Bariatric surgery, or weight loss surgery, is a type of procedure performed on people who are dangerously obese, for the purpose of losing weight. This weight loss is usually achieved by reducing the size of the stomach with an implanted medical device (gastric banding) or through removal of a portion of the stomach (
gastric bypass surgeryGastric bypass procedures 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 it causes...
).
Long-term studies show the procedures cause significant long-term loss of weight, recovery from diabetes, improvement in cardiovascular risk factors, and a reduction in mortality of 23% to 40%.
The U.S. National Institutes of Health recommends bariatric surgery for obese people with a
body mass index (BMI)The body mass index , or Quetelet index, is a controversial statistical measurement which compares a person's weight and height. Though it does not actually measure the percentage of body fat, it may be a useful tool to estimate a healthy body weight based on how tall a person is...
of at least 40, and for people with BMI 35 and serious coexisting medical conditions such as diabetes.
Indications
A medical guideline by the
American College of PhysiciansThe American College of Physicians is a national organization of doctors of internal medicine , physicians who specialize in the prevention, detection and treatment of illnesses in adults. With more than 120,000 members, ACP is the largest medical-specialty organization and second-largest...
concluded:
- "Surgery should be considered as a treatment option for patients with a BMI
The body mass index , or Quetelet index, is a controversial statistical measurement which compares a person's weight and height. Though it does not actually measure the percentage of body fat, it may be a useful tool to estimate a healthy body weight based on how tall a person is...
of 40 kg/m 2 or greater who instituted but failed an adequate exercise and dietDieting is the practice of ingesting food in a regulated fashion to achieve or maintain a controlled weight. In most cases the goal is weight loss in those who are overweight or obese, but some athletes aspire to gain weight...
program (with or without adjunctive drug therapy) and who present with obesity-related comorbid conditions, such as hypertension, impaired glucose tolerance, diabetes mellitus, hyperlipidemia, and obstructive sleep apnea. A doctor–patient discussion of surgical options should include the long-term side effects, such as possible need for reoperation, gallbladder disease, and malabsorption."
- "Patients should be referred to high-volume centers with surgeons experienced in bariatric surgery."
Predominantly malabsorptive procedures
Predominantly
malabsorptiveMalabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal tract.Impairment can be of single or multiple nutrients depending on the abnormality...
procedures, although they also reduce stomach size, these operations are based mainly on creating malabsorption.
Biliopancreatic diversion
This complex operation is also known as
biliopancreatic diversion (BPD), or
Scopinaro procedure. This surgery is rare now because of problems with malnourishment. It has been replaced with the
Duodenal switchThe Duodenal Switch procedure, also known as Biliopancreatic Diversion with Duodenal Switch or Gastric Reduction Duodenal Switch , is a weight loss surgery procedure that is composed of a restrictive and a malabsorptive aspect....
, also known as the BPD/DS. Part of the
stomachIn most mammals, the stomach is a hollow, muscular organ of the gastrointestinal tract , between the esophagus and the small intestine. It is involved in the second phase of digestion, following mastication . The word stomach is derived from the Latin stomachus, which derives from the Greek word...
is resected, creating a smaller stomach (however after a few months the patient can eat a completely free diet as there is no restrictive component). The distal part of the
small intestineIn vertebrates, the small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where the vast majority of digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large...
is then connected to the pouch, bypassing the
duodenumThe duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum...
and
jejunumThe jejunum is the middle section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum...
.
In around 2% of patients there is severe
malabsorptionMalabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal tract.Impairment can be of single or multiple nutrients depending on the abnormality...
and nutritional deficiency that requires restoration of the normal absorption. The malabsorptive effect of BPD is so potent that those who undergo the procedure must take
vitaminA vitamin is an organic compound required as a nutrient in tiny amounts by an organism. The term 'vitamin' first became popular in the early 1800's as a contraction of the words 'vital' and 'mineral', though the actual meaning of the word has developed somewhat since that time...
and
dietary mineralDietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen present in common organic molecules...
s above and beyond that of the normal population. Without these supplements, there is risk of serious deficiency diseases such as
anemiaAnemia is a decrease in normal number of red blood cells or less than the normal quantity of hemoglobin in the blood...
and
osteoporosisOsteoporosis is a disease of bone that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is disrupted, and the amount and variety of non-collagenous proteins in bone is altered...
.
Because
gallstoneIn medicine, gallstones are crystalline bodies formed within the body by accretion or concretion of normal or abnormal bile components.Gallstones can occur anywhere within the biliary tree, including the gallbladder and the common bile duct...
s are a common complication of the rapid weight loss following any type of bariatric surgery, some surgeons remove the
gallbladderThe gallbladder is a small non-vital organ that aids in the digestive process and stores bile produced in the liver.-Human anatomy:...
as a preventative measure during BPD. Others prefer to prescribe
medicationA pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
s to reduce the risk of post-operative gallstones.
Far fewer surgeons perform BPD compared to other weight loss surgeries, in part because of the need for long-term nutritional follow-up and monitoring of BPD patients.
Jejunoileal bypass
This procedure is no longer performed.
Predominantly restrictive procedures
Predominantly restrictive procedures primarily reduce stomach size.
Vertical Banded Gastroplasty
In the
vertical banded gastroplastyVertical banded gastroplasty , also known as stomach stapling, is a restrictive operation for weight control. Both a band and staples are used to create a small stomach pouch...
, also called the Mason procedure or stomach stapling, a part of the stomach is permanently stapled to create a smaller pre-stomach pouch, which serves as the new stomach.
Adjustable gastric band
The restriction of the stomach also can be created using a silicone band, which can be adjusted by addition or removal of saline through a port placed just under the skin. This operation can be performed laparoscopically, and is commonly referred to as a "
lap bandA laparoscopic adjustable gastric band also known as a Lap-Band, is an inflatable silicone device that is placed around the top portion of the stomach, via laparoscopic surgery, in order to treat obesity...
." The first gastric band was patented in 1979 and successfully applied in animal experiments. An American company, INAMED Health, later designed the
BioEnterics LAP-BAND Adjustable Gastric Banding System, which was introduced in Europe in 1993. Neither of these bands was initially designed for use with laparoscopic surgery. The LAP-BAND System received U.S. Food and Drug Administration (FDA) approval in June 2001. In 2000, a lower pressure, wider, one-piece adjustable gastric band called the
MIDband was introduced by Medical Innovation Development of Lyon France. In 2002, a lower pressure, wider, one-piece adjustable gastric band called the
Bioring designed specifically for laparoscopic insertion was introduced in France by Cousin-Biotech, and swiftly become one of the leading bands in that country. There are now a number of band manufacturers.
Mixed procedures
Mixed procedures apply both techniques simultaneously.
Gastric Bypass Surgery
The most common form of
gastric bypass surgeryGastric bypass procedures 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 it causes...
is the Roux-en-Y gastric bypass. Here, a small stomach pouch is created with a stapler device, and connected to the distal small intestine. The upper part of the small intestine is then reattached in a Y-shaped configuration.
The gastric bypass is the most commonly performed operation for weight loss in the United States, and approximately 140,000 gastric bypass procedures were performed in 2005, dwarfing the number of Lap-Band, duodenal switch and vertical banded gastroplasty procedures. Since the gastric bypass has been performed for almost 50 years, surgeons have become very comfortable with, and aware of, the risks and benefits of the procedure. The gastric bypass operation has become the "gold standard" in the U.S. for comparison with new procedures. A factor in the success of gastric bypass surgery is strict post-surgical adherence to a
gastric bypass dietGastric bypass procedures 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 it causes...
.
Sleeve gastrectomy with duodenal switch
A variation of the biliopancreatic diversion includes a
Duodenal switchThe Duodenal Switch procedure, also known as Biliopancreatic Diversion with Duodenal Switch or Gastric Reduction Duodenal Switch , is a weight loss surgery procedure that is composed of a restrictive and a malabsorptive aspect....
. The part of the
stomachIn most mammals, the stomach is a hollow, muscular organ of the gastrointestinal tract , between the esophagus and the small intestine. It is involved in the second phase of digestion, following mastication . The word stomach is derived from the Latin stomachus, which derives from the Greek word...
along its greater curve is resected. The stomach is "tubulized" with a residual volume of about 150 ml. This volume reduction provides the food intake restriction component of this operation. This type of gastric resection is anatomically and functionally
irreversible. The stomach is then disconnected from the duodenum and connected to the distal part of the
small intestineIn vertebrates, the small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where the vast majority of digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large...
. The duodenum and the upper part of the small intestine are reattached to the rest at about 75-100 cm from the
colonThe colon is the last portion of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body....
.
Implantable Gastric Stimulation
This procedure where a device similar to a heart pacemaker is implanted by a surgeon, with the electrical leads stimulating the external surface of the stomach, is being studied in the USA. Electrical stimulation is thought to modify the activity of the
enteric nervous systemThe enteric nervous system is a subdivision of the Peripheral Nervous System, that directly controls the gastrointestinal system.It is derived from neural crest.-Function:...
of the stomach, which is interpreted by the brain to give a sense of satiety, or fullness. Early evidence suggests that it is less effective than other forms of Bariatric Surgery.
Eating after bariatric surgery
Immediately after bariatric surgery, the patient is restricted to a clear liquid diet, which includes foods such as clear broth, diluted fruit juices or sugar-free gelatin desserts. This diet is continued until the gastrointenstinal tract has recovered somewhat from the surgery. The next stage provides a blended or pureed sugar-free diet for at least two weeks. This may consist of skimmed milk, cream of wheat, a small pat of margarine, protein drinks, cream soup, pureed fruit and mashed potatoes with gravy.
Post-surgery, overeating is curbed because exceeding the capacity of the stomach causes
nauseaNausea is the sensation of unease and discomfort in the stomach with an urge to vomit.-Causes:...
and
vomitingVomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Undesired vomiting may result from many causes, ranging from gastritis or poisoning to brain tumors, or elevated intracranial pressure...
. Diet restrictions after recovery from surgery depend in part on the type of surgery. Many patients will need to take a daily
multivitaminA multivitamin is a preparation intended to supplement a human diet with vitamins, dietary minerals and other nutritional elements. Such preparations are available in the form of tablets, capsules, pastilles, powders, liquids and injectable formulations...
pill for life to compensate for reduced absorption of essential nutrients . Because patients cannot eat a large quantity of food, physicians typically recommend a diet that is relatively high in protein and low in carbohydrates and
alcoholAn alcoholic beverage is a drink that contains ethanol . Alcoholic beverages are divided into three general classes: beers, wines, and spirits....
.
Weight loss
In general, the malabsorptive procedures lead to more weight loss than the restrictive procedures. A
meta-analysisIn statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. This is normally done by identification of a common measure of effect size, which is modelled using a form of meta-regression...
from
University of California, Los AngelesThe University of California, Los Angeles is a research university located in the Westwood neighborhood of Los Angeles, California, in the United States. It was founded in 1919 and is the second-oldest general-purpose campus in the University of California system...
reports the following weight loss at 36 months:
- Biliopancreatic diversion - 53 kg
- Roux-en-Y gastric bypass (RYGB) - 41 kg
- Open - 42 kg
- Laparoscopic - 38 kg
- Adjustable gastric banding - 35 kg
- Vertical banded gastroplasty - 32 kg
Reduced mortality and morbidity
Several recent studies report decrease in mortality and severity of medical conditions after bariatric surgery.
But long term effects are not clear.
In the Swedish prospective matched controlled trial, patients with a
body mass indexThe body mass index , or Quetelet index, is a controversial statistical measurement which compares a person's weight and height. Though it does not actually measure the percentage of body fat, it may be a useful tool to estimate a healthy body weight based on how tall a person is...
(BMI) of 34 or more for men and 38 or more for women underwent various types of bariatric surgery and were followed for an average of 11 years. Surgery patients had a 23.7% reduction in mortality (5.0% vs. 6.3% control, adjusted hazard ratio 0.71). This means 75 patients must be treated to avoid one death after 11 years (
number needed to treatThe number needed to treat is an epidemiological measure used in assessing the effectiveness of a health-care intervention, typically a treatment with medication. The NNT is the number of patients who need to be treated in order to prevent one additional bad outcome...
is 77).
In a Utah retrospective
cohort studyA cohort study or panel study is a form of longitudinal study used in medicine, social science and ecology. It is one type of study design and should be compared with a cross-sectional study....
that followed patients for an average of 7 years after various types of gastric bypass, surgery patients had 0.4% mortality while control patients had 0.6% mortality. Death rates were lower in the gastric bypass patients for all diseases combined, as well as for diabetes, heart disease and cancer. Deaths from accident and suicide were 58% higher in the surgery group.
A randomized, controlled trial in Australia compared laparoscopic adjustable gastric banding ("lap banding") with non-surgical therapy in 80 moderately obese adults (BMI 30-35). At 2 years, the surgically-treated group lost more weight (21.6% of initial weight vs. 5.5%) and had statistically significant improvement in blood pressure, measures of diabetic control, and high-density lipoprotein cholesterol. Post surgical complications included 1 patient with an infected surgical site, 4 with lap band malpositioning requiring laparoscopic revision, and 1 patient with
cholecystitisCholecystitis is inflammation of the gall bladder.-Causes and pathology:Cholecystitis is often caused by cholelithiasis , with choleliths most commonly blocking the cystic duct directly. This leads to inspissation of bile, bile stasis, and secondary infection by gut organisms, predominantly E...
. In the non-surgical group, 12 patients declined or did not tolerate
orlistatOrlistat , also known as tetrahydrolipstatin, is a drug designed to treat obesity. Its primary function is preventing the absorption of fats from the human diet, thereby reducing caloric intake...
or diet restrictions, and 4 patients developed acute cholecystitis.
Bariatric surgery in older patients has also been a topic of debate, centered on concerns for safety in this population. One study of elderly patients undergoing laparoscopic bariatric surgery at Mount Sinai Medical Center, however, reported 0% conversion to open surgery, 0% 30-day mortality, 7.3% complication rate, and average hospital stay of 2.8 days.
post operative mortality from 0.1 - 2 %
Laparoscopic bariatric surgery requires a hospital stay of only one or two days. Short-term complications from laparoscopic adjustable gastric banding are reported to be lower than laparoscopic Roux-en-Y surgery, and complications from laparoscopic Roux-en-Y surgery are lower than conventional (open) Roux-en-Y surgery.
Adverse effects
Complications from weight loss surgery are frequent. A study of insurance claims of 2522 who had undergone bariatric surgery showed 21.9% complications during the initial hospital stay and a total of 40% risk of complications in the subsequent six months. This was more common in those over 40 and led to increased health care expenditure. Common problems were
gastric dumping syndromeGastric dumping syndrome, or rapid gastric emptying, happens when the upper end of the small intestine, the jejunum, expands too quickly due to the presence of hyperosmolar food from the stomach. "Early" dumping begins concurrently or immediately succeeding a meal. Symptoms of early dumping include...
in about 20% (bloatedness and diarrhoea after eating, necessitating small meals or medication), leaks at the surgical site (12%),
incisional herniaAn incisional hernia occurs in an area of weakness caused by an incompletely-healed surgical wound. Since median incisions in the abdomen are frequent for abdominal exploratory surgery, ventral incisional hernias are termed ventral hernias...
(7%),
infectionAn infection is the detrimental colonization of a host organism by a foreign species. In an infection, the infecting organism seeks to utilize the host's resources to multiply, usually at the expense of the host. The infecting organism, or pathogen, interferes with the normal functioning of the...
s (6%) and
pneumoniaPneumonia is an inflammatory illness of the lung. Frequently, it is described as lung parenchyma/alveolar inflammation and abnormal alveolar filling with fluid ....
(4%). Mortality was 0.2%. As the rate of complications appears to be reduced when the procedure is performed by an experienced surgeon, guidelines recommend that surgery is performed in dedicated or experienced units.