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WEIGHT LOSS SURGERY: STATE OF THE ART

WEIGHT LOSS SURGERY: STATE OF THE ART
WEIGHT LOSS SURGERY: STATE OF THE ART
  • Key Points
  • Patients with a BMI of 40 kg/m2, or 35 kg/m2 with severe comorbidities of obesity, qualify for weight loss surgery. • The type of weight loss procedure performed can have differential effects on weight loss and on long-term nutritional status.
  • Most medical comorbidities associated with obesity improve after surgically induced weight loss.
  • The most commonly performed procedure is Roux-en-Y gastric bypass.
  • Laparoscopic approaches are becoming increasingly common.

OBESITY


Obesity is defined as the accumulation of excess body fat that leads to pathology. This disease can lead to an extensive list of comorbid conditions, the most serious of which are:

• hypertension,

• diabetes,

• heart disease,

• stroke,

• obstructive sleep apnea, and

• degenerative joint disease.

Body mass index (BMI = weight (kg)/height (m)2) is the primary measurement used to categorize obese patients. In 1991, the National Institutes of Health (NIH) defined morbid obesity as a BMI of 35kg/m2 or greater with severe obesityrelated comorbidity, or a BMI of 40kg/m2 or greater without comorbidity.1 Patients with a BMI of 50kg/m2 or greater are often referred to as superobese or massively obese. There has been increasing interest in obesity and major advances in bariatric surgery over the past 15 years as the problems associated with morbid obesity and the benefits of surgical treatment for this disease have become more clearly defined.
Epidemiology and risk factors Obesity is a major public health problem in the USA that has significantly worsened over the past four decades and has
now reached epidemic proportions. The National Center for Health Statistics has conducted periodic National Health and Nutrition Examination Surveys (NHANES) since 1960 to determine the prevalence of obesity.2 According to this continuous study, 65% of US adults are overweight (BMI >25kg/m2) or obese (BMI >30kg/m2). These studies have shown an increase in the prevalence of obesity from 15% in 1980 to 30% in 2002. Additionally, 5% of Americans 20 years of age or older currently have a BMI >40kg/m2. Children and older Americans are increasingly becoming obese as well. Thirtyone percent of children aged 6–19 are at risk for overweight (BMI for age >85th percentile) or overweight (BMI for age >95th percentile), and 16% are overweight. Thirty-three percent of Americans over the age of 60 are obese. These increases have occurred despite expenditures of over $45 billion annually on weight loss products.3 Obesity and morbid obesity affect women and minorities (particularly middle-aged black and Mexican American women) more than white males. However, in almost every age and ethnic group examined by NHANES, the prevalence of overweight or obesity exceeds 50%.2
Etiology The etiology of obesity is not as straightforward as once thought. It is not simply an excess of caloric intake in relation to caloric expenditure, but a complex interaction of excessive intake, inefficient calorie utilization, reduced metabolic activity, a reduction in the thermogenic response to meals, and an abnormally high set-point for body weight. Genetic, environmental, and psychosocial factors all contribute to this problem. Children of obese parents have an 80–90% chance of developing obesity by adulthood, while only 10% of children of normal-weight parents will become obese. The high-fat and high-calorie American diet in conjunction with a sedentary lifestyle contributes significantly to this problem.
OVERVIEW OF BARIATRIC SURGERY
This section provides an overview of the different weight loss procedures and their physiologic effects.


Obesity is defined as the accumulation of excess body fat that leads to pathology. This disease can lead to an extensive list of comorbid conditions, the most serious of which are:

• hypertension,

• diabetes,

• heart disease,

• stroke,

• obstructive sleep apnea, and

• degenerative joint disease. Body mass index (BMI = weight (kg)/height (m)2) is the primary measurement used to categorize obese patients. In 1991, the National Institutes of Health (NIH) defined morbid obesity as a BMI of 35kg/m2 or greater with severe obesityrelated comorbidity, or a BMI of 40kg/m2 or greater without comorbidity.1 Patients with a BMI of 50kg/m2 or greater are often referred to as superobese or massively obese. There has been increasing interest in obesity and major advances in bariatric surgery over the past 15 years as the problems associated with morbid obesity and the benefits of surgical treatment for this disease have become more clearly defined.
Epidemiology and risk factors Obesity is a major public health problem in the USA that has significantly worsened over the past four decades and has
now reached epidemic proportions. The National Center for Health Statistics has conducted periodic National Health and Nutrition Examination Surveys (NHANES) since 1960 to determine the prevalence of obesity.2 According to this continuous study, 65% of US adults are overweight (BMI >25kg/m2) or obese (BMI >30kg/m2). These studies have shown an increase in the prevalence of obesity from 15% in 1980 to 30% in 2002. Additionally, 5% of Americans 20 years of age or older currently have a BMI >40kg/m2. Children and older Americans are increasingly becoming obese as well. Thirtyone percent of children aged 6–19 are at risk for overweight (BMI for age >85th percentile) or overweight (BMI for age >95th percentile), and 16% are overweight. Thirty-three percent of Americans over the age of 60 are obese. These increases have occurred despite expenditures of over $45 billion annually on weight loss products.3 Obesity and morbid obesity affect women and minorities (particularly middle-aged black and Mexican American women) more than white males. However, in almost every age and ethnic group examined by NHANES, the prevalence of overweight or obesity exceeds 50%.2
Etiology The etiology of obesity is not as straightforward as once thought. It is not simply an excess of caloric intake in relation to caloric expenditure, but a complex interaction of excessive intake, inefficient calorie utilization, reduced metabolic activity, a reduction in the thermogenic response to meals, and an abnormally high set-point for body weight. Genetic, environmental, and psychosocial factors all contribute to this problem. Children of obese parents have an 80–90% chance of developing obesity by adulthood, while only 10% of children of normal-weight parents will become obese. The high-fat and high-calorie American diet in conjunction with a sedentary lifestyle contributes significantly to this problem.
OVERVIEW OF BARIATRIC SURGERY
This section provides an overview of the different weight loss procedures and their physiologic effects.

Goals of surgery and mechanism of action The goal of bariatric surgery is to improve the health of morbidly obese patients by reducing or eliminating their comorbid conditions. This is achieved by long-term weight loss that involves a significant reduction in caloric intake or absorption. Bariatric operations that are currently performed involve: • gastric restriction (vertical banded gastroplasty, VBG) (Fig. 1.1) or laparoscopic adjustable gastric banding (LAGB) (Fig. 1.2),
1 Weight loss surgery: state of the art


Figure 1.1 Vertical banded gastroplasty (VBS).


Figure 1.2 Adjustable gastric band (LAGB).


Figure 1.3 Biliopancreatic diversion with duodenal switch (BPD with or without DS).


• malabsorption (biliopancreatic diversion, BPD) or biliopancreatic diversion with duodenal switch (BPD-DS) (Fig. 1.3), or

• a combination of restriction and malabsorption (Roux-en-Y gastric bypass, RYGB) (Fig. 1.4). Between 1998 and 2003, the number of bariatric operations performed in the USA increased from 13000 to 103000 per year.4 During that period, the percentage of gastroplasty procedures performed declined from 25% to 7%. Gastric bypass procedures comprise over 80% of bariatric procedures currently performed in the USA and 65% of bariatric procedures performed worldwide (Table 1.1).5 The choice of operation depends largely on patient preference. There are currently no data available to preoperatively predict which operation a specific patient should undergo.

In surveys from the USA and Australia, safety and invasiveness had the greatest impact on patient choice for bariatric operations.6 Most patients in the USA are currently seeking either gastric bypass or adjustable gastric-banding procedures, and the relative risks and benefits of each must be carefully explained.

• Gastric bypass generally provides more weight loss in a shorter time than LAGB does, but it is more invasive and has a higher mortality rate than LAGB.

• Adjustable gastric banding has the lowest mortality rate of any procedure currently used, but it generally results in less weight loss than with RYGB and involves a permanent foreign body in the abdomen. Follow-up requirements must be considered preoperatively as well. Gastric bypass requires lifelong vitamin supplementation that can be a cost burden for some patients, while LAGB requires more frequent follow-up visits for band adjustments in
the first year after surgery. BPD and duodenal switch procedures are performed at a few specialized centers and are more likely to be performed in superobese patients or patients specifically seeking these operations. Restrictive procedures work by reducing the quantity of food that can be consumed at one time. In the case of LAGB, the degree of restriction can be increased or decreased based on the patient’s weight loss. Malabsorptive procedures ensure that
ingested food and digestive enzymes remain separated for a substantial bowel length to limit caloric absorption. RYGB provides a combination of restriction and decreased absorption. The restrictive component of the operation consists of the creation of a small (15–30mL) gastric pouch. The standard Roux limb is 75cm in length and results in mild, and probably transient, malabsorption. The long-limb (150cm) RYGB used for superobese patients results in a greater degree of malabsorption. The rapid reduction of comorbidities such as diabetes and the long-term weight loss achieved by RYGB and BPD cannot be explained exclusively by restriction or malabsorption. Other mechanisms of weight loss and glucose control following bariatric surgery are being investigated.

• Ghrelin, a peptide hormone produced by the stomach and duodenum, is normally released prior to meals and acts on the hypothalamus to increase appetite. Alterations in ghrelin production may play a role in the decreased appetite and sustained weight loss seen after certain bariatric procedures.

• Other gut hormones, such as peptide YY, glucagon-like peptide-1, and glucose-dependent insulinotropic peptide, may also contribute to the early satiety and rapid reduction of insulin resistance seen after bariatric surgery.

• Obesity is associated with a proinflammatory and prothrombotic state. Increased adipocyte activity, and the associated increase in circulating inflammatory cytokines, may be related to many of the cardiovascular risk factors seen with obesity. Preliminary studies have demonstrated improvement in these detrimental cytokines and adipokines after surgical weight loss.
Evolution of bariatric surgery The initial operations to treat morbid obesity were performed in the 1950s and were malabsorptive procedures. The jejunocolic and jejunoileal bypass procedures resulted in electrolyte disturbances and liver failure. In 1967, Mason and Ito developed the gastric bypass procedure by creating a 50- to 100-mL proximal gastric pouch that emptied into a loop gastrojejunostomy.7 Modifications to this procedure over the past 35 years have been directed towards minimizing the complications of bile reflux, anastomotic ulcers, and gastrogastric fistulas, and have resulted in the current Roux-en-Y divided gastric bypass. In the late 1970s, Scopinaro developed the BPD procedure.8 In this procedure, the small bowel is divided 250cm proximal to the ileocecal valve, and the alimentary limb is anastomosed to the gastric pouch. The duodenal switch (BPD-DS) is a modification of BPD in which the pylorus is left intact to prevent marginal ulceration and improve gastric emptying. Gastric banding was also developed in the late 1970s, and the initial use of fixed banding material to create a proximal gastric pouch has evolved into the laparoscopic placement of an adjustable gastric band.
Indications

• Patients with a BMI >35kg/m2 with obesity-related comorbidities, and those with a BMI >40kg/m2 with or without comorbidities, are eligible for bariatric surgery.
Overview of bariatric surgery
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Table 1.1 Types of bariatric procedure performed
Procedure USA (%) Worldwide (including USA) (%)
Gastric bypass 80 65 Laparoscopic 5–10 25 adjustable gastric band Vertical banded <5 5 gastroplasty Biliopancreatic 5–10 5 diversion/duodenal switch (Adapted from Buchwald and Williams 2004,5 with permission.) Figure 1.4 Roux-en-Y gastric bypass (RYGB).

• Patients must have attempted medical weight loss programs and should be highly motivated to change their lifestyle after surgery.

• The majority of patients undergoing bariatric surgery are between ages 18 and 60. There was insufficient evidence at the time of the 1991 NIH consensus to make recommendations about surgery at the extremes of age. There is a growing body of evidence, however, that supports bariatric surgery in carefully selected adolescents and in the elderly (>60 years). The current indications for bariatric surgery may broaden as long-term safety and efficacy studies in these patient groups become available.
Contraindications

• Patients who cannot tolerate general anesthesia due to cardiac, pulmonary, or hepatic insufficiency are not candidates for surgery.

• Additionally, patients must be able to understand the consequences of the surgery and comply with the extensive preoperative evaluation and the postoperative lifestyle changes, diet, vitamin supplementation, and follow-up program.

• Patients who have ongoing substance abuse or unstable psychiatric illness are poor candidates for bariatric surgery.
Preparation for surgery Surgical candidates must complete a thorough medical evaluation, a psychologic evaluation, and have preoperative testing appropriate for their comorbid conditions. There are over 30 comorbidities associated with obesity, and many of these predispose bariatric surgical patients to increased perioperative risk (Table 1.2). Because morbidly obese patients are at higher risk for having hypertension, diabetes, coronary artery disease, left ventricular hypertrophy, congestive heart failure, and pulmonary hypertension, an electrocardiogram should be performed on every patient, and a preoperative cardiology evaluation should be performed when there is evidence of cardiovascular disease. Obstructive sleep apnea is frequently occult in this patient population until a thorough history prompts a preoperative evaluation. Patients with symptoms of loud snoring or daytime hypersomnolence should undergo polysomnography and, if positive, be treated with nasal continuous positive airway pressure (CPAP). Because these patients are at risk for upper airway obstruction, close monitoring and nasal CPAP should continue postoperatively. Asthma and obesity hypoventilation syndrome (chronic hypoxemia, hypercarbia, pulmonary hypertension, and polycythemia) are also severe pulmonary complications of obesity and should be evaluated by a pulmonologist preoperatively. Upper gastrointestinal barium studies and endoscopy should be performed for patients with severe gastroesophageal reflux symptoms. Because the incidence of gallstones is high in this population, preoperative abdominal sonography is routinely performed in many centers.
All bariatric patients should undergo thorough nutritional evaluation and counseling preoperatively. Patients must understand how their diet will change after surgery, and what supplements are necessary to prevent specific nutritional deficiencies. The dietitian plays a key role in determining whether a patient understands the significant changes in diet that will occur after bariatric surgery. Psychologic testing is performed preoperatively to assess patients’ expectations and to ensure that there are no active psychiatric issues that would put the patient at risk for failure or poor compliance postoperatively.
Surgical techniques Worldwide, two-thirds of bariatric procedures are performed laparoscopically.5 Adjustable gastric banding is performed

4-
Table 1.2 Comorbidities associated with obesity
System Comorbidities
Cardiovascular Hyperlipidemia Heart failure Myocardial infarction Hypertension Stroke Left ventricular hypertrophy Venous stasis ulcers/thrombophlebitis Pulmonary Asthma Obstructive sleep apnea Obesity hypoventilation syndrome Pulmonary hypertension Endocrine Insulin resistance Type 2 diabetes Polycystic ovarian syndrome Hematopoetic Deep venous thrombosis Pulmonary embolism Gastrointestinal Gallstones Gastroesophageal reflux disease Abdominal hernia Genitourinary Stress urinary incontinence Urinary tract infections Obstetric/gynecologic Infertility Miscarriage Fetal abnormalities and infant mortality Musculoskeletal Degenerative joint disease Gout Plantar fasciitis Carpal tunnel syndrome Neurologic/psychiatric Intracranial hypertension Depression Anxiety
exclusively with the laparoscopic approach. Gastric bypass is performed open or laparoscopically, and the approach is primarily determined by the surgeon’s training and advanced laparoscopic skills. Some bariatric surgeons perform open RYGB exclusively; others selectively choose the open approach for patients with very high BMIs or multiple prior abdominal operations. Previous abdominal surgery is not a contraindication to the laparoscopic approach, though, and revisional bariatric surgery (conversion of a failed VBG to a RYGB) can be accomplished laparoscopically. Some surgeons advocate performing all gastric bypass procedures with the open technique due to shorter operating times and lower costs, but the introduction of laparoscopy into bariatric surgery has increased the public’s demand for this minimally invasive approach and attracted surgeons who are interested in advanced laparoscopic procedures. As experience is gained with the laparoscopic RYGB, operative times decrease and are comparable with those of open surgery. Because of the complexity of the procedures, BPD and BPD-DS have primarily been performed open. There are, however, small series that demonstrate the feasibility of performing these malabsorptive procedures laparoscopically.9 There are many well-documented advantages to the laparoscopic approach. The smaller incisions significantly reduce recovery time and postoperative pain compared with a laparotomy. Other benefits include:

• less surgical trauma in the wound and to the viscera;

• improved postoperative pulmonary function; and

• decreased incidence of wound-related complications such as hematomas, seromas, infections, hernias, and dehiscence.

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Assessment of results Outcomes measurement in bariatric surgery is of paramount importance. The NIH consensus conference recommended statistical reporting in bariatric surgery, and it is imperative that surgeons maintain quality outcomes databases in order to track their results, to educate patients, and to demonstrate success to professional societies and insurance companies.
Follow-up Bariatric surgery patients require lifetime follow-up. Early postoperative visits focus on complications and the dramatic changes in dietary habits. Diet is progressively advanced from liquid to solid food over the first month in consultation with the dietitian. Later follow-up visits focus on psychologic support, nutritional assessment and vitamin supplementation, and exercise programs. At the Cleveland Clinic, patient visits are at 1 week, 1 month, 3 months, 6 months, 9 months, 1 year, and annually thereafter.
Efficacy Bariatric surgery is one of the few therapies in medicine that result in the simultaneous treatment of multiple diseases. Nonsurgical weight loss programs utilizing diet, exercise, medication, and behavioral modification can induce modest short-term weight loss, but there is currently no diet or medical therapy
that results in sustained weight loss to adequately treat morbid obesity and its comorbidities. There are two randomized controlled trials comparing surgical weight loss and non-surgical weight loss.11,12 Both of these demonstrated the superiority of surgery over medical therapy in achieving long-term weight loss. The procedures used in these two trials have been replaced with the more effective and less morbid procedures used today. The Swedish Obese Subjects Study Scientific Group is a prospective, controlled, matched-pair cohort study comparing surgery with non-surgical treatment for obesity. The procedures used were VBG, gastric banding, and gastric bypass.

• After 2 years, the control group’s weight increased by 0.1%, and the surgery group had a 23.4% decrease from their preoperative weight.

• Ten-year follow-up of 1268 patients in this study revealed a weight increase of 1.6% in the control group and a weight decrease of 16.1% in the surgery group compared with preoperative weight.

• Only 3.8% of control patients achieved a 20% weight loss over the 10-year period, whereas 73.5% of the gastric bypass group, 35.2% of the VBG group, and 27.6% of the gastric-banding group achieved this level of long-term weight loss.

• Rates of recovery from hypertension, diabetes, hypertriglyceridemia, low high-density lipoprotein cholesterol, and hyperuricemia favored the surgical group at 2 and 10 years.

• The incidence of hypertension and hypercholesterolemia did not differ between groups at 10 years. This study is ongoing with respect to analyzing mortality and the incidence of cancer, myocardial infarction, and stroke.13 A metaanalysis by Buchwald et al.

analyzing 22094 patients in 136 studies found that for all bariatric procedures, the average amount of excess weight loss (EWL = the amount of weight above ideal body weight that is lost, and is assumed to be adipose tissue in most patients) was 61.2%.

• BPD or duodenal switch procedures had the highest overall EWL (70%), followed by gastroplasty (68%), gastric bypass (61%), and gastric banding (47%). • Overall, diabetes improved or resolved in 86% of patients, hyperlipidemia improved in 70%, hypertension improved or resolved in 78.5%, and obstructive sleep apnea improved or resolved in 83.6% of patients.

• Diabetes outcomes varied with operative procedure. Ninety-nine percent of BPD-DS patients, 84% of gastric bypass patients, 72% of gastroplasty patients, and 48% of gastric-banding patients had complete resolution of their diabetes.

• BPD and gastric bypass patients had the most improvements in hyperlipidemia postoperatively (99% and 97% resolution, respectively), but the reduction of blood pressure was independent of the surgical procedure performed.14 The Australian Safety and Efficacy Register of New Interventional Procedures—Surgical (ASERNIP-S) analyzed
Overview of bariatric surgery
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international data regarding LAGB and 55 papers evaluating VBG and RYGB.15 The reported 56% EWL at 4-year followup after LAGB was comparable with the long-term weight loss achieved with RYGB. In an observational cohort study, Christou and associates evaluated long-term morbidity and mortality in morbidly obese patients. They compared 1035 patients who underwent RYGB to 5746 age- and gender-matched morbidly obese controls who had non-surgical management of their weight. • The surgery group had a mean EWL of 67% at 5-year follow-up; >60% EWL at 16 years (72% follow-up); and significantly reduced risk of developing cardiovascular disease, cancer, infectious diseases, and endocrinologic, musculoskeletal, and respiratory disorders. • Five-year mortality in the bariatric surgery group was 0.68%, compared with 6.17% in the control group (89% relative risk reduction).16
Complications The risks of bariatric surgery have decreased with increasing experience and technical refinements. The operative mortality for restrictive procedures, gastric bypass, and BPD are 0.1%, 0.5%, and 1.1%, respectively. In the ASERNIP-S review, LAGB had an early mortality of 0.05%. Mortality after bariatric surgery is primarily due to pulmonary embolism and anastomotic leak. Early postoperative complications, particularly septic complications, are less common after restrictive procedures such as VBG and LAGB.
Vertical banded gastroplasty has largely been abandoned due to poor long-term weight loss and the late complications of gastroesophageal reflux, stomal stenosis, staple line dehiscence, and intractable vomiting. Patients with these complications frequently require conversion to a RYGB. Biliopancreatic diversion and duodenal switch procedures have excellent results in terms of short- and long-term weight loss and resolution of comorbidities, but these procedures have a higher mortality rate than other bariatric procedures and a higher incidence of metabolic and nutritional problems. Operative mortality for BPD ranges from 0.5 to 1.3%. Early postoperative complications include intraperitoneal bleeding, wound dehiscence, wound infection, anastomotic leak, and gastric perforation. Nutritional deficiencies can occur after bariatric procedures that bypass segments of the small bowel (BPD, duodenal switch, and RYGB). Table 1.3 summarizes the data from a review of nutritional deficiencies after bariatric procedures.17 Protein malnutrition is characterized clinically by hypoalbuminemia (<3.5g/dL), anemia, edema, and alopecia, and occurs 3–18% of the time after BPD or BPD-DS. These patients may require total parenteral nutrition, and 6% will have a revision to lengthen their common channel. Protein malnutrition is seen less frequently after standard RYGB (0–1.4%), but long-limb (>150cm) RYGB for superobese patients can result in protein deficiency 3–13% of the time and typically occurs within 2 years of surgery. Iron is absorbed in the duodenum and proximal jejunum, and iron deficiency after
1 Weight loss surgery: state of the art
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Table 1.3 Nutritional deficiencies after bariatric surgery
Deficiency Procedure Incidence (%) Range of follow-up (months)
Protein malnutrition BPD, BPD-DS 0–18 24–79 RYGB 0–13 12–43 Iron BPD, BPD-DS 23–44 28–48 RYGB 6–52 20–60 Vitamin B12 BPD, BPD-DS 22 48 RYGB 8–37 12–48 Folate – 22–63 12–24 Calcium Distal RYGB 10 24 BPD, BPD-DS 25–48 9–48 Vitamin D Distal RYGB 51 24 BPD, BPD-DS 17–63 9–48 Thiamine – < 1 3–5 Vitamin A Distal RYGB 10 48 BPD, BPD-DS 5–69 12–96 Vitamin E BPD, BPD/DS 5 28–48 Vitamin K BPD, BPD-DS 50–68a 23–48 Zinc BPD, BPD,DS 10–50 48 Magnesium BPD, BPD-DS 5 28 BPD, biliopancreatic diversion; BPD-DS, biliopancreatic diversion with duodenal switch; RYGB, Roux-en-Y gastric bypass. aNo increased clinical bleeding. (After Bloomberg et al. 2005,17 with permission.) bariatric surgery is seen most commonly after BPD and BPDDS (23–44%) and RYGB (6–52%). Vitamin B12 is absorbed in the terminal ileum, and deficiencies are seen after BPD (22%) and RYGB (8–37%). Calcium absorption (duodenum and jejunum) and vitamin D absorption (jejunum and ileum) are impaired after BPD and RYGB as well, and these deficiencies can lead to secondary hyperparathyroidism and increased bone resorption. Calcium deficiency occurs 10–48% of the time and vitamin D deficiency occurs 17–63% of the time in published studies of malabsorptive procedures.17 The absorption of fat-soluble vitamins is impaired after BPD due to the relatively short common channel. Routine vitamin and mineral supplementation and careful attention to protein intake following bariatric surgery are necessary. Serious complications of these deficiencies can generally be avoided by early recognition and increased oral supplementation. Further studies are needed to better define these deficiencies and to determine guidelines for supplementation. Hospital volume and surgeon experience are important factors in bariatric surgery outcomes. Nguyen and colleagues evaluated outcomes after RYGB according to hospital volume, and found higher morbidity and mortality rates for low-volume (<50 cases/year) compared with high-volume (>100 cases/year) centers (1.2% versus 0.3% mortality, respectively).18 Bariatric surgery, particularly the laparoscopic approach, is technically challenging surgery that involves a learning curve, and complications such as anastomotic leaks and internal hernias are more common earlier in a surgeon’s experience. Differences in complication rates between open and laparoscopic procedures are discussed later in this chapter.
BARIATRIC SURGICAL PROCEDURES
Vertical banded gastroplasty Vertical banded gastroplasty is a purely restrictive procedure that limits the amount of solid food that can be consumed at one time. A proximal gastric pouch empties through a fixed, calibrated stoma that is reinforced with an external silastic band or ring of mesh (Fig. 1.1). The advantages of VBG include:

• improvement of comorbidities after weight loss,

• minimal nutritional deficiencies,

• the absence of any gastrointestinal anastomosis, and

• a lower morbidity and mortality rate than with RYGB. It can be performed laparoscopically and is technically easier than RYGB. The disadvantages of this procedure include longterm weight loss that is inferior to that of RYGB, particularly in sweet eaters, and multiple long-term complications that frequently require reoperation.
Technique 1. A 32 French Ewald tube is passed into the stomach to size the pouch and stoma. 2. After the retrogastric dissection is completed from the gastrohepatic ligament to the angle of His, the anvil of an
EEA circular stapler is placed behind the stomach and manually passed through both walls of the stomach 8–9cm below the angle of His and adjacent to the Ewald tube. 3. The circular stapler is connected to the anvil and fired, creating a 2.5-cm window in the proximal stomach. Four rows of staples are then fired superiorly from the window to the angle of His to create a 50-mL pouch. 4. A 7 × 1.5cm strip of polypropylene mesh is then sewn to itself around the outlet channel. The laparoscopic approach has been used successfully for VBG. A linear-cutting stapler may be used to divide the vertical portion of the pouch or to excise a wedge of the fundus and eliminate the need for a circular stapler.
Efficacy Vertical banded gastroplasty achieves acceptable early weight loss but has less favorable long-term weight loss than other procedures used today. Ashy and colleagues demonstrated a weight loss advantage of open VBG (87% EWL) over LAGB (50% EWL) at 6 months.19 Some series have reported adequate long-term success with VBG, but EWL 3–5 years after VBG is typically 30–60%. Ten-year follow-up data show that only 26–40% of patients maintain acceptable weight loss (>50% EWL), and one-third of patients in these series returned to or exceeded their preoperative weight.20
Complications Early complications after VBG are infrequent, but late complications have resulted in a 17–30% reoperation rate. The most common late complications of VBG are:

• gastroesophageal reflux (16–38%), • stomal stenosis (20%),

• staple line disruption (11–48%), • incisional hernia (13%),

• band migration (1.5%), and • intractable vomiting (30–50%).21 Because of the poor long-term weight loss and high late complication rate, VBG has largely been abandoned and is performed by less than 5% of bariatric surgeons in the USA.
Laparoscopic adjustable gastric banding The LAGB is a restrictive procedure, and the device (LapBand; Inamed Corporation, Carpinteria, California) was approved for use in the USA in 2001, after having very good results in Europe and Australia. This silicone band with an inflatable inner collar is placed around the upper portion of the stomach to create a small gastric pouch. The band is connected to a port that is placed in the subcutaneous tissue of the abdominal wall. The inner diameter of the band can be adjusted by injecting saline through the port (Fig. 1.2).

• The adjustable nature of the LAGB is a major advantage that distinguishes it from VBG. Band adjustments are made according to weight loss.

• The LAGB is technically the simplest bariatric surgery to perform and requires less operating time than for other procedures.
Bariatric surgical procedures
7
• No anastomoses are created, and the morbidity and mortality are low.

• This procedure is reversible and, if patients fail to lose adequate weight after LAGB, it can be converted to a RYGB. The disadvantages of the LAGB include:

• the need for frequent postoperative visits for band adjustments, and

• band slippage or gastric prolapse through the band (5–10%). These mechanical complications require reoperation. Band erosion into the stomach, gastroesophageal reflux, esophageal dilatation, and dysmotility can also occur.
Technique

1. The patient is placed in steep reverse Trendelburg position, and six laparoscopic ports are placed.

2. The left lobe of the liver is retracted anteriorly, and a 15-mL balloon is placed transorally to calibrate the gastric pouch.

3. The pars flaccida technique is used to create a retrogastric tunnel from the base of the right crus of the diaphragm to the angle of His.

4. The band is passed through the retrogastric tunnel toward the angle of His and encircles the stomach approximately 1cm below the gastroesophageal junction.

5. The tail of the band is passed through the buckle, and the band is locked in place around the gastric cardia.

6. A calibration tube is passed to assess the size of the stoma, and the anterior stomach is sutured over the band with interrupted sutures. 7. The tube attached to the band is brought out through a left-sided trocar site and attached to the port.

8. The port is then placed in a subcutaneous pocket and sutured to the anterior rectus sheath. Patients remain in the hospital for 1 or 2 days, and a Gastrografin swallow is done prior to discharge to confirm band position and patency. Patients are kept on a liquid diet for 1 month postoperatively, at which time solid food can be introduced. Band adjustments can be made with or without fluoroscopic guidance. The first band adjustment is performed 4–8 weeks postoperatively, and patients are then observed monthly for the first year to assess weight loss and to make further adjustments if necessary.
Efficacy Reports of weight loss after LAGB have been variable but generally fall in the 40–55% EWL range 3 years after the procedure. Weight loss after LAGB is more gradual than with RYGB, and most of the weight loss after LAGB takes place in the first 3 years after surgery. O’Brien reported results on 706 patients undergoing the LAGB in Australia, with a mean EWL of 57% at 72 months and major improvements in diabetes, asthma, gastroesophageal reflux, dyslipidemia, sleep apnea, depression, and quality of life.22 The Italian Collaborative Study Group for the Lap-Band system reviewed 1863 patients
undergoing LAGB. Six-year follow-up showed a steady decrease in BMI from a preoperative average of 43kg/m2 to a BMI of 32kg/m2 at 72 months.23 Initial results with the LAGB in the USA were not as favorable as those in Europe and Australia. EWL at 2-year followup was typically reported to be between 35 and 45%. Some recent US studies of LAGB have approached the success rates seen in international studies, though, including a report of 1014 Lap-Band procedures with 64% EWL at 4 years (>85% follow-up). In this study, 75% of patients achieved satisfactory weight loss (>50% EWL) at 4 years.24
Complications Laparoscopic adjustable gastric banding has a low operative mortality (0.05%) and an 11% rate of perioperative and late complications.15 Postoperative mortality was 0.53% in the Italian Collaborative Study, and the ASERNIP-S review reported three deaths in 5827 LAGB cases (0.05%). Intraoperative bleeding or injury to the stomach, esophagus, or spleen occurs less than 1% of the time.

• Early postoperative complications include bleeding (0.5%), wound infection (0–1%), and food intolerance (0–11%).

• Late complications include band slippage or gastric prolapse through the band (7–21%), band erosion (2–7%), tube-related problems (4%), persistent vomiting (13%), pouch dilatation (5%), and gastroesophageal reflux. In a study of 1120 patients, O’Brien and Dixon reported a 1.5% early major complication rate.25 These complications included 10 access port infections; four patients with delayed emptying through the band; and one case each of deep venous thrombosis, hepatotoxicity, and bile leak from the liver. The most common late complication requiring reoperation after LAGB is gastric prolapse or slippage. As experience was gained, the rate of this complication decreased from 25% to 4.7%. Erosion of the band into the stomach occurred in 3% of patients early in the authors’ experience, and problems with the access port occurred in 5.4% of their patients. Although esophageal dilatation was common after prolapse or aggressive band adjustments, no persistent esophageal dilatation or dysmotility was found after appropriate treatment of the prolapse or decreased band restriction.
Roux-en-Y gastric bypass Roux-en-Y gastric bypass combines a restrictive and a malabsorptive procedure, and is the most commonly performed bariatric procedure in the USA (80%). A small 15- to 30-mL gastric pouch is created to restrict food intake, and a Rouxen-Y gastrojejunostomy provides the malabsorptive component (Fig. 1.4). The advantages of RYGB include:

• superior weight loss when compared with VBG,

• excellent long-term reduction in EWL, and

• resolution or elimination of comorbidities. Early and late complication rates are reasonably low, and operative mortality ranges from 0 to 0.5%. Dumping syndrome
1 Weight loss surgery: state of the art
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may occur after RYGB, and this may discourage patients from eating sweets. Disadvantages of RYGB include: • the potential for anastomotic leaks and strictures, • severe dumping syndrome symptoms, and

• procedure-specific complications including distension of the excluded stomach and internal hernias. The RYGB is technically more challenging to perform than the restrictive procedures, particularly using the laparoscopic approach.
Open RYGB technique 1. The abdomen is entered through an upper midline incision, and a thorough exploration is completed. 2. The anterior and lateral phrenoesophageal ligament is opened to the angle of His. 3. The distal esophagus is mobilized and encircled with a Penrose drain, and the gastrohepatic ligament is opened over the caudate lobe. 4. The mesentery between the second and third branches of the left gastric artery is divided, and a retrogastric space is developed from the lesser curvature to the angle of His. 5. The pouch can be formed using a series of firings with a linear-cutting stapler to create a vertically oriented pouch, or a red rubber tube placed in the retrogastric space can be used to guide 90-mm linear staplers behind the stomach to create a 15- to 30-mL pouch. 6. The ligament of Treitz is identified, and the jejunum is divided with a linear stapler 15–45cm distal to the ligament. 7. A standard length (75cm) or long-limb length (150cm for BMI >50kg/m2) Roux limb is measured, and the jejunojejunostomy is created with the linear stapler. 8. The mesenteric defect at the jejunojejunostomy is closed with suture. 9. The Roux limb can be brought up to the gastric pouch retrocolic and retrogastric, retrocolic and antegastric, or antecolic and antegastric, depending on the surgeon’s preference and tension on the Roux limb. If the Roux limb is brought through the transverse mesocolon, the space between the jejunal and transverse colon mesenteries is closed (Peterson’s space) to prevent internal herniation of small bowel. 10. A 1- to 1.5-cm gastrojejunostomy is either hand-sewn over a 30-F dilator or created with a circular stapler. 11. The anastomosis is tested with air insufflation or injection of methylene blue through a carefully guided nasogastric tube or with intraoperative endoscopy.
Laparoscopic RYGB technique 1. After pneumoperitoneum is established, five or six access ports are placed. 2. The sequential firings of a linear cutting stapler are used to create a vertically oriented gastric pouch measuring 15–30mL.

The ligament of Treitz is identified, and the jejunum is divided 10–12cm distally with a linear stapler. 4. A 75- to 150-cm Roux limb is measured, and a side-to-side jejunojejunostomy is created with a linear stapler. Several techniques can be used to create the gastrojejunal anastomosis. If a circular stapler is used, the anvil can be pulled into the pouch transorally using endoscopy and placement of a loop wire percutaneously into the gastric pouch. In the transgastric method, the anvil is placed in the stomach through a distal gastrotomy prior to pouch formation. The anvil is then positioned in the upper stomach and included in the pouch that is created with a linear stapler. The current method favored by the authors is placement of continuous layer of sutures to approximate the Roux limb and pouch, followed by the creation of a side-toside anastomosis with a linear stapler. 5. The anastomosis is completed with two layers of running suture anteriorly over a flexible endoscope. The anastomosis can also be completely hand-sewn in two layers. 6. The anastomosis is tested for integrity and hemostasis with the flexible endoscope. The conversion rate to open RYGB is <5%. Efficacy The RYGB results in mean EWL ranging from 65 to 80% in studies with follow-up of 2 years or less. There is no significant difference in weight loss between the open and laparoscopic approach, and weight loss typically reaches a nadir 18–24 months after surgery. In a study by Schauer and colleagues, the mean EWL was 83% at 1 year and 77% at 30 months.26 Longer follow-up after RYGB reveals some weight regain, with 60–70% EWL at 5 years. The Swedish Obese Subjects Study demonstrated 10-year weight loss (as a percentage of initial body weight) of 25% for RYGB.13 Nguyen and colleagues compared laparoscopic (n=79) to open (n=76) RYGB and found a longer operative time but shorter hospital stay (3 versus 4 days) in the laparoscopic group. Weight loss at 1 year was similar between groups, but the laparoscopic group had fewer wound complications and a more rapid return to daily activities.27 The RYGB results in significant improvement or resolution of many major obesity-related comorbidities (Table 1.4). Degenerative joint disease, hyperlipidemia, gastroesophageal reflux, hypertension, obstructive sleep apnea, depression, stress urinary incontinence, asthma, migraine headaches, venous insufficiency, congestive heart failure, and diabetes improve or resolve in the majority of patients after surgery. Type 2 diabetes resolves in over 80% of patients after RYGB. Complications Overall, the incidence of major early postoperative complications is similar between open and laparoscopic RYGB (10–15%). Notable exceptions to this, though, are the higher Bariatric surgical procedures 9 rate of anastomotic leak rate (1–5%) and internal hernias with the laparoscopic approach. Anastomotic leak rates decrease as a surgeon gains experience with the laparoscopic technique. The higher incidence of internal hernia may be due to a combination of technical factors, surgeon experience, and the formation of fewer intraabdominal adhesions following laparoscopic surgery. Pulmonary embolism occurs in 1–2% of patients after RYGB. Late complications after RYGB include anastomotic stricture (3–10%) and marginal ulcers (3–10%). Vitamin and nutritional deficiencies can be prevented or corrected with supplementation. Complications after open RYGB (n=2771, 8 series) and laparoscopic RYGB (n=3464, 10 series) were reviewed by Podnos and colleagues.28

• There were five intraoperative spleen injuries requiring splenectomy in the open cases, and none in the laparoscopic reports.

• The anastomotic leak rate was 1.68% for open RYGB and 2.05% for laparoscopic RYGB (not significant).

• Gastrointestinal tract hemorrhage was higher in the laparoscopic group (1.93% versus 0.60%, P=0.008), but wound infections and death occurred more frequently after open RYGB than after laparoscopic RYGB (6.63% versus 2.98%, P<0.001, and 0.87% versus 0.23%, P=0.001, respectively).

• There was no significant difference in rates of postoperative pneumonia (0.33%, open; 0.14%, laparoscopic).

• Late complications for open and laparoscopic RYGB included bowel obstruction (2.11% versus 3.15%, P=0.02), incisional hernia (8.58% versus 0.47%, P<0.001), and stomal stenosis (0.67% versus 4.73%, P<0.001). There is clearly a higher wound complication rate with open RYGB, and this was demonstrated in Nguyen’s randomized, controlled trial of laparoscopic versus open RYGB as well, with a wound infection rate and hernia rate of 7.9% each in the open group. This study also showed less pulmonary impairment during the first 3 postoperative days for the laparoscopic group.27 Biliopancreatic diversion Biliopancreatic diversion is a malabsorptive procedure developed by Scopinaro. The procedure consists of a distal gastrectomy and the creation of a long Roux-en-Y limb and an enteroenterostomy 50–100cm from the ileocecal valve to form the common channel. A modification of BPD with a duodenal switch (BPD-DS) consists of a sleeve gastrectomy and duodenoileostomy with a long alimentary limb and a common channel measuring 50–100cm (Fig. 1.3). The BPD-DS was developed to reduce the incidence of marginal ulceration, diarrhea, dumping syndrome, and protein calorie malnutrition seen with BPD. These procedures are primarily designed to limit intestinal energy absorption. Initial weight loss relies on decreased stomach capacity and rapid delivery of nutrients to the hindgut to limit appetite. Patients eventually regain their appetite and eating capacity, though, and the long-term success of BPD and BPD-DS relies on malabsorption, which is determined by the length of the common channel. The advantages of BPD include:

• substantial, durable weight loss (>70% beyond 10 years); and

• resolution of many obesity-related comorbidities. After the initial adaptation period, patients can eventually consume more calories than are expended and not regain weight. This procedure may be more effective than RYGB or restrictive procedures for superobese patients, and can be used as a secondary procedure in patients who have failed to lose weight with gastric bypass or restrictive procedures. BPD-DS can be performed laparoscopically.
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Table 1.4 Changes in comorbidities after laparoscopic Roux-en-Y gastric bypass13
Comorbidity Aggravated (%) Unchanged (%) Improved (%) Resolved (%)
Diabetes 0 0 100 82 Sleep apnea 2 5 93 74 Gastroesophageal reflux disease 0 4 96 72 Gout 0 14 86 72 Hypertension 0 12 88 70 Hypercholesterolemia 0 4 96 63 Hypertriglyceridemia 0 14 86 57 Migraine headaches 0 14 86 57 Urinary incontinence 0 11 89 44 Degenerative joint disease/osteoarthritis 2 10 88 41 Peripheral edema 0 4 96 41 Anxiety 0 50 50 33 Asthma 6 12 82 13 Depression 8 37 55 8
(After Schauer et al. 2000,26 with permission.)
Disadvantages include:

• a higher operative mortality rate (1.1%) than with other bariatric procedures; and

• metabolic complications including vitamin, mineral, and protein deficiencies that occasionally require reoperation to lengthen the common channel. Liver disease and diarrhea occur with BPD and BPD-DS, although less frequently than was seen with jejunoileal bypass. After surgery, patients typically have four to six foul-smelling stools per day and flatulence as a result of fat malabsorption. Inability or unwillingness to comply with a strict nutritional supplementation regiment postoperatively is a contraindication to performing this procedure. BPD and BPD-DS, particularly if done laparoscopically, are technically challenging operations performed routinely only at specialized centers.
Technique Biliopancreatic diversion Biliopancreatic diversion consists of a subtotal gastrectomy leaving a proximal 200- or 400-mL pouch. The smaller pouch is used for superobese patients. 1. The small bowel is divided 250cm from the ileocecal valve, and the distal end is anastomosed to the gastric pouch with a 2- to 3-cm stoma. 2. A common channel is formed by completing the Roux-enY enteroenterostomy 50–100cm from the ileocecal valve. If present, the gallbladder is routinely removed at the time of BPD due to the high incidence of postoperative cholelithiasis.
Duodenal switch The duodenal switch consists of a greater curvature sleeve gastrectomy, leaving the antrum, the pylorus, and the first portion of the duodenum in continuity. The remaining gastric reservoir is 150–200mL. 1. The proximal duodenum is divided, and a duodenoileostomy is created using a 250cm long alimentary limb. 2. A Roux-en-Y anastomosis is then created to form a 100cm long common channel.
Efficacy Weight loss after BPD is excellent, and the results are durable. A recent metaanalysis demonstrated that BPD had a higher percentage of EWL (70%) than other bariatric procedures.14 Scopinaro reported overall EWL of 74% at 8 years and 77% at 18 years. There was no difference in long-term EWL between morbidly obese and superobese (>120% ideal body weight) subjects.29 Ren and colleagues performed 40 laparoscopic BPD-DS procedures and reported EWL of 58% at 9 months. Operative time and perioperative morbidity were higher in patients with BMI >65kg/m2.9
Complications Postoperative complication rates for BPD are relatively high, and postoperative mortality ranges from 0.4 to 1.3%. Marginal ulceration can occur up to 10% of the time, but this can
be reduced to 1–3% with the duodenal switch and acid suppression therapy. Other complications include:

• dumping syndrome;

• protein calorie malnutrition and anemia in up to 12% and 40% of patients, respectively;

• vitamin B12 deficiency; • hypocalcemia;

• fat-soluble vitamin deficiency; and

• bone demineralization (6%). Failure to screen for such problems can lead to an unfavorable wound healing after body-contouring surgery. The plastic surgeon reading this chapter should also be cognizant of the expected outcomes from these procedures in terms of magnitude of weight loss and effect on medical problems. A basic appreciation of how the specific procedures impact nutritional status is crucial. In Scopinaro’s series of over 1700 BPD patients, the overall rate of early major surgical complications (intraperitoneal bleeding, wound dehiscence, wound infection, anastomotic leak, and gastric perforation) decreased from 2.7% in his first 738 cases to 1.4% in his last 500 cases. Late complications of BPD included iron deficiency anemia, which was decreased to less than 5% with supplementation.

Other late complications included stomal ulcer in 3% of patients, incisional hernia (8.7%), and protein malnutrition (7%). Four percent of patients required elongation of the common channel or reversal of BPD. In Ren’s laparoscopic series, there was one death (2.5%). Postoperative complications included anastomotic leak (2.5%), venous thrombosis (2.5%), subphrenic abscess (2.5%), and staple line hemorrhage (10%), with an overall major morbidity rate of 15%.
CONCLUSION
Obesity is a major public health problem in developed countries worldwide. Currently, the only treatment for this disease that provides long-term weight loss is surgery. Restrictive, malabsorptive, and combination procedures have been developed, and each has its merits and unique set of risks and complications. Weight loss after bariatric surgery is accompanied by improvement or resolution of obesity-related comorbidities and improved life expectancy. Careful patient selection for bariatric surgery and selection of the appropriate procedure for each patient are keys to success when performing these operations. Close monitoring for nutritional deficiencies and short- and long-term complications is required to completely assess outcomes after these procedures.
REFERENCES

National Institutes of Health Conference. Gastrointestinal surgery for severe obesity. Ann Intern Med 1991; 115:956–961. 2. Hedley AA, Odgen CL, Johnson CL, et al. Overweight and obesity among US children, adolescents, and adults, 1999–2002. JAMA 2004; 291:2847–2850.
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