Bariatric surgery

Only intervention that consistently helps obese patients to achieve significant and sustained weight loss and improves comorbid conditions.

Indicated for patients with a BMI greater than 40 kg/meter squared or with a BMI greater than 35 kg/m² in the presence of weight related complications.

About 7.7% of the US population has a BMI of 40 kg/m² or greater and that makes more than 25 million people medically appropriate for consideration of bariatric surgery as therapy for severe obesity.

In 2017 228,000 bariatric procedures were performed in the US.

Approximately 80% of patients who undergo this surgery are female.


Candidacy is complex and is assessed by medical practitioners including an endocrinologist, psychologist, and bariatric surgeon.

Estimated 200,000 bariatric surgeries are performed annually in the US.

About 1% of eligible patients undergo such surgery each year.

Utilization in African Americans and Hispanics of this procedure is less than 1%.

Reduces caloric intake by modifying the gastrointestinal tract anatomy.

Bariatric surgery reduces the long-term incidence to diabetes by 80% in the Swedish Obese Subject study.

Associated with a lowe risk of incident major macrovascular events in diabetic patients.

Surgery classified as either restrictive or malabsorptive.

Bariatric surgery has evolved into four major procedures-biliopancreatic diversion, Roux-en-Y gastric bypass, adjustable gastric banding, and sleeve gastrectomy.

The jejunobypass, vertical banded gastroplasty, laparoscopic adjustable gastric banding have largely been abandoned. 

The long term evidence for the Roux-en-Y gastric bypass procedure has substantially improved.

A study reported the median time to maximum  weight loss was two years after Roux-en-Y gastric bypass, and the maximum weight loss was 37.4% of pre-surgery weight.

Weight regain is greatest during the first year after reaching nadir weight, with a median regain of 9.5% of the maximum weight loss: Add five years the median regain of the maximum weight loss was 26.8%.

Restrictive procedures limit intake by creating a small gastric reservoir with narrowed outlet to impair emptying.

In a study involving 25 hospitals  and 62 surgeons in the state of Michigan, involving the short-term morbidity of 15,275 patients that underwent one of three common bariatric procedures between 2006-2009: 7.3% of patients had perioperative complications most of which were wound problems and other minor complications (Birkmeyer NJO et al).

Sleeve gastrectomy is now the most commonly performed bariatric procedure.

In the above study the most serious complications followed gastric bypass surgery (3.6%), followed by sleeve gastrectomy (2.2%) and laparoscopic adjustable gastric band  procedures (0.9%),  and mortality occurred in .04% of laparoscopic adjustable gastric band procedures, zero cases of sleeved gastrectomy and 0.14% of gastric bypass patients.

In the above study approximately 2.5% of patients had more serious complications and overall mortality occurring in 0.12% of patients.

Malabsorptive procedures bypass portions of the small intestine where nutrient absorption usually occurs.

Patients who undergo bariatric surgery often have pre-existing nutritional deficiencies from insufficient intake of micro nutrients, and common deficiencies include: thiamine, folate, B12, iron, vitamin D, calcium, and fat soluble vitamins.

Patients who undergo go bariatric surgery are at risk for several nutritional deficiencies postoperatively: vitamin C, thiamine, vitamin B6, riboflavin, vitamin A, vitamin D, and vitamin B 12.

Restrictive procedures include gastric stapling, gastric banding or a combination of these approaches.

Currently vertical gastric partitioning with creation of the gastric pouch with proximal bypass into a Jejunal loop is the reference standard.

Inflatable bands placed laparoscopically are accepted methods to restrict the size of the patient’s stomach and restrict oral intake.

Partial gastric resection with distal diversion of biliopancreatic secretions relative to orally ingested nutrients has also proved to be efficacious management.

The above procedures such as Roux-en-Y gastric bypass, laparoscopic gastric banding, and biliopancreatic diversion have low mortality and low rates of complications similar to other surgical procedures (The Longitudinal Assessment of Bariatric Surgery Consortium).

Adjustable gastric banding consists of wrapping a synthetic inflatable band around the stomach creating a small pouch with a narrow outlet.

Adjustable gastric banding includes the insertion of a subcutaneous reservoir to adjust gastric restriction by use of saline injections.

Adjustable gastric binding can be performed laparoscopically.

The gastric band can be removed as an outpatient without the use of anesthesia.

A vertical restrictive sleeve gastrectomy can leave the gastric body as a narrow tube of stomach and is another restrictive procedure that can be done.

Gastric sleeve surgery, or vertical sleeve gastrectomy, is a type of bariatric surgery.

Multiply referred to medically as gastric sleeve resection, sleeve gastrectomy, tube gastrectomy or laparoscopic sleeve gastrectomy.

During this procedure about 85 percent of the stomach is removed, leaving the stomach in the shape of a tube or sleeve.

This operation is performed laparoscopically, and the tube-shaped stomach that is left is sealed closed with staples.

In some cases, gastric sleeve surgery may be followed by a gastric bypass surgery or duodenal switch surgery after a person has lost a significant amount of weight making the second procedure less risky than it would have been had it been the first and only procedure.

The indications for the sleeve are the same as other covered procedures such as gastric bypass or adjustable gastric banding.

Requirements for the procedure are a body mass index (BMI) greater than 40, the equivalent of being about 100 pounds overweight for men and 80 pounds overweight for women.

People with BMIs between 35 and 39 may also be candidates for this surgery if they have obesity-related illnesses, or in those who can’t return as often for the follow-up visits required by gastric banding procedures.

It is a non-reversible procedure, performed under general anesthesia and takes about one to two hours.

Most people who have gastric sleeve surgery lose 50 to 80 percent of their excess body weight over the first six months to one year after surgery, and show improvement in diabetes, hypertension, hyperlipidemia, and sleep apnea.

Complications include: bleeding, gastrointestinal symptoms, nutritional abnormalities, electrolyte abnornmalities, and stomac stenosis in 10-17% of patients.

Medical improvements are comparable with those seen after other weight loss surgeries.

Risks and complications of gastric sleeve surgery include: sleeve leaking and secondary infection, thromboembolism and regaining of weight.

Potential complications include gastrointestinal reflux disease or dumping syndrome.

There is no bypass of the small intestines with the gastric sleeve, so all nutrients are absorbed.

In patients over the age of 65 years there is nearly a 3-fold increase in risk of mortality.

Absolute mortality for patients over the age of 65 years is 4.8% at 30 days more than twice the risk of coronary artery revascularization (about 2%) or hip replacement (about 1%).

Postoperative mortality rates are 2-3 times higher in men than women.

Risk of death over time is 35% lower than among extremely obese individuals that do not undergo bariatric surgery (Adams TD).

Swedish Obese Subjects study of bariatric surgery demonstrated long term weight loss and decreased overall mortality.

Roux en Y gastric bypass surgery effective means of reversing or controlling metabolic syndrome in patients eligible for this surgery.

Gastric bypass involves both gastric restriction and malabsorption.

Bypass surgery involves the connection of the jejunum to the proximal stomach, bypassing most of the distal stomach and the proximal portion of the small intestine and gastric restriction is induced by the smaller gastric pouch and malabsorption relates to the length of the bypass limb.

Gastric bypass may alter the secretion of gastrointestinal hormones such as ghrelin, peptide YY and glucagon like peptide which may reduce appetite and food intake and help facilitate weight loss.

5-10% have neurologic complications caused by nutritional deficiencies of iron, vitamin B12, vitamin B1 and folate, niacin, hypokalemia, hypophosphatemia, hypomagnesemia and thiamine deficiency.

Following such surgery patients need to adapt their diet to the smaller stomach volume, and if consumption exceeds the capacity of the gastric pouch they will experience a domino discomfort, nausea, vomiting, and many experience gas or diarrhea induced by fat intake.

In obese patients with type 2 DM 12 months of medical therapy plus bariatric surgery achieves greater glycemic control in significantly more patients than does medical management alone (Schauer PR et al).

In the above study of obese patients with poorly controlled diabetes who underwent either gastrric bypass orsleeve gastrectomy combined with medical therapy were significantly more likely to achieve hemoglobin A-1 C. levels of 6% or less one year after randomization then were patients receiving medical therapy alone.

After 7 to 12 years of follow up, individual is originally randomized to undergo bariatric surgery compared with medical/lifestyle intervention had superior glycemic control with less diabetes medication use, and higher rates of diabetes remission (Courcoulas AP).

Among obese patients with type two diabetes bariatric surgery with two years of low-level lifestyle interventions results in more disease remission then lifestyle intervention alone (Arterburn D et al).

Evidence exists that bariatric surgery is more effective than medical or lifestyle interventions for weight loss and diabetes remission.

In a recent analysis of severely obese patients with diabetes, the adjusted probability of initial remission was 12-24 fold greater fool for patients treated with bariatric surgery than for the patients who received usual medical care alone(Arteburn DE et al).

Despite excessive caloric intake, patience with obesity have high rates of micronutrient deficiencies before surgery and without proper supplementation many patients who have undergone bariatric procedures develop new deficiencies, even years after the operation.

Patients may develop micronutrient deficiency after gastric bypass surgery.

After gastric bypass surgery deficiencies of B12, calcium and iron are related to the altered surgical anatomy, but also decreased nutrient intake after surgery and rapid weight loss.

Patients who have undergone gastric bypass surgery are advised to take vitamin supplementation for life, containing  iron, thiamine elemental calcium, vitamin D, and vitamin B 12.

All studies indicate surgical intervention is superior to control patients in regard to weight gain, percentage of weight loss, and adverse events.

Most studies suggest that gastric bypass produces greater degree of weight loss, about twice that of gastric banding.

With both types of procedures, weight loss will eventually plateau, and some weight gain may occur over time.

A sizable number of patients with gastric banding will not achieve significant weight loss.

Most patients reach the maximal weight loss 12-24 months after bariatric surgery, which will be approximately 1/3 of their initial total body weight.

Some patients regain weight, defined as regaining approximately 15% of the total weight loss after the surgery, and this can occur up to 50% of patients within five years of the initial bariatric procedure.

Lifestyle counseling is the mainstay of treatment for mild and moderate weight gain have to bariatric surgery.

Because of the significantly reduced gastric capabilities, patients should eat three meals and up to two snacks per day, with a diet balanced including 80 to 100 g of protein to prevent protein deficiency.

In a retrospective study mortality was examined for 850 veterans who had bariatric surgery: among patients who had bariatric surgery, the one, two, and six-year crude mortality rates were respectively 1.5%, 2.2%, and 6.8% compared with 2.2%, 4.6%, and 15.2% for non-surgical controls (Maciejewsk ML et al).

Associated with reduced number of cardiovascular deaths and lower incidence of cardiovascular events in obese patients (Sjostrom L et al).

Bariatric surgery is associated with substantial improvement in macrovascular disease.

Bariatric surgery is associated with marked reduction in the incidence of diabetes, cardiovascular disease and mortality and in women specifically reduces the incidence of cancer.


Successful weight loss withbariatric surgery substantially reduces the risk of cancers related to obesity.


Bariatric surgery have shown substantial improvements in liver histology and NAFLD activity score, including decreased prevalence of NASH.

Among patients with NASH and obesity, bariatric surgery compared with non-surgical management was associated with significant lower risk of major adverse liver outcomes and major adverse cardiovascular events (Amiinian A).

Among obese individuals with uncontrolled type two diabetes, three years of intensive medical therapy plus bariatric surgery resulted in better glycemic control in significantly more patients than medical therapy alone (STAMPEDE Investigators).

For obstructive sleep apnea greater weight loss provided by surgical bypass did not translate into better effect compared to conventional weight loss therapy: Bariatric surgery did not result in statistical greater reduction in apnea-hypopnea index (AHI) of 20 events/hour or more (Dixon JB et all).

The prevalence of alcohol use disorders was greater in the second year postoperative, and was associated with male sex, younger age, numerous preoperative variables in patients undergoing a Roux-en-Y gastric bypass procedure (king WC et al).

Among patients with obesity, bariatric surgery is associated with a longer life expectancy than usual obesity care.

Following bariatric surgery, an annual assessment includes weight trend, vitamin/minimal supplementation, exercise.  improvements of comorbidity, and yearly laboratory evaluation with a CBC, metabolic panel, vitamin B1 level, hemoglobin A-1 C, TSH, lipid evaluation, folate, iron studies, vitamin D level.

Among adults with obesity bariatric surgery compared with no surgery was associated with significant lower  incidence of obesity associated cancer and cancer related mortality.


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