictive, malabsorptive, and combined restrictive/malabsorptive.
Restrictive surgery, often referred to as "stomach stapling" uses bands or staples to create a small pouch at the top of the stomach where food enters from the esophagus. This smaller pouch may hold only about 1 ounce of food at first and may stretch to hold about 2-3 ounces. The pouch's lower opening is made small, so that food moves slowly to the lower part of the stomach, adding to the feeling of fullness. The most frequently performed types of restrictive surgeries are vertical banded gastroplasty (VBG), gastric banding, and laparoscopic gastric banding. VBG is used less today in favor of gastric banding, which involves an adjustable hollow band made of silicone rubber.
Laparoscopic gastric banding, or Lap-band, was approved by the U.S. Food and Drug Administration (FDA) in 2001. Sometimes referred to as "minimally invasive" bariatric surgery, the surgeon uses small incisions and a laparoscope, or a small, tubular instrument with a camera attached, to see inside the abdomen and apply the band.
Malabsorptive procedures help patients lose weight by limiting the amount of nutrients and calories the intestine can absorb. Sometimes called intestinal bypasses, they are no longer used in the United States because they have often resulted in severe nutritional deficiencies.
— The organs that perform digestion, or changing of food into a form that can be absorbed by the body. They are the esophagus, stomach, small intestine, and large instestine.
— A muscular tube about nine inches long that carries food from the throat (pharynx) to the stomach.
Combined restrictive/malabsorptive operations are the most common bariatric surgeries. They work by restricting both the amount of food the stomach can hold and the amount of calories and nutrients the body absorbs. The most common and successful combined surgery in recent years is called the Roux-en-Y gastric bypass (RGB). In this operation, the surgeon first creates a small pouch at the top of the stomach. Next, a Y-shaped section of the small intestine is connected to the small pouch, allowing food to bypass the lower stomach, the first part of the small intestine (duodenum), and the first portion of the next section of the small intestine (jejunum). It connects into the second half of the jejunum, reducing the amount of calories and nutrients the body absorbs. RGB may be performed with a laparoscope and a series of tiny incisions or with a large abdominal incision.
Procedure times vary, depending on the type of bariatric surgery chosen. However, most patients are in surgery for about one to two hours. Though costs can be as high as $35,000, more insurance companies are beginning to pay for the procedures if they are proven medically necessary. In 2004, the agency that pays for Medicare costs recognized obesity and many of its treatments as a medical cost for the first time, recognizing that obesity leads to many other medical problems.
The physician will first make sure that a patient is mentally prepared for the surgery and the commitment to follow-up care that will be required. Patients should have a consultation appointment with the surgeon prior to the procedure to discuss risks and benefits. Pre-operative instructions will be given that will tell the patient specific preparations prior to the surgery. These may include instructions about avoiding food or liquids, certain medications, and other instructions on the day before or the day of the procedure. Patients also may have several laboratory or other diagnostic tests prior to the surgery.
Depending on the type of procedure and any possible complications, patients can expect to stay at the hospital or surgery center for about two to four days following the surgery. Those who have laparoscopic operations typically have shorter hospital stays and speedier recovery times. The physician and nurses will provide instructions for wound care and other follow-up when the patient is discharged from the hospital. Usually, bariatric surgery patients can resume normal activity within about six weeks following surgery, and as little as two weeks after laparoscopic procedures. It is important for bariatric surgery patients to lose weight at the recommended pace, take nutritional supplements
as recommended, and attend follow-up visits with physicians and nutritionists.
How a patient complies with instructions from physicians following bariatric surgery is important. Most patients will require lifelong use of nutritional supplements such as multivitamins, calcium, and other vitamin supplements to prevent nutritional deficiencies. Because the stomach is smaller, patients will have to eat small portions of food and often must avoid certain types of food such as sugar.
The surgeon performing the procedure should discuss its specific risks prior to surgery. Risks for bariatric surgery include infection, blood clots
, abdominal hernia
, gallstones, nutritional deficiencies, possible nerve complications, and death
. Death rates have been reported lowest for RGB and VBG, at less than 1% of patients.
Weight loss will occur gradually, as patients can eat less food and absorb fewer calories. When patients follow post-operative instructions, they can lead normal lives, eating less food and being careful to limit certain foods that may irritate their new stomach pouches. Most patients will lose 50-60% of their excess weight in the first year or two. With gastric bypass surgery, many can lose up to two-thirds of excess weight by the second postoperative year.
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Santora, Marc. "Teenagers Turn to Surgery to Shrink Their Stomachs." The New York Times (Nov. 26, 2004):B1.
American Obesity Association. 1250 12th St. NW, Suite 300, Washington, DC 20037. 202-776-7711. http://www.obesity.org.
Society of American Gastrointestinal Endoscopic Surgeons. 11300 West Olympic Blvd., Suuite 600, Los Angeles, CA 90064. 310-437-0544. http://www.sages.org.
Gastrointestinal Surgery for Severe Obesity Weight-control Information Network, National Institutes of Health, 2004. http://win.niddk.nih.gov/publications/gastric.htm.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.