BARIATRIC SURGERY

Bariatric surgery, also known as weight loss surgery, refers to the various surgical procedures performed to treat obesity by modification of the gastrointestinal tract to reduce nutrient intake and/or absorption. The term does not include procedures for surgical removal of body fat such as liposuction or abdominoplasty.

Background

For individuals who have been unable to achieve significant weight loss through diet modifications and exercise programs alone, bariatric surgery may help to attain a more healthy body weight. There are a number of surgical options available to treat obesity, each with their advantages and pitfalls. In general, bariatric surgery is successful in producing (often substantial) weight loss, though one must consider operative risk (including mortality) and side effects before making the decision to pursue this treatment option. Usually, these procedures can be carried out safely.

Indications

A clinical practice guideline by the American College of Physicians concluded: "Surgery should be considered as a treatment option for patients with a BMI of 40 kg/m 2 or greater who instituted but failed an adequate exercise and diet 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, gall bladder disease, and malabsorption." "Patients should be referred to high-volume centers with surgeons experienced in bariatric surgery."

Classification of surgical procedures

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 Switch, also known as the BPD/DS. Part of the stomach 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 intestine is then connected to the pouch, bypassing the duodenum and jejunum. This results in around 2% of patients severe malabsorption and nutritional deficiency that requires restoration on the normal absorption.

The malabsorptive element of BPD is so potent that those who undergo the procedure must take vitamin and mineral supplements above and beyond that of the normal population. Those that do not run the risk of deficiency diseases such as anemia and osteoporosis. Because gallstones are a common complication of rapid weight loss following any type of weight loss surgery, some surgeons may remove the gall bladder as a preventative measure during BPD. Others prefer to prescribe medication 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.

Diagram of a Biliopancreatic diversion.

Jejuno-ileal bypass

Jejuno-ileal (JI) bypass is an obsolete bariatric surgery procedure. The term "jejuno-ileal" refers to two of the three parts of the small intestine. The jejunum is the very long middle portion of the small intestine, and the ileum is the shorter part at the end that empties into the large intestine. JI bypass was performed by dividing the proximal jejunum and then plugging the top end of the jejunum into the ileum, much further down the small intestine. After the procedure, food would move from the stomach to the upper small intestine, then directly into the ileum, bypassing all of the absorptive areas of the jejunum. Thus, patients would eat a normal meal but would absorb only a small fraction of the calories it contained.

This procedure is no longer performed for two reasons. First, patients with no jejunum cannot effectively absorb some vitamins, especially vitamin B complex and vitamin C. This leads to severe malnutrition and liver failure. The second problem also arose from the bypassed jejunum, which emptied normally downstream into the ileum but had no 'upstream' connection and hence no inflow of food or liquids from the stomach. The flow of liquid through the intestine is necessary to cleanse it; with no liquid flow, bacteria from the large intestine are free to grow and colonize the small intestine, all the way up to the blind end of the jejunum. This leads to sepsis by bacterial translocation, so effectively in fact that JI bypasses are used in the lab to create sepsis in animal experimental models. For these reasons, most JI bypasses were reversed by a second operation. As of 2007, patients with an intact JI bypass are rarely seen. [Jejunoileal bypass]

Vertical banded gastroplasty surgery

Vertical Banded Gastroplasty (VBG), also known as Stomach stapling, has been the most common restrictive operation for weight control. Both a band and staples are used to create a small stomach pouch. In the bottom of the pouch is an approximately 1-cm hole through which the pouch contents can flow into the remainder of the stomach and thence onto the remainder of the gastrointestinal tract. Stomach stapling is a restrictive technique for managing obesity. The pouch limits the amount of food a patient can eat at one time and slows passage of the food. Stomach stapling is more effective when combined with a malabsorptive technique, in which part of the digestive tract is bypassed, reducing the absorption of calories and nutrients. Combined restrictive and malabsorptive technique are called gastric bypass techniques, of which Roux-en-Y gastric bypass surgery (RGB) is the most common. In this technique, staples are used to form a pouch that is connected to the small intestine, bypassing the lower stomach, the duodenum, and the first portion of the jejunum.

This type of weight loss surgery is losing favor as more doctors begin using the Adjustable gastric band. The newer adjustable band does not require cutting into the stomach and does not use any staple lines, thus making it a much safer alternative. VBG is known in the medical community as a very serious and dangerous procedure. It has been classified by the AMA as a "severely dangerous" operation.

Diagram of a vertical banded gastroplasty

VBG Advantages & Disadvantages

VBG Advantages

No dumping syndrome

No nutritional deficiencies/malabsorption

VBG Disadvantages

Needs strict patient compliance to diet High fiber foods and foods with a more dense, natural consistency can become very difficult to eat, while highly refined foods cause little discomfort. Most people who regain any weight lost after surgery do so because choosing "healthier" foods are harder to digest, while "junk" food pass easily. VBG is in no way a magic bullet or pill. It must be emphasized that lifestyle changes, i.e. diet and exercise, are absolutely imperative for weight loss to occur and be maintained. Realistic expectations are imperative. Reversal of a VBG requires a much more complex and intensive surgical process than getting the VBG. When removal of a polyurethane band is involved (polyurethane was predominantly used in the 1980s and 90s), it likely has built substantial scar tissue that must also be removed, depending on how long ago the VBG took place. Removal of the staples involves stitching the previously separated parts of the stomach back together. For these reasons, a reversal should only be considered if there are serious medical complications.

Vomiting and severe discomfort if food is not properly chewed or if food is eaten too quickly. Not adjustable (as with the Adjustable gastric band (aka "Lap band")). As with any surgical procedure, there are risks of complications. It has been observed that approximately one in every hundred patients undergoing VBG die within a year. There may also be other medical complications down the road, but the risk is relatively low. Miami Herald 2005 article

Adjustable gastric band

The same effect 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." The first gastric band was patented in 1985 by Obtech Medical of Sweden (now owned by J&J/Ethicon) and is known as the Swedish Adjustable Gastric Band (SAGB). An American company, INAMED Health, later designed the BioEnterics LAP-BAND Adjustable Gastric Banding System. The LAP-BAND System was introduced in Europe in 1993. Neither of these bands were initially designed for use with keyhole surgery. The LAP-BAND System received Food and Drug Administration (FDA) approval for use in the United States in June 2001.

In 2000, the first lower pressure, wider, one-piece adjustable gastric band called the MIDband was introduced in Lyon France by Medical Innovation Development. Unlike many of the early bands this was designed specifically for laparoscopic insertion. It has swiftly become one of the leading bands placed in France. In 2002, the first lower pressure, wider, one-piece adjustable gastric band called the Bioring was introduced in France by Cousin-Biotech.Unlike many of the early bands this was designed specifically for laparoscopic insertion. It has swiftly become one of the leading bands placed in France. There are now many band manufacturers (approx 7-8 in total).

Diagram of an adjustable gastric banding

A laparoscopic adjustable gastric band is a restrictive device implanted via bariatric surgery and designed for obese patients with a body mass index (BMI) of 40 or greater—or between 35–40 in cases of patients with certain comorbidities that are known to improve with weight loss, such as sleep apnea, diabetes, osteoarthritis, or metabolic syndrome, among others. The gastric band is an inflatable silicone prosthetic device that is placed around the top portion of the stomach, usually via laparoscopic surgery.

Comparison with other bariatric surgeries

Gastric band placement, unlike malabsorptive weight loss surgery (e.g. Roux-en-Y gastric bypass surgery (RNY), Biliopancreatic Diversion (BPD) and Duodenal Switch (DS)), does not cut or remove any part of the digestive system. It is also usually easy to remove the band and reverse the surgery, requiring only a laparoscopic procedure, after which the stomach usually returns to its normal pre-banded state. Unlike those who have procedures such as RNY, DS, or BPD, it is unusual for gastric band patients to experience any nutritional deficiencies or malabsorption of micro-nutrients. Calcium supplements and Vitamin B12 injections are not routinely required following gastric banding (as they are with RNY, for example). Gastric dumping syndrome issues also do not occur since no intestines are removed or re-routed.

Initial weight loss is slower than with RNY, generally 1-2 pounds per week; however, statistics indicate that over a 5-year period, weight loss outcome is similar. Weight regain is possible with ANY weight loss procedures including the more radical procedures that initially result in rapid weight loss. The World Health Organization recommendation for weight loss is ½ to 1 kilogram per week and an average banded patient may lose this amount. Clearly this is variable based on the individual and their personal circumstances, motivation, and mobility.

Benefits of gastric banding when compared to other bariatric surgeries:

Lower mortality rate: only 1 in 2000 versus 1 in 200 for Roux-en-Y gastric bypass surgery Fully reversible: stomach returns to normal if the band is removed No cutting or stapling of the stomach Short hospital stay Quick recovery Adjustable without additional surgery No malabsorption issues (because no intestines are bypassed) Fewer life threatening complications

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, following the major curve. The open edges are then attached together (often with surgical staples) to form a sleeve or tube with a banana shape. The procedure permanently reduces the size of the stomach. The procedure is performed laparoscopically and is not reversible.

Procedure:

Sleeve gastrectomy is usually performed on extremely obese patients, with a body mass index of 60 or more, where the risk of performing a gastric bypass or duodenal switch procedure may be too large. A two-stage procedure is performed: the first is a sleeve gastrectomy, and the second is a conversion into a gastric bypass or duodenal switch. Patients usually lose a large quantity of their excess weight after the first sleeve gastrectomy procedure alone, but if weight loss ceases the second step is performed.

For patients that are obese but not extremely obese, sleeve gastrectomy alone is a suitable operation with minimum risks. Some surgeons even prefer it over gastric banding, because it eliminates the need of having to insert a foreign body. The sleeve gastrectomy currently is acceptable weight loss surgery option for obese patients as a single procedure. Most surgeons prefer to use a bougie between 32 - 40 Fr with the procedure and the approximate remaining size of the stomach after the procedure is about 2 ounces.

Complications

Like any surgical operation, sleeve gastrectomy has possible complications, such as leakage, dilation of the sleeve (which allows for more food intake) and other usual complications associated with bariatric surgery. Patients are advised not to smoke after undergoing sleeve gastrectomy as smoking would cause serious complications, especially for persons of Lebanese descent.

Gastric Bypass Surgery

The most common form of gastric bypass surgery is Roux-en-Y gastric bypass surgery. 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. In the U.S, approximately 140,000 gastric bypass procedures were performed in 2005, an amount dwarfing the number of Lap-Band, duodenal switch and vertical banded gastroplasty procedures done. Furthermore, since the gastric bypass has been performed for almost 50 years, surgeons have become very comfortable with the understanding of the risks and benefits of the procedure. By sheer volume of cases combined with the volume of scientific research, the gastric bypass has become the "gold standard" operation for weight loss in the U.S. An emerging factor in the success of gastric bypass surgery is following an established gastric bypass diet after surgery

Roux-en-Y gastric bypass

Sleeve gastrectomy with duodenal switch

A variation of the biliopancreatic diversion includes a Duodenal switch. The part of the stomach 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 intestine. The duodenum and the upper part of the small intestine are reattached to the rest at about 75-100 cm from the colon.

Diagram of a sleeve gastrectomy with duodenal

switch.

Complications of Abdominal Surgery

Infection Infection of the incisions, or of the inside

of the abdomen (peritonitis, abscess) may occur, due to release of bacteria from the bowel during the operation. Nosocomial infection, such as pneumonia, bladder or kidney infections, and sepsis (bloodborne infection) are also possible. Effective short-term use of antibiotics, diligent respiratory therapy, and encouragement of activity within a few hours after surgery, can reduce the risks of infections.

Hemorrhage Many blood vessels must be cut in order

to divide the stomach and to move the bowel. Any of these may later begin bleeding, either into the abdomen (intra-abdominal hemorrhage), or into the bowel itself (gastrointestinal hemorrhage). Transfusions may be needed, and re-operation is sometimes necessary. Use of blood thinners, to prevent venous thromboembolic disease, may actually increase the risk of hemorrhage slightly.

Hernia A hernia is an abnormal opening, either within

the abdomen, or through the abdominal wall muscles. An internal hernia may result from surgery, and re-arrangement of the bowel, and is mainly significant as a cause of bowel obstruction. An incisional hernia occurs when a surgical incision does not heal well; the muscles of the abdomen separate and allow protrusion of a sac-like membrane, which may contain bowel or other abdominal contents, and which can be painful and unsightly. The risk of abdominal wall hernia is markedly decreased in laparoscopic surgery.

Bowel obstruction Abdominal surgery always results in

some scarring of the bowel, called adhesions. A hernia, either internal or through the abdominal wall, may also result. When bowel becomes trapped by adhesions or a hernia, it may become kinked and obstructed, sometimes many years after the original procedure. Usually an operation is necessary to correct this problem.

Venous thromboembolism Any injury, such as a surgical operation, causes

the body to increase the coagulation of the blood. Simultaneously, activity may be reduced. There is an increased probability of formation of clots in the veins of the legs, or sometimes the pelvis, particularly in the morbidly obese patient. A clot which breaks free and floats to the lungs is called a pulmonary embolus, a very dangerous occurrence. Commonly, blood thinners are administered before surgery, to reduce the probability of this type of complication.