Obesity Surgery (journal)
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Bariatric surgery (or weight loss surgery) includes a variety of procedures performed on people who are obese. Long term weight loss through the standard of care procedures ( Roux en-Y bypass,
sleeve gastrectomy Sleeve gastrectomy is a surgical weight-loss procedure in which the stomach is reduced to about 15% of its original size, by surgical removal of a large portion of the stomach along the greater curvature. The result is a sleeve or tube like struc ...
, and biliopancreatic diversion with duodenal switch) is largely achieved by altering gut hormone levels responsible for hunger and satiety, leading to a new hormonal weight set point. Bariatric surgery is the most effective treatment causing weight loss and reducing complications of obesity. As of October 2022, the American Society of Metabolic and Bariatric Surgery (ASMBS) and International Federation for the Surgery of Obesity (IFSO) recommend bariatric surgery for adults with a
body mass index Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...
(BMI) >35, regardless of obesity-associated conditions, and recommend considering surgery for people with BMI 30.0-34.9 who have metabolic disease. This is a recent change in guidelines (October 2022), so other guideline-producing organizations and health insurance plans may take time before their guidelines are updated. Bariatric surgery can have significant health benefits in addition to weight loss, including improvement in cardiovascular risk factors, fatty liver disease, diabetes management, and reduction in mortality. Long-term studies from 2009 show the procedures result in significant long-term loss of weight, recovery from
diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
, improvement in cardiovascular risk factors, and a mortality reduction from 40% to 23%. A meta-analysis in 2021 found that bariatric surgery was associated with 59% and 30% reduction in all-cause mortality among obese adults with or without
type 2 diabetes Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, ...
, respectively. This meta-analysis also found that median life-expectancy was 9.3 years longer for obese adults with diabetes who received bariatric surgery as compared to routine (non-surgical) care, whereas the life expectancy gain was 5.1 years longer for obese adults without diabetes. A 2013 National Institute of Health symposium summarizing available evidence found a 29% mortality reduction, a 10-year remission rate of
type 2 diabetes Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, ...
of 36%, fewer cardiovascular events, and a lower rate of diabetes-related complications in a long-term, non-randomized, matched intervention 15–20 year follow-up study, the Swedish Obese Subjects Study. The symposium also found similar results from a Utah study using more modern gastric bypass techniques, though the follow-up periods of the Utah studies are only up to seven years. While randomized controlled trials of bariatric surgery exist, they are limited by short follow-up periods. The risk of death in the period following surgery is less than 1 in 1,000.


Physiology

Each type of procedure exerts its effects through at least one of three mechanisms: restricting food intake, decreasing nutrient absorption, or affecting the body's cell signaling pathways. Often, procedures affect several of these mechanisms.


Restricting food intake

This is accomplished by reducing the size of the stomach that is available to hold a meal, (for example, gastric sleeve or stomach folding, see below). Filling the stomach faster enables an individual to feel more full after a smaller meal.


Decreasing nutrient absorption

Some procedures work by reducing the amount of intestine that food passes through. For example, a Roux-en-Y Gastric Bypass connects the stomach to a more distal part of the intestine, which reduces the ability of the intestines to absorb nutrients from the food.


Affecting cell signaling pathways

While bariatric procedures may have initially been targeted at reducing intake and absorption, studies have shown additional affects on the hormones that dictate hunger (e.g. ghrelin) and satiety (leptin). This is especially important when considering the durability of weight loss compared to lifestyle changes. While diet and exercise are essential for maintaining a healthy weight and physical fitness, metabolism typically slows as the individual loses weight, a process known as Metabolic Adaptation. Thus, efforts for obese individuals to lose weight often stall, or result in weight re-gain. Bariatric surgery is thought to affect the weight "set point," leading to a more durable weight loss. This is not completely understood, but may involve the cell-signaling pathways and hunger/satiety hormones.


Medical uses

Bariatric surgery has proven to be the most effective obesity treatment option for durable weight loss. Along with this weight reduction, the procedure has significant health benefits ranging from reduced cardiovascular risk factors, remission of Type 2 Diabetes, reduced fatty liver disease, lower incidence and severity of depression syndromes, among others.


Indications

Historically, eligibility for bariatric surgery was defined as a BMI >40, or a BMI >35 with an obesity associated comorbidity—based on the 1991 NIH Consensus Statement. In the three decades that followed, obesity rates have continued to rise, laparoscopic surgical techniques have made the procedure more safe, and high-quality research studies have shown the procedure's effectiveness at improving health across a variety of conditions. Thus, in October 2022, ASMBS/IFSO put forward a revised eligibility criteria, which now includes all adult patients with BMI>35, and those with BMI >30 with metabolic disease. As of 2019, the
American Academy of Pediatrics The American Academy of Pediatrics (AAP) is an American professional association of pediatricians, headquartered in Itasca, Illinois. It maintains its Department of Federal Affairs office in Washington, D.C. Background The Academy was founded ...
has recommended bariatric surgery without age-based eligibility limits under the following indications: BMI >35 with severe comorbidity, such as
obstructive sleep apnea Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episod ...
(Apnea-Hypopnea Index >.5), Type 2 Diabetes mellitus, idiopathic intracranial hypertension,
nonalcoholic steatohepatitis Non-alcoholic fatty liver disease (NAFLD), also known as metabolic (dysfunction) associated fatty liver disease (MAFLD), is excessive fat build-up in the liver without another clear cause such as alcohol use. There are two types; non-alcoholic ...
,
Blount disease Blount's disease (or Blount disease) is a growth disorder of the tibia (shin bone) which causes the lower leg to angle inward, resembling a bowleg. It is also known as "tibia vara". Description and risk factors Blount disease is a growth disorder ...
, slipped capital femoral epiphysis, gastroesophageal reflux disease, and idiopathic hypertension or a BMI >40 kg/m2 without comorbidities. Surgery is contraindicated with a medically correctable cause of obesity, substance abuse, concurrent or planned pregnancy,
eating disorder An eating disorder is a mental disorder defined by abnormal eating behaviors that negatively affect a person's physical or mental health. Only one eating disorder can be diagnosed at a given time. Types of eating disorders include binge eating d ...
, or inability to adhere to postoperative recommendations and mandatory lifestyle changes. When counseling a patient on bariatric procedures, providers should take an interdisciplinary approach. Psychiatric screening is also critical for determining postoperative success. Patients with a body-mass index of 40 kg/m2 or greater have a 5-fold risk of depression, and half of bariatric surgery candidates are depressed. Some people with disordered eating may not be able to follow post-operative dietary guidelines.


Weight loss

In adults, the malabsorptive procedures lead to more weight loss than the restrictive procedures; however, they have a higher risk profile. A 2005
meta-analysis A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting me ...
from
University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...
, reported the following weight loss at 36 months: Biliopancreatic diversion — 117 Lbs / 53 kg, Roux-en-Y gastric bypass (RYGB) — 90 Lbs / 41 kg, Open — 95 Lbs/ 43 kg, Laparoscopic — 84 Lbs / 38 kg, Vertical banded gastroplasty — 71 Lbs / 32 kg. In children and teens, evidence for the effectivenss of bariatric surgery is more context-specific. A 2017 meta-analysis found bariatric surgery to be effective for weight loss in adolescents 36 months after the intervention and that additional data was needed to determine whether it is also effective for long-term weight loss in adolescents. According to the
Canadian Agency for Drugs and Technologies in Health The Canadian Agency for Drugs and Technologies in Health, or CADTH, is a Canadian national organisation that provides research and analysis to healthcare decision-makers. The organisation was established in 1989 by the country's federal governme ...
, the comparative evidence base for bariatric surgery in adolescents and young adults was as of 2016 "...limited to a few studies that were narrow in scope and with relatively small sample sizes."


Type 2 Diabetes Mellitus

Type 2 Diabetes Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, ...
is characterized by the body's resistance to the hormone
insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism o ...
, which results in high blood sugars and a range of complications including increased risk of heart attack, retinopathy, kidney failure, and peripheral neuropathy. Recent studies have shown that patients who have undergone bariatric surgery can often maintain their blood sugars within acceptable levels while discontinuing their diabetes medications. This may essentially amount to a 'cure' for diabetes. Prior to the updated guidelines ASMBS/IFSO, international diabetes organizations had recommended considering bariatric surgery in people with a BMI over 30 who have type 2 diabetes and poorly controlled
hyperglycemia Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200  mg/dL), but symptoms may not start to become noticeable until even ...
.


Reduced mortality and morbidity

A meta-analysis of 174,772 participants published in
The Lancet ''The Lancet'' is a weekly peer-reviewed general medical journal and one of the oldest of its kind. It is also the world's highest-impact academic journal. It was founded in England in 1823. The journal publishes original research articles, ...
in 2021 found that bariatric surgery was associated with 59% and 30% reduction in all-cause mortality among obese adults with or without
type 2 diabetes Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, ...
respectively. This meta-analysis also found that median life-expectancy was 9.3 years longer for obese adults with diabetes who received bariatric surgery as compared to routine (non-surgical) care, whereas the life expectancy gain was 5.1 years longer for obese adults without diabetes. Bariatric surgery in older patients has also been a topic of debate, centered on concerns for safety in this population; the relative benefits and risks in this population is not known.


Fertility and pregnancy

The position of the American Society for Metabolic and Bariatric Surgery as of 2017 was that it was not clearly understood whether medical weight-loss treatments or bariatric surgery had an effect responsiveness to subsequent treatments for infertility in both men and women. Bariatric surgery reduces the risk of
gestational diabetes Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and of ...
and
hypertensive disorders of pregnancy Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...
in women who later become pregnant but increases the risk of
preterm birth Preterm birth, also known as premature birth, is the Childbirth, birth of a baby at fewer than 37 weeks Gestational age (obstetrics), gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 we ...
.


Mental Health

Among the patients who seek bariatric surgery, pre-operative mental health struggles are common. Some studies have suggested that psychological health can improve after bariatric surgery, due in part to improved body image, self-esteem, and change in self-concept—these findings were also present in pediatric populations. Bariatric surgery has consistently been associated with postoperative decreases in depressive symptoms and reduced severity of symptoms. Importantly, the surgery may not affect everyone the same way, and there are potential adverse effects outlined in the next section.


Adverse effects

Weight loss surgery in adults is associated with relatively large risks and complications, compared to other treatments for obesity. The likelihood of major complications from weight-loss surgery is 4%. "Sleeve gastrectomy had the lowest complication and reoperation rates of the three (main weight-loss surgery) procedures.....The percentage of procedures requiring reoperations due to complications was 15.3 percent for the gastric band, 7.7 percent for gastric bypass and 1.5 percent for sleeve gastrectomy," according to a 2012 study by the American Society for Metabolic and Bariatric Surgery. Over a 10-year study while using a common data model to allow for comparisons, 8.94% of patients who received a sleeve gastrectomy required some form of reoperation within 5 years compared to 12.27% of patients who received a Roux-en-Y gastric bypass. Both of the effects were fewer than those reported with adjustable gastric banding. As the rate of complications appears to be reduced when the procedure is performed by an experienced surgeon, guidelines recommend that surgery be performed in dedicated or experienced units. It has been observed that the rate of leaks was greater in low volume centres whereas high volume centres showed a lesser leak rate. Leak rates have now globally decreased to a mean of 1-5%.


Postoperative Complications

Laparoscopic Laparoscopy () is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.Medli ...
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. Risks of Roux-en-Y Gastric Bypass include Anastomotic Stenosis (narrowing of the intestine where the two segments are rejoined), Marginal ulcers (ulcers near the rejoined segment), internal hernia, small bowel obstruction, kidney stones, and gall stones. Sleeve Gastrectomy also carries a small risk of stenosis, staple line leak, and gastro-esophageal reflux disease (also known as GERD, or heartburn). In addition to procedure-specific risks, patients also face risks to surgery in general. Pulmonary embolism is another common adverse complication of bariatric surgery. Pulmonary embolism occurs due as a result of deep vein thrombosis, in which blood clots form in the deep veins of the extremities, usually the legs. If not treated, the clot can travel to the heart and then to the lung. This adverse effect is simply prevented by heparin and
LMWH Low-molecular-weight heparin (LMWH) is a class of anticoagulant medications. They are used in the prevention of blood clots and treatment of venous thromboembolism (deep vein thrombosis and pulmonary embolism) and in the treatment of myocardia ...
, which are both blood thinning medications.


Dumping Syndrome

Dumping syndrome is a condition characterized by quick emptying of the stomach and frequent bowel movements. It is more common following RYGB than SG, and can typically be treated through dietary modification.


Metabolic Bone Disease

Metabolic bone disease manifesting as osteopenia and secondary
hyperparathyroidism Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. This occurs from a disorder either within the parathyroid glands (primary hyperparathyroidism) or as response to external stimuli (secondary hyperparathyroidism). ...
have been reported after Roux-en-Y gastric bypass surgery due to reduced calcium absorption. The highest concentration of calcium transporters is in the duodenum. Since the ingested food will not pass through the duodenum after a bypass procedure, calcium levels in the blood may decrease, causing secondary hyperparathyroidism, increase in bone turnover, and a decrease in bone mass. Increased risk of fracture has also been linked to bariatric surgery.


Cholelithiasis (Gallstones)

Rapid weight loss after obesity surgery can contribute to the development of gallstones by increasing the lithogenicity of bile. Estimates for prevalence of symptomatic cholecystitis after Roux-En-Y Gastric Bypass range from 3-13%. Cholelithiasis can be managed with a removal of the gallbladder (
Cholecystectomy Cholecystectomy is the surgical removal of the gallbladder. Cholecystectomy is a common treatment of symptomatic gallstones and other gallbladder conditions. In 2011, cholecystectomy was the eighth most common operating room procedure performed i ...
).


Renal Effects

Adverse effects on the kidneys have been studied. Hyperoxaluria that can potentially lead to oxalate nephropathy and irreversible renal failure is the most significant abnormality seen on urine chemistry studies.
Rhabdomyolysis Rhabdomyolysis (also called rhabdo) is a condition in which damaged skeletal muscle breaks down rapidly. Symptoms may include muscle pains, weakness, vomiting, and confusion. There may be tea-colored urine or an irregular heartbeat. Some of th ...
leading to acute kidney injury, and impaired renal handling of acid and base has been reported after bypass surgery. Additionally,
Nephrolithiasis Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...
(kidney stones) are common after Roux-En-Y Gastric Bypass, with estimates of prevalence ranging from 7-11%.


Nutritional Deficiencies

Deficiencies of micronutrients like iron, vitamin B12, fat soluble vitamins, thiamine, and folate are especially common after malabsorptive bariatric procedures. Seizures due to hyperinsulinemic hypoglycemia have been reported. Inappropriate insulin secretion secondary to islet cell hyperplasia, called pancreatic nesidioblastosis, might explain this syndrome.


Mental Health

Though many benefits to mental health are described above, there are several potential adverse effects that should be discussed. Alcohol problems have been reported to be more common in patients who have undergone gastric bypass surgery. Of note, patients who receive an RYGB may reach a higher peak alcohol concentration more quickly, due to changes in their metabolism. In addition, Self-harm behaviors and suicide appear to be increased in people with mental health issues in the five years after bariatric surgery had been done.


Types

Bariatric procedures can be grouped in three main categories: blocking (reduce the absorption of nutrients), restricting (decrease the size of the gut and therefore the amount of food that can pass through), and mixed which are understood to work by altering gut hormone levels responsible for hunger and satiety. However, this distinction might be less clear-cut than it may seem. For instance, while Sleeve Gastrectomy (discussed below) was initially thought to work simply by reducing the size of the stomach, research has begun to elucidate changes in gut hormone signaling as well. The two most frequently performed procedures are Sleeve Gastrectomy and Roux-en-Y Gastric Bypass (also galled gastric bypass), with Sleeve Gastrectomy accounting for more than half of all procedures since 2014.


Most Common


Sleeve gastrectomy

Sleeve gastrectomy, or gastric sleeve, is a surgical
weight-loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other conn ...
procedure in which the stomach is reduced to about 15% of its original size, by the surgical removal of a large portion of the stomach, following the major curve. The open edges are then attached together (typically with
surgical staple Surgical staples are specialized staples used in surgery in place of sutures to close skin wounds or connect or remove parts of the bowels or lungs. The use of staples over sutures reduces the local inflammatory response, width of the wound, a ...
s, sutures, or both) to leave the stomach shaped more like a tube, or a sleeve, with a banana shape. While this procedure was initially thought to work only by reducing the size of the stomach, recent research has also shown that there are changes in gut signaling hormones. The procedure is performed
laparoscopic Laparoscopy () is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.Medli ...
ally and is not reversible. It has been found to produce a weight loss comparable to that of Roux-en-Y gastric bypass. While it is not as effective at treating GERD or Type 2 Diabetes as RYGB, it has less risk of side effects like ulcers or intestinal strictures (narrowing of the gut).


Roux-en-Y Gastric Bypass Surgery (RYGB)

Main article: Gastric bypass surgery The Roux-en-Y gastric bypass is designed to alter the gut hormones that control hunger and satiety. While the complete hormonal mechanisms are still being understood, it is now widely accepted that this is a hormonal procedure in addition to restriction and malabsorption properties. Gastric bypass is a permanent procedure that helps patients reset hunger and satiety by altering stomach and small intestine handle the food that is eaten to achieve and maintain weight loss goals. After the surgery, the stomach will be smaller and there will be an increase in baseline satiety hormones, to help the patient will feel full with less food. The gastric bypass had been the most commonly performed operation for weight loss in the United States, and approximately 140,000 gastric bypass procedures were performed in 2005. Its market share has decreased, and since 2013, Sleeve Gastrectomy has overtaken RYGB as the most common bariatric procedure. A factor in the success of any bariatric surgery is strict post-surgical adherence to a healthy pattern of eating. One common side effect of bariatric surgery that is commonly reported with RYGB is Dumping Syndrome, in which food moves too quickly from the stomach to the small intestine. This can usually be treated through dietary changes.


Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

Main Article: biliopancreatic diversion with duodenal switch A slightly less common bariatric procedure, accounting for less than 1% of all bariatric procedures in 2016. The part of the stomach along its greater curve is resected and the remaining 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 intestine The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...
. The duodenum and the upper part of the small intestine are reattached to the rest at about 75–100 cm from the colon. citation needed''">ikipedia:Citation_needed.html" ;"title="'Wikipedia:Citation needed">citation needed''/sup>. Like the Roux en Y Bypass, it is now understood that its results are largely due to a significant alteration in gut hormones that control hunger and satiety, in addition to its restriction and malabsorption properties. The addition of the sleeve gastrectomy, causes further gut hormone set- point alterations by reducing levels of the hunger hormone, Ghrelin. Compared to the Sleeve Gastrectomy and Rou-en-Y Gastric Bypass, BPD/DS produces the best results in terms of durable weight loss and resolution of Type 2 Diabetes.


Other procedures


Vertical banded gastroplasty

In the Vertical banded gastroplasty surgery">vertical banded gastroplasty, 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.


Stomach folding

Basically, the procedure can best be understood as a version of the more popular gastric sleeve or gastrectomy surgery where a sleeve is created by suturing rather than removing stomach tissue thus preserving its natural nutrient absorption capabilities. Gastric plication significantly reduces the volume of the patient's stomach, so smaller amounts of food provide a feeling of satiety. The procedure is producing some significant results that were published in a recent study in ''Bariatric Times'' and are based on post-operative outcomes for 66 patients (44 female) who had the gastric sleeve plication procedure between January 2007 and March 2010. Mean patient age was 34, with a mean BMI of 35. Follow-up visits for the assessment of safety and weight loss were scheduled at regular intervals in the postoperative period. No major complications were reported among the 66 patients. Weight loss outcomes are comparable to gastric bypass. The study describes gastric sleeve plication (also referred to as
gastric imbrication The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach is ...
or
laparoscopic greater curvature plication Laparoscopy () is an operation performed in the abdomen or human pelvis, pelvis using small Surgical incision, incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few ...
) as a restrictive technique that eliminates the complications associated with adjustable
gastric banding A laparoscopic adjustable gastric band, commonly called a lap-band, A band, or LAGB, is an inflatable silicone device placed around the top portion of the stomach to treat obesity, intended to decrease food consumption. Adjustable gastric band ...
and vertical
sleeve gastrectomy Sleeve gastrectomy is a surgical weight-loss procedure in which the stomach is reduced to about 15% of its original size, by surgical removal of a large portion of the stomach along the greater curvature. The result is a sleeve or tube like struc ...
—it does this by creating restriction without the use of implants and without gastric resection (cutting) and staples.


Implants and Devices


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 band". Weight loss is predominantly due to the restriction of nutrient intake that is created by the small gastric pouch and the narrow outlet. It is considered somewhat of a safe surgical procedure, with a mortality rate of 0.05%.


Intragastric balloon

Intragastric balloon involves placing a deflated balloon into the stomach, and then filling it to decrease the amount of gastric space. The balloon can be left in the stomach for a maximum of 6 months and results in an average weight loss of 5–9 BMI over half a year. The intragastric balloon is approved in Australia, Canada, Mexico, India, United States (received FDA approval in 2015) and several European and South American countries. The intragastric balloon may be used prior to another bariatric surgery in order to assist the patient to reach a weight which is suitable for surgery, further it can also be used on several occasions if necessary. There are three cost categories for the intragastric balloon: pre-operative (e.g. professional fees, lab work and testing), the procedure itself (e.g. surgeon, surgical assistant, anesthesia and hospital fees) and post-operative (e.g. follow-up physician office visits, vitamins and supplements). Quoted costs for the intragastric balloon are surgeon-specific and vary by region. Average quoted costs by region are as follows (provided in United States Dollars for comparison): Australia: US$4,178; Canada: US$8,250; Mexico: US$5,800; United Kingdom: US$6,195; United States: US$8,150.


Endoluminal sleeve

This is a flexible tube inserted, through the mouth and stomach, into the upper small intestine. The purpose is to block absorption of certain foods/calories. It does not involve actual cutting and so is designed to lower risks from infection etc. however the results were not conclusive and the device had issues with migration and slipping. A study recently done in the Netherlands found a decrease of 5.5 BMI points in 3 months with an endoluminal sleeve.


Implantable gastric stimulation

This procedure where a device similar to a heart pacemaker that 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 system 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.


Historical Procedures (rarely performed)


Biliopancreatic diversion

This operation is termed ''biliopancreatic diversion'' (BPD) or the ''Scopinaro procedure''. The original form of this procedure is now rarely performed and has been replaced with a modification known as biliopancreatic diversion with duodenal switch (BPD/DS), or simply
duodenal switch The duodenal switch (DS) procedure, gastric reduction duodenal switch (GRDS), is a weight loss surgery procedure that is composed of a restrictive and a malabsorptive aspect. The restrictive portion of the surgery involves removing approximate ...
(DS). Part of the stomach is resected, creating a smaller stomach (however the patient can eat a free diet as there is no restrictive component). The
distal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
part of the
small intestine The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...
is then connected to the pouch, bypassing the
duodenum The 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 m ...
and jejunum. In around 2% of patients there is severe malabsorption and nutritional deficiency that requires restoration of the normal absorption. The malabsorptive effect of BPD is so potent that, as in most restrictive procedures, those who undergo the procedure must take
vitamin A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an Nutrient#Essential nutrients, essential micronutrient that an organism needs in small quantities for the proper functioning of its ...
and
dietary mineral In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon ...
s above and beyond that of the normal population. Without these supplements, there is risk of serious deficiency diseases such as
anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
and
osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone ...
. Because gallstones are a common complication of the rapid weight loss following any type of bariatric surgery, some surgeons remove the gallbladder as a preventive measure during BPD. Others prefer to prescribe
medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...
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. It was a surgical weight-loss procedure performed for the relief of morbid obesity from the 1950s through the 1970s in which all but 30 cm (12 in) to 45 cm (18 in) of the
small bowel The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pa ...
was detached and set to the side.


Post-Procedure Follow-up

In many institutions, patients are followed closely both before and after a procedure. The care team may also include people in a variety of disciplines, including social work, dietitians, and medical weight management specialists. Follow up post-op is typically focused on helping avoid complications, and tracking patients' progress toward their weight goals.


Dietary Recommendations

Diet restrictions after recovery from surgery depend in part on the type of surgery. In general, 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 drinks and gelatin desserts. This diet is continued until the gastrointestinal tract begins to recover. The next stage provides a blended or pureed sugar-free diet for at least two weeks. This may consist of high protein, liquid or soft foods such as protein shakes, soft meats, and dairy products. Foods high in carbohydrates are usually avoided when possible during the initial weight loss period. Post-surgery, overeating is curbed because exceeding the capacity of the stomach causes
nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...
and
vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...
. In the long term, many patients will need to take a daily
multivitamin A multivitamin is a preparation intended to serve as a dietary supplement with vitamins, dietary minerals, and other nutritional elements. Such preparations are available in the form of tablets, capsules, pastilles, powders, liquids, or injectable ...
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 fats and
alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...
.


Fluid recommendations

It is very common, within the first-month post-surgery, for a patient to undergo volume depletion and dehydration. Patients have difficulty drinking the appropriate amount of fluids as they adapt to their new gastric volume. Additionally, limitations on oral fluid intake, reduced calorie intake, and a higher incidence of vomiting and diarrhea all contribute to dehydration.


Family Planning

In general, patients are advised to avoid pregnancy for 12–24 months after a bariatric surgery. This waiting period is intended to reduce the possibility of Intrauterine Growth Restriction or nutrient deficiency, since the bariatric surgery patient will likely undergo significant weight loss and changes in metabolism. In the long run, however, the rates of many adverse maternal and fetal outcomes are reduced for obese mothers following bariatric surgery.


Cosmetic body contouring

After a person successfully loses weight following bariatric surgery, they are usually left with excess skin. These can be addressed in a series of
plastic surgery Plastic surgery is a surgical specialty involving the restoration, reconstruction or alteration of the human body. It can be divided into two main categories: reconstructive surgery and cosmetic surgery. Reconstructive surgery includes craniofa ...
procedures sometimes called body contouring in which the skin flaps are removed. Targeted areas include the arms, buttocks and thighs, abdomen, and breasts. These procedures are taken slowly, step by step, and from beginning to end often takes three years.


Economic Implications

The cost of healthcare in the United States is increasing, and obesity rates are likely to be playing a role. Per the CDC, approximately 41.9% of US adults are obese (as measured from 2017-2020), a rate that has increased significantly from a level of 30.5% in 1999-2000. Obesity-related illnesses account for 14.3% of US healthcare spending, and also result in significant losses to the economy through decreased productivity. Bariatric surgery is expensive, with average cost estimates ranging from $11,500 to $26,000, however, this cost is estimated to be recovered within 2–4 years due to decreased healthcare spending, gains in quality-adjusted life-years (QALYs) and increased productivity. Cohort modeling has found that Bariatric Surgery results in a net QALY gain of 4.2, and is cost-saving from a societal perspective. Even by the previous BMI criteria, a study had found that more than 32 million people may have been eligible for bariatric surgery in 2016—nearly triple the 1993 amount. Importantly, only ~1% of eligible patients receives bariatric surgery.


Considerations in adolescent patients

As
childhood obesity Childhood obesity is a condition where excess body fat negatively affects a child's health or well-being. As methods to determine body fat directly are difficult, the diagnosis of obesity is often based on BMI. Due to the rising prevalence of ...
has more than doubled over recent years and more than tripled in adolescents (according to the
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
), bariatric surgery for youth has become increasingly common across the various types of procedures. Some worry that a decline in life expectancy might occur from the increasing levels of obesity, so providing youth with proper care may help prevent the serious medical complications caused by obesity and its related diseases. Difficulties and ethical issues arise when making decisions related to obesity treatments for those that are too young or otherwise unable to give consent without adult guidance. Children and adolescents are still developing, both physically and mentally. This makes it difficult for them to make an informed decision and give consent to move forward with a treatment. These patients may also be experiencing severe depression or other psychological disorders related to their obesity that make understanding the information very difficult.


History

Open weight loss surgery began slowly in the 1950s with the intestinal bypass. It involved
anastomosis An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection m ...
of the upper and lower intestine, which bypasses a large amount of the absorptive circuit, which caused weight loss purely by the malabsorption of food. Later Drs. J. Howard Payne, Lorent T. DeWind and Robert R. Commons developed in 1963 the Jejuno-colic Shunt, which connected the upper small intestine to the colon. The laboratory research leading to gastric bypass did not begin until 1965 when Dr. Edward E. Mason (b. 1920) and Dr. Chikashi Ito (1930–2013) at the
University of Iowa The University of Iowa (UI, U of I, UIowa, or simply Iowa) is a public university, public research university in Iowa City, Iowa, United States. Founded in 1847, it is the oldest and largest university in the state. The University of Iowa is org ...
developed the original gastric bypass for weight reduction which led to fewer complications than the intestinal bypass and for this reason Mason is known as the "father of obesity surgery".


See also

*
Revision weight loss surgery Revision weight loss surgery is a surgical procedure that is performed on patients who have already undergone a form of bariatric surgery, and have either had complications from such surgery or have not achieved significant weight loss results from ...
*
Endoscopic sleeve gastroplasty In medicine, endoscopic sleeve gastroplasty (ESG) is a minimally-invasive, non-surgical (incisionless), endoscopic weight loss procedure that is part of the field of endoscopic bariatric therapies. To perform ESG, a physician sutures a patient’s ...


References


External links

* {{DEFAULTSORT:Bariatric surgery
Surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
Digestive system surgery Surgical specialties