The prevalence of morbid obesity has risen more than fourfold since 1986.¹ Currently, 1.7 billion people worldwide are considered obese and approximately 60% of the U.S. population is overweight. In excess of 100 billion dollars is spent annually on obesity health care–related costs.

To be considered morbidly obese, one must have either a body mass index (BMI) greater than 40 kg/m² or a BMI of 35 to 40 kg/m² with comorbid conditions.² More than 15 million Americans currently have BMI levels that make them eligible for bariatric surgery.³ In the United States only about 1% of eligible patients undergo bariatric surgery.

Morbid obesity promotes the development of diabetes mellitus, hypertension, dyslipidemia, cardiovascular disease, gastroesophageal reflux, asthma, and obstructive sleep apnea. Premature death from obesity now rivals the mortality rates related to smoking, with more than 300,000 deaths attributable to obesity per year.⁴

Bariatric surgery is the most effective and durable treatment to achieve weight loss and its associated comorbidity. Five-year mortality is reduced 89% in severely obese patients who undergo weight loss surgery.^5,⁶ Fifteen-year survival increases by one third in patients who undergo bariatric surgery in comparison with those who do not. New laparoscopic surgical techniques have contributed to the growing demand for and acceptance of bariatric surgery. Approximately 4925 bariatric procedures were performed in 1990, as compared with an estimated 220,000 in 2008. Bariatric surgery is now the second most common abdominal operation in the United States.

Women are more likely than men to choose bariatric surgery. It is estimated that men make up 36% of the morbidly obese population in the United States, although they account for less than 20% of patients choosing weight loss surgery each year. The typical demographic profile of a bariatric surgery patient is a woman 35 to 49 years of age with private insurance who belongs to a higher socioeconomic class.

Recent trends suggest that higher-risk, older patients are undergoing bariatric procedures with greater frequency; surprisingly, they demonstrate postoperative morbidity and mortality rates similar to those in the general population.⁷ Rates of perioperative complications, reoperation, hospital readmission, and emergency department (ED) visits have been falling. The rates for these indicators are highest with gastric bypass followed by sleeve gastrectomy and lowest for laparoscopic adjustable gastric banding (LAGB).⁸ Overall, in-hospital mortality rates are between 0.05% and 0.2%, and 30-day mortality rates have been reported to range between 0.05% and 2%.

Complications of bariatric surgery are common and are generally initially treated in the ED. Up to 20% of patients are admitted for a postoperative complication within 1 year of the bariatric procedure; this rate increases to 40% within 3 years. The potential postoperative complications of the various bariatric procedures have predictable timing and clinical manifestations.⁹

Types of Bariatric Surgery: Roux-en-Y and Gastric Banding

The two most common types of bariatric surgery in the United States are the Roux-en-Y gastric bypass (RYGBP) (54%) and adjustable gastric banding (39%). Adjustable gastric banding continues to rapidly gain in popularity since initial federal approval in 2001.⁷

Caloric restriction and malabsorption are the principal means of weight loss. In the United States, weight loss procedures that combine both restrictive and malabsorptive components are the most popular. RYGBP, biliopancreatic diversion (BPD), and BPD with duodenal switch are examples of techniques that involve both malabsorption and restriction. In Europe, the preference is for purely restrictive bariatric procedures.

Malabsorption

Surgical techniques that induce malabsorption were the first attempted. Malabsorptive techniques were thought to be the most effective method of achieving rapid and sustained weight loss. Surgeons initially connected the proximal jejunum to a distal portion of the ileum or ascending colon in a procedure known as jejunoileal bypass (Fig. 47.1). This technique resulted in severe diarrhea, dangerous metabolic derangements, arthropathy, renal calculi, gallstones, liver disease, and short bowel syndrome. Gastric bypass has been shown to be a more effective malabsorptive procedure with fewer side effects than those associated with jejunoileal bypass. Malabsorptive procedures still in current use include laparoscopic RYGBP, BPD, duodenal switch, and isolated intestinal bypass.

Fig. 47.1 Jejunoileal bypass.

Restriction

Purely restrictive procedures are less effective than malabsorptive techniques.⁶ Restrictive surgeries act by reducing oral intake through induction of early satiety. However, some areas of the stomach easily dilate over time, which causes gradual increases in perceived hunger and subsequent food intake. Restrictive procedures are more successful when the lesser-curve gastric pouch is 15 mL or smaller.⁴ Restrictive weight loss procedures such as vertical banded gastroplasty and isolated partial gastrectomy (sleeve gastrectomy) have fallen out of favor. LAGB is the most common, poses the least risk, and is the most effective restrictive technique currently performed.¹⁰

Roux-en-Y Gastric Bypass

The RYGBP procedure creates a gastric pouch from the proximal portion of the lesser curvature of the stomach that can hold about 15 to 30 mL of fluid and food (Fig. 47.2). A portion of the distal end of the small bowel is connected to this pouch to create a concurrent malabsorptive process. Historically, RYGBP was an open procedure, but currently the majority are performed laparoscopically.

Fig. 47.2 Roux-en-Y gastric bypass.

Early postoperative complications of RYGBP include obstruction of the bypassed small bowel segment, obstruction of the Roux limb, anastomotic leak, and gastrointestinal (GI) or intraperitoneal bleeding. Pulmonary embolism, a rare postoperative complication, remains the most common cause of postoperative death, followed by complications resulting from anastomotic leaks. Other complications include pneumonia, myocardial infarction, renal failure secondary to rhabdomyolysis, and nutritional deficiencies.

Late complications generally involve both anatomic and systemic complications. Anatomic complications include esophageal reflux, chronic abdominal pain, internal hernias, ulcers, stricture, stenosis, and bowel obstruction. Systemic complications are manifested mostly as nutritional deficiencies.¹¹ Clinical manifestations include anemia (iron deficiency), osteopenic fractures (calcium deficiency), fatigue and lower extremity edema (protein-calorie malnutrition), chronic pain and proximal muscle weakness (vitamin D deficiency), visual deficits (vitamin A deficiency), and vague neurologic symptoms (thiamine, folate, and vitamin B₁₂ deficiencies).

Complications of Open versus Laparoscopic Procedures

Wound infections and incisional hernias are more common with open bariatric procedures (7% and 9%, respectively) than with laparoscopic procedures (3% and 0.5%, respectively). Patients who have undergone laparoscopic gastric bypass have a slightly higher rate of small bowel obstruction, anastomotic stomal stenosis, internal hernias, and GI hemorrhage. Pulmonary embolism, pneumonia, and anastomotic leaks have similar incidences after both open and laparoscopic procedures. Stomal stenosis manifested as postprandial epigastric pain and vomiting of undigested food is thought to be more common after laparoscopic RYGBP because a mechanical stapler is used instead of the hand-sewn methods with open RYGBP. Endoscopy often both diagnoses and treats this complication.

Specific Clinical Presentations

Persistent, severe vomiting can be caused by anastomotic strictures. Strictures can usually be treated by endoscopic balloon dilation but occasionally require surgical revision. Some episodes of nausea and vomiting are common during the immediate postoperative period, but if the vomiting persists, an anastomotic stricture may have formed.

Obstruction of the Roux limb requires percutaneous decompression. Patients with such an obstruction experience nausea, vomiting, abdominal pain, and distention. Diagnosis may require computed tomography (CT).

The occurrence of acute fever and tachycardia within weeks of a Roux-en-Y procedure suggests an anastomotic leak with or without abscess formation. The symptoms are often subtle but can include dyspnea, unexplained sepsis, changes in mental status, and restlessness. Peritoneal signs are often lacking. Because abdominal examination of morbidly obese patients is unreliable, the diagnosis is best accomplished through imaging studies. CT of the abdomen and pelvis with oral and intravenous (IV) administration of a contrast agent is the modality of choice. If the patient is unable to undergo CT because of the weight limitations of the CT table, an upper GI radiographic series should be obtained. The false-negative rate is high (up to 44%) with CT and other imaging studies for the evaluation of anastomotic leaks. Laparoscopy should be considered in cases of negative imaging but high pretest probability of an anastomotic leak.^12,¹³

Esophageal reflux occurs infrequently after this procedure but may represent damage to the lower esophageal sphincter or impaired gastric emptying secondary to a distal obstruction. Overfilling of the pouch, operative vagal nerve injury, or stomal stricture can lead to gastroesophageal reflux disease (GERD). Educating patients to avoid overeating, chew food properly, use acid suppression medication, and eat small frequent meals reduces the incidence of GERD.

Diarrhea with malodorous flatulence may result from a short Roux limb and usually resolves spontaneously. Persistent diarrhea after weight stabilization, however, should raise suspicion of bacterial overgrowth in the bypassed tract.

Dumping syndrome consisting of abdominal cramping, nausea, vomiting, and diarrhea can be seen immediately postoperatively and may last up to 12 to 18 months. Noncompliance with diet is the most common and preventable cause. Treatment includes rehydration, electrolyte correction, and education of the patient regarding diet.

Constipation may result from decreased fiber intake.

Cholelithiasis may develop during the period of initial rapid weight loss. Biliary colic and cholecystitis are high on the differential diagnosis list for abdominal pain in patients with ongoing reductions in weight. Prophylactic cholecystectomy was often performed during open RYGBP. The transition to laparoscopic surgery for most RYGBP procedures has led to a decrease in prophylactic cholecystectomy and thus an increase in cholelithiasis rates.

Bleeding may occur at any anastomotic site but is most common and dangerous in the gastrojejunostomy area. It often results in melena, hematemesis, hematochezia, or hypotension (or any combination of these findings) secondary to upper GI bleeding. Upper endoscopy is the most reliable way to confirm blood loss from this site. Bleeding at other anastomotic sites (jejunojejunostomy and the transected gastric remnant) is usually self-limited and managed nonoperatively.¹¹ Stomal ulcers can occur 2 to 4 months after surgery and are identified by endoscopy. Many can be treated on an outpatient basis with proton pump inhibitors or sucralfate.

Laparoscopic Adjustable Gastric Banding

The LAP-BAND (Allergan, Inc., Irvine, CA) is an adjustable device that is laparoscopically secured around the upper portion of the stomach (Fig. 47.3). The band is connected by a tube to a port implanted under the skin. Surgeons may adjust the extent of constriction (restriction) of the LAP-BAND by injecting saline into the subcutaneous port. Increased restriction limits food intake; adjustments can be made in response to adverse symptoms or patient preference, thereby allowing some control over the weight loss process. Operative risks for LAGB are less than those for RYGBP.

Fig. 47.3 Laparoscopic adjustable gastric banding.

In 2007 the Food and Drug Administration (FDA) approved a second gastric banding device called the Realize Adjustable Gastric Band. The Heliogast and Midband adjustable gastric bands are available only outside the United States and have not been approved by the FDA. All gastric banding devices work similarly. In 2011 the U.S. FDA approved expanding the use of gastric banding surgery for an additional 27 million American patients with mild obesity (BMI of 30 to 35 kg/m²) who have one obesity-related health condition (e.g., hypertension, diabetes mellitus).

Complications

LAGB is generally performed as outpatient surgery. Immediate postoperative vomiting is usually caused by gastric wall edema under the band. Inflation of the band during surgery increases the likelihood of gastric wall edema. IV hydration is required until the edema subsides. Maintenance of nothing by mouth (NPO) and IV steroids are thought to increase the resolution rate.

Immediate postoperative vomiting or dysphagia may also be due to gastroesophageal obstruction caused by proximal band slippage (1% to 3%). Gastric dilation and food intolerance may develop. Gastric necrosis and perforation may result from band migration at any time. A GI swallow study using fluoroscopy is the preferred method of diagnosing band migration, but a two-view upper GI contrast study or abdominal radiograph may capture the position of the radiolucent band. An abdominal CT scan may also demonstrate movement of the band. Band slippage is the most common LAGB complication occurring early to late in the postoperative period. Band slippage rates are decreasing, however, with new placement techniques.

Any patient with signs of obstruction after LAGB should undergo immediate deflation of the band. Emergency physicians can deflate an adjustable gastric band by accessing the subcutaneous anterior abdominal port (see Fig. 47.3). A noncoring Huber needle should be used to remove the amount of saline injected during the previous two adjustments. The patient should know this volume of saline, but if not, one can aspirate all the saline in the reservoir. Fluoroscopy or ultrasound may be required if the port cannot be accessed easily. A GI swallow study and surgical consultation should be obtained after any band deflation. Symptoms should resolve over a couple of days after deflation. Surgery is often required to definitively repair gastric band slippage.

Gastric stoma obstruction by food, swelling, or hematoma can be an early or late complication. Partial obstruction can be treated conservatively with hydration and NPO status. Complete obstruction often requires band deflation and surgery to reposition the band.

Band erosion can occur in up to 4% of patients over time. The band can erode and migrate silently into the stomach. Peritonitis is often absent, but GI bleeding and bowel obstruction can occur. Port site infections may be the first sign of band erosion, and endoscopy is the best method to diagnose band erosion. Upper GI studies and CT scans can assist in making the diagnosis as well. Removal of the band and repair of the stomach are required.

Gastric injury as a result of stomach perforation occurs rarely. One to 2 days following band placement an acute abdomen may develop. IV fluids, broad-spectrum antibiotics, NPO status, and surgical consultation with subsequent repair of the stomach are required.

Gastric necrosis of the stomach wall is a late complication that often results from ischemia caused by a combination of gastric prolapse—the part of the stomach below the band herniates up through the device (Fig. 47.4) and pressure from the band. Patients appear ill, with an acute abdomen. Upper GI studies or CT scans show an overly distended gastric pouch. Patients require emergency surgery to remove the band and repair the stomach wall.

Fig. 47.4 Gastric prolapse.

Esophageal and gastric pouch dilation occurs when the band is too tight or patients are not compliant with their diet. The symptoms are similar to those seen with gastric slippage. Upper GI contrast studies make the diagnosis. Treatment is band deflation and close follow-up with the bariatric physician. Prolonged dilation can result in chronic esophageal dysmotility, severe achalasia, and GERD, which is not always reversible (13%) with band deflation and removal.¹⁴

Device malfunction can cause port infections, tube leakage, tube disconnection, and skin ulceration. Plain radiographs, abdominal CT scans, and upper endoscopy may all aid in the diagnosis of gastric erosion and device malfunction.

Recent controversies have arisen regarding the long-term complications of gastric banding. Few long-term studies have been performed, but a recent 14-year study (1995 to 2009) of gastric band surgery showed high complication and reoperation rates. Reoperation because of complications was reported to occur in 30% of patients, band removal was needed in 12%, and weight regain began after 5 years of follow-up.¹⁵ Still, gastric banding has been shown to have a lower mortality rate than other bariatric surgeries, is less invasive, and is reversible.

Biliopancreatic Diversion

BPD is popular in Italy (Fig. 47.5). The procedure involves a distal gastrectomy that leaves a 250-mL stomach capacity with a drastic intestinal bypass. Half of the jejunum and ileum are disconnected and reconnected near the terminal ileum. This procedure is particularly effective for severely obese patients (BMI > 50 kg/m²), in whom it causes significant weight loss and reduced morbidity. Less bacterial overgrowth occurs in the bypassed intestine because it is continuously exposed to bile and pancreatic enzymes. Serious complications can result, however, particularly the metabolic abnormalities and nutritional deficiencies seen after aggressive malabsorptive procedures. Hepatic dysfunction can develop in 2% of patients undergoing BPD.

Fig. 47.5 Biliopancreatic diversion.

Duodenal Switch and Sleeve Gastrectomy

The duodenal switch procedure is similar to BPD, but the jejunum is connected to the proximal duodenum rather than the ileum (Fig. 47.6). This operation is also known as the biliopancreatic diversion–duodenal switch (BPD-DS) procedure. It is considered an improvement on BPD alone because the length of the small intestine is increased to 100 cm, which allows better absorption of nutrients.

Fig. 47.6 Duodenal switch.

A linear (sleeve) gastrectomy in which a restrictive pouch of the lesser curvature is left is also performed during the duodenal switch. BPD-DS with sleeve gastrectomy allows gastric emptying to be somewhat regulated through preservation of a functioning pylorus. The risk for dumping syndrome is subsequently reduced.

Some surgeons prefer to perform only a sleeve gastrectomy in high-risk patients (Fig. 47.7). This simple restrictive procedure avoids intestinal bypass and anastomoses of the GI tract. Side effects such as nutritional deficiencies are rare because only mild malabsorption results from sleeve gastrectomy alone.