Bariatric Surgery in Adolescents

CHAPTER 80

Bariatric Surgery in Adolescents Sean Barnett, Victor F. Garcia, and Thomas H. Inge

Obesity is a progressive, chronic, and often fatal disease, refractory to most currently available medical interventions. The definition of overweight and obesity in children is a body mass index (BMI) greater than 85th and 95th percentile (P), respectively, for age and gender. In 2007-2008, 32% of children (2 to 19 years old) were at or above the 85th P, 17% were at or above the 95th P, and 12% were at or above the 97th P of the BMI-for-age. Trend analyses indicated that there was no significant increase in overweight or obesity prevalence between 1999-2000 and 2007-2008. However, prevalence of those at the highest (97th P) levels of obesity among 6- through 19-year-old boys and among non-Hispanic white boys of the same age was increasing. In 2007 the estimated prevalence of extreme pediatric obesity (BMI > 99th P) was 4%.1 Obesity-related decreases in life expectancy predominantly affect age groups younger than previously thought, especially in young black males.2 Childhood and adolescent obesity are independent risk factors for adult morbidity and premature mortality.3–4 In the extreme form, with BMI for age in the greater than 99th P, obesity is refractory to even the most intensive conventional approaches to weight loss.5–6 Bariatric surgery is currently the most effective means to achieve durable weight loss and amelioration, if not resolution, of most obesity-related comorbidities in severely obese individuals. It also decreases the

long-term mortality of morbidly obese patients.7–8 The morbidity of surgery varies between 5% and 11%. The mortality was recently estimated by the LABS study group to be 0.3 for gastric bypass procedures9; most studies demonstrate even lower mortality risk for adjustable gastric banding (AGB). Experienced centers have shown that weight loss following bariatric surgery in adults can be sustained.10 Among adults, the nutritional consequences of the most common bariatric surgical procedures are well defined and effectively managed with vitamin and mineral supplementation. Among adolescents, however, it is unknown whether the outcome will be the same as in adults or whether there will be unacceptably high degrees of recidivism and long-term nutritional sequelae related to poor compliance or reduced micronutrient absorption.11–13 Nonetheless, for the extremely obese adolescent there are currently no effective nonsurgical treatments.14 As the number of severely obese children increases and the serious health consequences escalate, surgical weight loss is becoming the only effective means to treat severely obese adolescents. On the basis of the best available evidence, this chapter proffers a conceptual framework and clinical guidelines for adolescent bariatric surgery. The approach borrows heavily from the most successful adult bariatric surgical programs and best practice guidelines. The unique physiologic, cognitive, developmental, and psychosocial needs of the adolescent are best managed with a family-centered, interdisciplinary approach, incorporating behavior modification techniques that have been successful in other chronic health care models. Given the technical difficulty of bariatric surgery, the complexity of the postoperative management of the patient undergoing bariatric surgery, and the extant uncertainty about its long-term outcomes in adolescents, regionalization of care with a focus on prospective clinical data collection will be essential to achieving outcomes commensurate with the best adult series. Further, it will accelerate our understanding of the short- and long-term consequences of bariatric surgery among adolescents.

History of Bariatric Surgery in Adolescents ------------------------------------------------------------------------------------------------------------------------------------------------

The earliest report of pediatric bariatric surgery was Randolph and Weintraub’s experience with jejunal ileal bypass.15 Their reported outcomes were similar to those in adults. More specifically, the weight loss was dramatic and sustained and the improvements in quality of life were viewed as excellent. However, the metabolic complications were significant15 and considered unacceptable by today’s standards. Greenstein16 reported a largely favorable experience with vertically banded gastroplasty, concluding that adolescents given extensive dietary counseling can experience the same benefits as adults. The subsequent reports of bariatric surgery in pediatrics have consisted of small case series of adolescents largely undergoing open and, more recently, laparoscopic Roux-en-Y gastric bypass surgery (RYGB) or laparoscopic AGB. As summarized in a recent systematic review, the reported outcomes have been good to excellent, with few complications and no procedure-related mortality.17 As with pediatric laparoscopic cholecystectomy, minimally invasive repair of pectus excavatum, and laparoscopic antireflux procedures, bariatric 1041

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operations among adolescents are only now beginning to be studied in a prospective and controlled fashion.18 None of the adolescents who have undergone AGB have been followed for more than 4 years. The only randomized controlled trial examined AGB compared with lifestyle intervention in a cohort of 50 Australian adolescents. In the gastric banding group (n ¼ 25, with 24 completing the 2-year study), a weight loss of 34.6 kg representing a BMI reduction of 28% (excess weight loss of 78.8%) was seen, compared with a 3-kg loss representing a BMI reduction of 3% (excess weight loss of 13.2%) in the lifestyle group. Health and quality of life improvements were also documented.19 However, eight operations (33%) were required in seven patients for revisional procedures either for proximal pouch dilatation or tubing injury during followup. This high rate of surgical complications is of considerable concern and is based primarily on symmetric pouch dilation, a problem infrequently seen in adults. It is likely that maladaptive eating behaviors rather than surgical technique contributed to this problem. Thus programs that focus on banding as a weight loss intervention for adolescents must consider how to best educate patients and families about postoperative dietary behaviors to address preventable complications. The report with the largest and longest follow-up is that of Sugerman and colleagues.13 These authors’ outcomes reported 33 adolescents (mean preoperative BMI ¼ 52 kg/m2) who underwent various bariatric procedures, primarily gastric bypass. This group had an excess weight loss of 63% (mean BMI ¼ 33 kg/m2) at 5 years and 56% (mean BMI ¼ 34 kg/m2) at 10 years after operation. Only six of nine patients who were 14 years following operation could be found. These six had maintained 33% of their excess weight loss (mean BMI ¼ 38); 15% of the cohort had regained most or all of their overweight, suggesting that recidivism may be just as likely in adolescents as in adults. These data beg several questions—whether adolescents require alternate selection criteria or different postoperative management strategies than adults and whether the long-term nutritional and metabolic outcomes of adolescents will be better or worse than similarly obese adolescents who have undergone bariatric surgery in youth. In 2001 the first children’s hospital–based bariatric surgery program was established at Cincinnati Children’s Hospital Medical Center.18 The bariatric surgery program was integrated into an existing behaviorally based weight management program for children and adolescents. This comprehensive program offers bariatric services to adolescents with intractable clinically severe obesity. Candidates for bariatric surgery are evaluated by pediatric bariatric surgeons, a pediatric psychologist, and other pediatric medical specialists with expertise in pediatric obesity; an advanced practice nurse; dieticians; and an exercise physiologist. Since that time, there have been few dedicated pediatric centers for the treatment of morbid obesity established. The vast majority of these patients are still treated in adult facilities. Our most recently published data analyzed 61 adolescents with a mean preoperative BMI of 60.2 kg/m2 who underwent laparoscopic Roux-en-Y gastric bypass from August 2002 to January 2007.20 The mean weight loss for this group was 37.4% one year postoperatively with statistically significant improvements in systolic and diastolic blood pressure, total cholesterol levels, triglyceride levels, and fasting insulin levels.20 Of the nine patients who were on medications for diabetes preoperatively, only one remained on medication postoperatively.20

Science of Obesity ------------------------------------------------------------------------------------------------------------------------------------------------

Obesity research is one of most exciting areas of scientific investigation at the nexus of physiology, genetics, neurobiology, endocrinology, molecular biology, and gastrointestinal surgery. Genes regulate body weight by balancing caloric intake and energy expenditure. Familial aggregation and twin studies have demonstrated that genes contribute to the development of obesity with a heritability index of 0.7 to 0.8, a degree of heritability equivalent to that of height.21–22 Only about 5% of childhood morbid obesity is a result of a single gene defect, usually in an isoform of the melanocortin receptor, the receptor for melanocyte stimulating hormone.23 In the remainder of the population, obesity is the result of many genes interacting with environmental factors. Evidence indicates that genes and metabolic processes that predispose to obesity offered our ancestors a survival advantage in times when food was scarce.24–25 This may explain the highly variable frequency of obesity in different populations (African Americans, Native Americans, and Hispanics) that once lived under adverse conditions.

Risk Factors for Adolescent Obesity ------------------------------------------------------------------------------------------------------------------------------------------------

The risk of obesity accumulates with age and is influenced by genetic, biologic, psychologic, socio-cultural, and environmental factors acting throughout our life span. Recent insights into the fetal, neonatal, and developmental origins of obesity26 have implications for clinical evaluation of the adolescent candidate for bariatric surgery. There are critical phases in the development of adolescent obesity within the period between preconception and adolescence.27–31 Epidemiologic evidence has linked birth weight and later body mass index32 in childhood33 and adulthood.34 Lower birth weight elevates the risk for central obesity33,35 and insulin resistance.35 Childhood obesity risks are higher for offspring of mothers with diabetes mellitus.36 Postnatally, longer duration of breastfeeding37–38 and later onset of adiposity rebound39 reduce the risk of adolescent overweight. Of all the aforementioned risk factors, low birth weight and high BMI of the adolescent confer the highest risk of chronic obesity. Obesity in family members is an additional risk factor for adolescent obesity. The odds ratio for persistence of childhood obesity into adulthood is about 3 if one or 10 if two parents are obese.40 This effect is most pronounced in children younger than 10 years. Puberty is also a critical period for the development of obesity.41 Earlier menarche is seen in obese children. A BMI greater than the 85th P is associated with a twofold increase in rate of early menarche.42–43 The risk of obesity persisting into adulthood is far higher among obese adolescents than among overweight younger children.1,6 Finally, there is a preexisting racial-ethnic disparity in the risk of obesity.44 Lower socioeconomic groups may be especially vulnerable because of poor diet and limited opportunity for physical activity.45

HEALTH CONSEQUENCES OF ADOLESCENT OBESITY Adolescent obesity has important health consequences as outlined in Table 80-1. Associated with the rise in the prevalence and severity of pediatric obesity in the United States, there has

CHAPTER 80 TABLE 80-1 Health Consequences of Pediatric Obesity Complications of Adolescent Obesity Psychosocial Poor self-esteem85–87,164 86–88,165–166 Depression Eating disorders167–168 Attention deficit hyperactivity disorder169 Neurologic Pseudotumor cerebri170–172 Pulmonary Sleep apnea77,173–175 Asthma and exercise intolerance176–177 Cardiovascular Dyslipidemia61,114,178–179 Hypertension92,180–182 Coagulopathy, chronic inflammation183 Endothelial dysfunction184–187 Gastrointestinal Gallstones Steatohepatitis67,72,188 Gastroesophageal reflux disease189 Renal Glomerulosclerosis190–191 Endocrine Type 2 diabetes mellitus,65,91,192–195 Insulin resistance33,65,92–93,196–198 Metabolic syndrome53,55,93,199–200 Precocious puberty50,201 Polycystic ovary syndrome95,202 Musculoskeletal Slipped capital femoral epiphysis, Blount disease203 Forearm fractures, flat feet

been an emergence of new or newly identifiable health conditions in children46 with onset at a younger age47–48 and an increased risk for adult morbidity and mortality.47 Childhood obesity also has adverse social and economic consequences.49–50 The persistence of obesity,51 with approximately 70% to 80% of overweight children becoming obese adults,1,46 is of particular concern for certain complications. The clustering of hypertension, dyslipidemia, chronic inflammation, hypercoagulability, endothelial dysfunction, and hyperinsulinemia, known as insulin resistance syndrome or metabolic syndrome,52 has been identified in children as young as 5 years of age.53 The Bogalusa Heart Study noted the correlation of cardiovascular disease risk factors with asymptomatic coronary atherosclerosis. The more severely obese individuals had more advanced lesions.54 The metabolic syndrome is far more common among children and adolescents than previously reported, and its prevalence increases directly with the degree of obesity.55 Each element of the syndrome worsens with increasing obesity, independent of age, gender, and pubertal status. A prediabetic state, consisting of glucose intolerance and insulin resistance, is highly prevalent among severely obese children, even before clinical diabetes has been diagnosed.56 Even though formerly considered an “adult-onset” disease, type 2 diabetes mellitus now accounts for nearly half of all new pediatric diagnoses of diabetes57–58 and is thought to

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be largely the result of the pediatric obesity epidemic. Of particular concern are data from the Centers for Disease Control suggesting that 33% of all Americans born in the year 2001 will develop diabetes.59 For blacks and Hispanics this number rises to nearly 50%.59 The data suggest that the onset of the beta cell dysfunction associated with diabetes occurs well before the development of hyperglycemia and may commence many years before diagnosis of the disease.60–63 Other work clearly suggests that type 2 diabetes developing in childhood or early adulthood progresses much more rapidly than in adults64 and may be more virulent than diabetes that develops later in adulthood. Bariatric surgery in adolescents, particularly gastric bypass, has been shown to completely resolve type 2 diabetes following significant weight loss.65 Given these findings and the progressive nature of the disease, established type 2 diabetes mellitus is a strong indication for weight loss surgery in adolescents.66 Nonalcoholic steatohepatitis is recognized as a common cause of chronic liver disease in children.67 This condition is frequently associated with obesity, with 25% of overweight children in one report having abnormally elevated liver function tests.68 It has been suggested that obesity-related pediatric nonalcoholic steatohepatitis69 may become a major cause of hepatic failure and a leading indication for liver transplantation in decades to come.67,70–72 Bariatric surgery has been shown to decrease not only the amount of steatosis73 but also the associated inflammatory markers.74 Currently weight loss is the only treatment for severe steatosis and is considered a strong indication for bariatric surgery.66 Exercise intolerance, sleep-disordered breathing, and asthma are frequent pulmonary complications of adolescent obesity.75–77 Asthma and exercise intolerance can also limit physical activity and contribute to further increases in weight.78 Obstructive sleep apnea (OSA), the most severe manifestation of sleep-disordered breathing, can significantly impair the obese adolescent’s health-related quality of life,77,79 result in abnormal left ventricular geometry,80 and put him or her at increased risk for hyperactivity and learning difficulties.81 Although up to 20% of adolescents with obesity have moderate to severe OSA, those presenting for bariatric surgery have a prevalence of greater than 50%.82 Within our institution using polysomnography, OSA significantly improves or resolves completely in adolescents undergoing gastric bypass.77 Therefore moderate to severe OSA is a strong indication for early bariatric surgery in adolescents.66 Pseudotumor cerebri is a process for which the major symptoms include headache, dizziness, nausea, tinnitus, and blurry vision due to increased intracranial pressure caused by morbid obesity. The treatment of choice has long been bariatric surgery,83 and these symptoms can improve over the course of months following surgery in adolescents.84 Arguably the most prevalent and debilitating consequences of adolescent obesity are psychosocial.85–88 The psychologic stress of social stigmatization imposed on obese children may be as damaging as the medical morbidities.89 Many obese adolescents have low self-esteem associated with sadness and high-risk behaviors.85 In a recent inventory of health-related quality of life (QOL) indices, obese adolescents demonstrated significantly lower QOL scores than lean children and scores that were comparable with pediatric cancer patients.79 Overweight has also been associated with lower levels of socioeconomic attainment. Women who were overweight adolescents

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were less likely to marry and had completed fewer years of school.90 A recent longitudinal prospective study demonstrated a significant improvement in depressive symptoms and quality of life over the first postoperative year following bariatric surgery in adolescents.87 The health consequences of childhood obesity are broader in scope, greater in prevalence, and more severe at a given time point in disease progression than previously thought.91–96 BMI thresholds for obesity do not account for the ethnic disparity of disease burden nor the accelerated progression of disease in certain populations of obese adolescents.94,97–98 The progressively younger age at which adult diseases are recognized in children;53,99 the increasing prevalence of impaired glucose tolerance, insulin resistance, metabolic syndrome, and type 2 diabetes mellitus in younger children;53,56,100–102 and the suggestion that childhood-onset type 2 diabetes mellitus may be more virulent than adult-onset diabetes validates concerns about the clinical relevance of the current definitions of obesity in children and about disease burden over time affecting the ability to control these comorbidities.103–105 Longitudinal studies performed at our institution assessing the characteristics of 61 adolescents undergoing gastric bypass demonstrated a mean baseline BMI of 60.2 kg/m2. At 1-year follow-up, the cohort had experienced a BMI reduction of 37%, but only 17% achieved a nonobese BMI of less than 30 kg/m2. Of note, those adolescents with a baseline BMI above 65 kg/m2 reached a nadir BMI still in the morbidly obese range (47 kg/m2) at 1 year, suggesting that “late” referral at the highest BMI values all but eliminates the chances of attaining a nonmorbidly obese BMI after the most intensive of treatments.20 One could argue that earlier referral, with BMI values in the 35 to 50 range should be the goal to optimize treatment outcomes in adolescents.

Adolescent Cognitive Development: Concepts and Principles Relevant to Adolescent Bariatric Surgery ------------------------------------------------------------------------------------------------------------------------------------------------

Cognitive development refers to the development of the ability to think and reason. Around 6 to 12 years of age, children develop the ability to think concretely. Adolescence marks the beginning of more complex thinking. At any given age, adolescents are at varying stages of cognitive and psychosocial development, which more closely correlates with pubertal status than with chronologic age.106 Additionally, there are gender differences in the attainment of formal operations and identity formation enabling new levels of intellectual functioning, abstract thinking, and cognitive skills, which are critical to providing assent to, and complying with, medical recommendations. Examples of formal operations include thinking about possibilities, hypothetical-deductive reasoning, anticipating events that have not yet happened, thinking about conventional limits, and thinking about thought. Before the attainment of formal operations, the adolescent functions and reasons in concrete operations. At this stage of development, adolescent problem solving is confined to identifiable objects that are either directly perceived or imagined and mental operations are only possible when they are applied

to information from the direct experience. In acquiring formal operations, the adolescent has the ability to reason, think abstractly and logically, form hypotheses, and consider various consequences of behavior. The adolescent who has acquired this ability is better able to consider the consequences of taking or not taking nutritional supplements or of following and adhering to the prescribed protein-sparing diet. Adolescence is also generally regarded as a period of social experimentation, limit-testing, risk taking, and egocentrism—all of which predictably add to the challenge of adolescent compliance with desired health behaviors. The postoperative management of the adolescent bariatric patient requires an assessment of the level of cognitive development and an understanding of the risk-taking propensity of adolescents.107 It is also important to note that the level of cognitive sophistication differs from adolescent to adolescent and may be independent of chronologic age.108 The attainment of new mental abilities does not carry with it immediate proficiency in their use, nor does education alone enhance cognitive maturity. Enhanced compliance with a vigorous nutritional and lifestyle regimen requires effective education that applies cognitive development theory and also input from peers and family that helps the adolescent attain a more realistic appreciation of their own vulnerability.

COMPLIANCE Long-term therapeutic success with bariatric surgery is dependent on compliance with the prescribed dietary, lifestyle, and nutritional supplement regimen. Adolescence is generally viewed as a time of increased experimentation with a variety of health-related behaviors such as diet and exercise. Expertise with enhancing adherence to preventive health practices and compliance with treatment regimens is critical. Historically, compliance with health recommendations in the adolescent population is disappointingly low, estimated at 40% to 50% for adolescents with chronic medical conditions such as cystic fibrosis, diabetes, and asthma.109 Rand and McGregor found that after bariatric surgery, less than 20% of adolescents demonstrated perfect compliance with vitamin and mineral supplementation regimens.11 For adolescents with chronic medical conditions, adherence with rigorous medical and dietary regimens is substantially improved with use of behavioral therapy.110–115 Unfortunately, there is no clear profile of the psychosocial factors consistently associated with the compliant patient, thus precluding a “cookbook” solution for the prevention and management of poor compliance in the adolescent who has undergone bariatric surgery. To enhance adolescent compliance with a lifelong postoperative dietary and nutritional supplement regimen, an adolescent bariatric surgery program should employ professionals capable of assessing levels of cognitive development, personality characteristics such as self-esteem and locus of control, as well as family variables such as cohesiveness and level of effective communication.108 Prior knowledge of these factors may enhance the ability of the bariatric team and the primary care physician to offer useful anticipatory guidance postoperatively. For example, it can be useful to know when and with whom most nonnutritive calories are consumed so that the team is aware of the periods/people that may increase the adolescent’s vulnerability to maladaptive postoperative eating habits. Adolescent compliance may be enhanced by

CHAPTER 80 TABLE 80-2 Strategies to Improve Postoperative Compliance • Dietary regimen rehearsal preoperatively enables problem identification and solving before the surgical intervention. • Use of actual measuring cups, a food scale, and photographs of specific food items that are recommended enhances the adolescent’s ability to follow through with plans. • Provide the adolescent with a diet diary and exercise diary with form pages for him or her to fill out, and practice this preoperatively. • Provide a list of acceptable food items for every phase of the postoperative recovery (first week, second through fourth week, second through third month, etc.) including the caloric density and protein, carbohydrate, and fat content of the items to encourage label reading. • Provide a detailed listing of micronutritional supplements needed postoperatively that includes the reason why the supplement is necessary, as well as the potential consequences of not taking it.

(1) visual aids, (2) focus on immediate benefit from treatment, (3) participation in self-management, (4) self-monitoring, and (5) self-reinforcement.116 Adolescent self-management and related strategies encourage independence from the family, an important developmental task of adolescence. With the alterations in eating patterns that are required after bariatric surgery, repetitive reinforcement is necessary to facilitate the formation of lifelong health-promoting habits. Patients and their families may require counseling and close follow-up to promote their physical and emotional well-being. The adolescent bariatric surgery program should build on the best practices of other adolescent disease management programs111,117–118 and thus be based on the premise that sustained weight control for the adolescent requires structured family involvement and continued support. Specific strategies to increase adolescent compliance include education, treatment regimen modification within the socialcultural context of the patient, and enlisting family and peer support108 (Table 80-2). Some adolescents respond to formalized modes of reinforcement such as contracting.

Bariatric Surgery ------------------------------------------------------------------------------------------------------------------------------------------------

Bariatric surgery should be viewed as a surgical discipline and not just a technical procedure. Bariatric patients are a distinct and often problematic cohort with serious and often multiple concurrent comorbidities. They have unique postoperative needs and in the event of postoperative complications conventional diagnostic approaches often do not work. They require close long-term follow-up making the transition of the adolescent who undergoes bariatric surgery to adult care an essential component of the clinical care plan.

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The majority of bariatric surgery is now performed laparoscopically. Minimally invasive bariatric surgery has significant advantages over open surgery but is one of the most technically difficult operations to perform.119 The learning curve is steep.8 Schauer suggests the curve levels off at 100 operations.120 Laparoscopic skills employed in foregut surgery are not directly transferable to bariatric surgery, and proficiency in minimally invasive surgery may not confer the same level of proficiency in minimally invasive bariatric surgery. Several societies and associations have developed credentialing criteria and guidelines for bariatric surgery, and most recently the American Society for Bariatric Surgery has introduced criteria for Centers of Excellence in Bariatric Surgery. Pediatric surgeons pursuing bariatric surgery should at a minimum take a course in bariatric surgery and have their early experience proctored by an experienced laparoscopic bariatric surgeon. Additionally, they must be cognizant of and take into account, during patient selection, patient characteristics that are recognized as risk factors for perioperative complications and mortality.121–125 Recent data demonstrate the mean BMI of patients undergoing gastric bypass at our institution is 60.2 kg/m2.20 Adult studies of patients with BMI greater than 60 kg/m2, coined the super-super obese, have shown longer procedure times and longer hospital stay.126 The pediatric bariatric surgeon must also be prepared for these more difficult patients early in their learning curve given current referral patterns.

Surgical Options ------------------------------------------------------------------------------------------------------------------------------------------------

There are five bariatric procedures in general use: RYGB; laparoscopic AGB; vertical banded gastroplasty; biliopancreatic diversion (BPD), with or without duodenal switch (DS); and the laparoscopic sleeve gastrectomy. Each has its unique profile of potential complications and nutritional concerns.127 All of these operations can achieve significant weight loss with improvement or reversal of obesity comorbidities. Each can be performed laparoscopically, which may result in shorter length of hospital stay, shorter convalescence,122,128–129 and decreased risk of wound complications. Attempts to determine what patient features might predict which particular operation might be best suited to an individual’s needs are ongoing, but none have been prospectively evaluated.130 For the most part, vertical banded gastroplasty is of historical interest and is not addressed further. Table 80-3 outlines the percent of excess weight loss, associated morbidity and mortality, and whether the operations can be revised or reversed.

TABLE 80-3 Comparison of Bariatric Procedures Procedure

Weight Loss % EBW

Mortality %

Morbidity %

Can Be Reversed

Can Be Revised

Durability of Weight Loss

RYGBP LAGB LSG BPD  DS

65-70 47 33-83 70

0.5 0.1 0.39 1.5

5 5 0-20 5

Yes Yes No Yes

Yes Yes Yes Yes

þþþþ ? ? þþþþ

BPD  DS, biliopancreatic diversion with or without duodenal switch; EBW, excess body weight; LAGB, laparoscopic adjustable gastric band; LSG, laparoscopic sleeve gastrectomy; RYGBP, Roux-en-Y gastric bypass.

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Roux-En-Y Gastric Bypass Gastric bypass is chiefly a restrictive procedure that modifies normal appetite signals and is modestly malabsorptive as well. It is the first of the gastric procedures and the most common bariatric procedure performed in the United States. The restrictive component is a small gastric pouch (15 to 20 mL) with a small gastric outlet (1 to 2 cm) that results in early and sustained satiety. Intestinal continuity is reestablished with a gastrointestinal bypass of varying segments of bowel—standard, 75 cm; long limb, 150 cm; and very long limb or distal gastric bypass, 250 cm.119 The limb can be positioned retro-colic or ante-colic and the gastrojejunal anastomosis can be fashioned with an end-to-end stapler or linear stapler, or it can be hand sewn.119 See Figure 80-1. Currently a 25-mm, end-to-end, circularly stapled gastrojejunostomy with an antecolic or retrocolic reconstruction is commonly performed. In patients with BMI greater than 50 kg/m2 the longer limb bypasses result in weight loss comparable with that of standard gastric bypass in less obese patients. Weight loss (30% to 40% of preoperative weight) occurs over 1 to 2 years, followed by a plateau and then gradual regain of 5% to 10%. Complications include dumping syndrome, gastrojejunal stomal stenosis, marginal ulcers, and internal hernias. This operation has been studied for more than 14 years and results in durable weight loss over this period of time.10

Laparoscopic Adjustable Gastric Banding ------------------------------------------------------------------------------------------------------------------------------------------------

The AGB procedure is the least invasive bariatric procedure and the most common procedure performed in Europe, Latin America, and Australia. The U.S. Food and Drug Administration (FDA) approved the Lap Band for use in adults in 2001 and the Realize Band in 2007. Their use and acceptance in this country is increasing. The laparoscopically placed band creates a small pouch and a small stoma high on the stomach. A port for adjustment of the band is placed in the anterior abdominal wall. Periodic adjustments of the band are critical for a successful outcome, requiring from 4 to 10 visits within the first postoperative year. Complications of the Lap Band include gastric prolapse, stomal obstruction, erosion of the band into the stomach, and problems with the access port. The pars flaccida technique has significantly reduced the risk of gastric prolapse.131 Average weight loss after 3 years is approximately 25% to 30% of the baseline weight.121 The LAGB is currently being used within the context of an investigational device exemption from the FDA in adolescents younger than 18 years at several U.S. centers. Results of the trial are still pending.

Biliopancreatic Diversion/ Duodenal Switch ------------------------------------------------------------------------------------------------------------------------------------------------

BPD132 is widely used in Europe. The DS is a modification developed by Hess and colleagues.133 Both are primarily malabsorptive operations involving the creation of a 100- to 150-mL gastric pouch. By dividing the intestine into a long enteric limb anastomosed to a long biliopancreatic limb, a common channel 50 to 150 cm from the ileocecal valve is created and toxic

problems seen with jejuno-ileal bypass are avoided. The weight loss is greater with BPD/DS than with the other weight loss procedures. However, the vitamin, nutrient, and protein deficiencies are more common with these procedures than with the aforementioned bariatric procedures.134–135 Given the well-described compliance issues among adolescents and the aforementioned protein and vitamin deficiencies, the risks of the surgery outweigh the benefits and are not recommended in adolescents.66 Laparoscopic Sleeve Gastrectomy Laparoscopic sleeve gastrectomy (LGS) has long been used as part of the larger biliopancreatic diversion/duodenal switch (BPD/DS) or as a bridge to BPD/DS in the super-obese patient. This restrictive procedure involves the longitudinal resection of the stomach along a narrow 32- to 34-Fr bougie, although some have used larger bougie sizes. The resection extends from roughly 6 cm from the pylorus to the angle of His, thus creating a long gastric tube along the lesser curve. The fundus and greater curvature of the stomach are removed. The mechanism of weight loss is not yet understood but may be the result of both restriction and alteration of appetite and satiety signals from the gut to the brain including changes in ghrelin and PYY levels.136 Excess weight loss ranging from 33% to 83% have been reported with the longest follow-up of only 3 years.137 Complication rates range from 0% to 24% with an overall reported mortality rate of 0.39%.137 Long-term data have not been reported for sleeve gastrectomy at this time, and the lack of these data should be discussed with the patient before the operation. Laparoscopic sleeve gastrectomy does involve much less anatomic and physiologic derangement than that of RYGB and is an intriguing alternative in the adolescent patient population. We have currently performed 14 laparoscopic sleeve gastrectomies at our institution and in our early experience have found similar weight loss compared with our patients undergoing RYGB. Long-term data are still necessary to determine whether LGS is a durable alternative or will require conversion to RYGB at a later date in some patients.

New Procedures ------------------------------------------------------------------------------------------------------------------------------------------------

A number of new concepts/procedures are being developed for use in the bariatric arena including the intragastric balloon, vagal and gastric stimulators, greater curve gastric plication, Endosleeve bypass, and new endoscopic techniques.138 Although none of these is currently FDA approved in the United States, they among others are certainly on the horizon for the surgical treatment of obesity.

NUTRITIONAL AND METABOLIC CONSEQUENCES Nutritional and metabolic consequences of bariatric surgery have been well-delineated.139–144 There is impaired absorption of iron, folate, calcium, and vitamin B12 after all procedures that bypass the lower stomach and proximal small intestine. Even with supplementation, iron, vitamin B12, folate, and calcium deficiencies may occur. Given the known poor compliance among adolescents,11 certain factors such as vitamin Bl, folate, and calcium warrant special consideration.

CHAPTER 80

A

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B

C

D

7 cm.

3 cm.

E

F

FIGURE 80-1 Roux-en-Y gastric bypass surgery. A, Sites for various laparoscopic ports. B, Preparation of the Roux limb. C, Mobilization of stomach. D, Preparing bypass pouch. E, Pouch is 3 cm wide and 7 cm long. F, Gastrojejunal anastomosis.

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Folate is specifically necessary for the synthesis of DNA and RNA and amino acid interconversion, particularly methylation reactions in the methionine-homocysteine cycle. It is essential for growth, cell differentiation, gene regulation, repair, and host defense.139,140,145 Folate deficiency is more prevalent in the general population than previously suggested. Adequate maternal periconceptional folic acid consumption during critical periods of organ formation may reduce the likelihood of neural tube defects, conotruncal structural heart defects, obstructive urinary tract abnormalities, limb defects, facial clefts, and congenital hypertrophic pyloric stenosis. Closure of the neural tube occurs between 26 and 28 days after conception (e.g., 1 to 2 weeks after the first missed menstrual period, before pregnancy is recognized). Folic acid supplementation started after this critical period is therefore unlikely to prevent a neural tube defect. Maternal folic acid deficiency is also associated with perinatal complications such as low birth weight, prematurity, placental abruption, infarction, and the development of neuroectodermal tumors in children. Folic acid deficiency, suggested by elevated plasma homocysteine, is also associated with cardiovascular diseases, increased risk of dysplasias, and the subsequent development of cancer. Given the protean manifestations of folic acid deficiency, the general recommendation is that all women of childbearing age take folic acid supplementation. In the adolescent who undergoes bariatric surgery, folic acid supplemented food items (such as cereals) may be inadequate. Additional supplementation contained in multivitamins is thus critical; measurement of serum folate and homocysteine concentrations may be useful.142,146–148 Adolescence is a period of enormous skeletal growth. This period of peak skeletal mineral accretion is a window of opportunity to influence lifelong bone health, both positively and negatively. Variations in calcium nutrition in adolescence may account for as much as 50% of the difference in hip fracture rates in postmenopausal years.149,150 Though it is generally assumed that the obese adolescent has greater than normal bone mass151 and is not operating at a disadvantage as it pertains to calcium absorption and risk for fracture or later osteoporosis, some experts disagree.152 It is not clear whether the decrease in bone density that occurs after surgical weight loss, combined with potential poor compliance with vitamin D and calcium intake, will put the adolescent bariatric patient at greater risk for fractures later in life. Thus we consider it essential to closely monitor bone mineral density of adolescents undergoing bariatric surgery, particularly gastric bypass and biliopancreatic diversion.

Guidelines for Performing Bariatric Surgery in Adolescence ------------------------------------------------------------------------------------------------------------------------------------------------

Severely obese adolescents who have failed nonsurgical attempts at weight loss and have serious comorbidities should be considered candidates for bariatric surgery. Current recommendations for patient selection can be found in Table 80-4. There are others with such extreme obesity that activities of daily living may be severely impaired and in whom the development of health consequences of obesity is inevitable. For adolescents who have failed 6 months of attempts at professionally supervised weight loss, bariatric surgery is a

TABLE 80-4 Recommendations for Patient Selection 1. Psychological maturity Demonstrates understanding of surgery and is compliant with preoperative therapy 2. BMI  35 with major comorbidities Type 2 diabetes mellitus Moderate to severe sleep apnea (AHI>15) Pseudotumor cerebri Severe NASH 3. BMI  40 with other comorbidities Hypertension Insulin resistance Glucose intolerance Impaired quality of life or activities of daily living Dyslipidemia Sleep apnea (AHI >5) 4. Individuals with mental retardation, syndromic obesity, and psychological disorders should be evaluated on a case by case basis From Pratt JS, Lenders CM, Dionne EA, et al.: Best practice updates for pediatric/adolescent weight loss surgery. Obesity (Silver Spring) 2009;17:901-910.

reasonable weight loss option. See Table 80-5. Increasing preoperative weight and male gender are risk factors for procedure-related complications and mortality.122,153 Given current referral patterns, the mean baseline BMI at our institution is 60.2 kg/m2.20 It is important for the surgeon to consider the impact of patient size on the potential for increased risks of the procedure. Some authors have suggested that surgeons who are early in the learning curve should avoid these high-risk patients to reduce complications.153 Adolescent bariatric surgery should be performed in centers having a multidisciplinary team capable of providing long-term follow-up and managing the unique behavioral challenges posed by the adolescent age group. Consistent with the guidelines established by the American Bariatric Surgical Association and the American College of Surgeons, these teams should include specialists with expertise in adolescent obesity evaluation and management, psychology, nutrition, physical activity instruction, and bariatric surgery. Depending on individual needs, additional expertise in adolescent medicine, endocrinology, pulmonology, gastroenterology, cardiology, orthopedics, TABLE 80-5 Attributes of Adolescent Bariatric Candidate • • • • • • • • • • • •

Patient is motivated and has good insight Patient has realistic expectations Family support and commitment are present Patient is compliant with health care commitments Family and patient understand that long-term lifestyle changes are necessary Agrees to long-term follow-up Decisional capacity is present Well-documented weight loss attempts No major psychiatric disorders that may complicate postoperative regimen adherence No major conduct/behavioral problems No substance abuse in preceding year No plans for pregnancy in upcoming 2 years

CHAPTER 80

and ethics should be readily available. The team approach should include a review process similar to that used in multidisciplinary pediatric oncology and transplant programs. This review should result in culturally sensitive treatment recommendations tailored for the patient and family. The optimal timing for weight loss surgery for overweight adolescents is unknown and largely influenced by the pressing health needs of the patient. There are growth and maturation factors that need to be considered. Physiologic maturation is generally complete by sexual maturation (Tanner) stage 3 or 4. Skeletal maturation (adult stature) is normally attained by the age of 13 to 14 in girls and 15 to 16 in boys. Overweight children generally experience accelerated onset of puberty. As a result, they are likely to be taller and have advanced bone age compared with age-matched, nonoverweight children. If there is uncertainty about whether adult stature has been attained, skeletal maturation (bone age) can be objectively assessed with a radiograph of the hand and wrist. If an individual has attained greater than 95% of adult stature, it is unlikely that a bariatric procedure would significantly impair completion of linear growth. In determining patient suitability, all candidates should undergo a comprehensive psychologic evaluation. Goals of this evaluation are (1) to identify psychologic stressors or conflict within the family; (2) to identify past/present psychiatric, emotional, behavioral, or eating disorders; (3) to define potential supports and barriers to patient adherence, as well as family readiness for surgery and the required lifestyle changes (particularly if one or both parents are obese); (4) to assess whether there are reasonable outcome expectations; and most importantly, (5) to determine the level of cognitive and psychosocial development of the adolescent. With the alterations in eating patterns that are required after bariatric surgery, repetitive reinforcement is necessary to facilitate the formation of lifelong health-promoting habits. Bariatric surgical programs for this age group should be based on the premise that sustained weight control for the adolescent requires intensive and regular postoperative psychologic support. The role of the behavioral therapist depends on the level of intellectual function of the adolescent and includes behavioral rehearsal of regimen components before surgery, the use of behavioral contracts to outline regimen requirements and document the patient’s agreement to adhere, a plan for patient and parental monitoring of adherence, and contingency reinforcement for adherence. The therapist plays a central role in developing parent-adolescent communication and conflict resolution skills and empirically based behavioral and family interventions, which facilitate the family’s management of the patient’s new lifestyle. A stable family environment, with full, unconditional support of all family members, is a desirable prerequisite for bariatric surgery in adolescents.

Clinical Pathway for the Management of the Adolescent Undergoing Bariatric Surgery ------------------------------------------------------------------------------------------------------------------------------------------------

The long-term consequences of bariatric surgery performed on adolescents have not been prospectively evaluated. The goals of adolescent bariatric surgery centers and programs

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should be to not only achieve dramatic and sustained weight loss but also contribute to the understanding of the most effective operations, risk factors for recidivism, and long-term outcome of adolescents undergoing bariatric surgery. Centers performing adolescent bariatric surgery should pay particular attention to bone mineral density and the ramifications of lifelong decreased vitamin and nutrient absorption on the adolescent and, particularly relevant to reproductive females, their offspring. Progress in this regard will require the implementation of broad-based clinical and basic research programs at these centers. The potential benefits of regionalizing selected, complex surgical procedures such as adolescent bariatric surgery have been well documented.154–159 To this end, adolescent bariatric surgery should be concentrated in centers willing and able to provide comprehensive and extended preoperative and postoperative investigations including laboratory and diagnostic evaluations. Therefore the clinical pathway developed by the Comprehensive Weight Management Center at Cincinnati Children’s Hospital Medical Center is designed to better characterize the prevalence and resolution of obesity-related complications among adolescents who undergo bariatric surgery, as well as provide surveillance for the known and potential consequences of the more popular bariatric surgical procedures performed at a comparatively young age. Our preoperative panel includes a complete chemistry profile, liver function tests, uric acid, transferrin, iron, folate, lipid profile, urinalysis, electrocardiogram, cell blood count, hemoglobin A1C, fasting blood glucose and fasting insulin levels, thyroid stimulating hormone, and a pregnancy test for females. Nondiabetics receive a 2-hour glucose tolerance test. With the exception of the glucose tolerance test, the aforementioned laboratory and diagnostic panels are repeated at 3, 6, 9, and 12 months postoperatively, then yearly. Body composition is assessed with either bioelectrical impedance, for patients weighing in excess of 300 lb, or dual energy x-ray absorptiometry analysis (DEXA), for patients weighing less than 300 lb preoperatively and annually postoperatively. DEXA not only allows for the measurement of rate and relative amounts of fat and lean body mass loss but also provides a quantitative assessment of changes in bone mineral density. This body composition analysis is used to modify dietary plans intended to preserve lean body mass during the period of dramatic weight loss. Evidence suggesting that even as little as a two-standard-deviation change in bone mineral content of the adolescent can significantly increase the risk of osteoporosis and bone fractures in later life underscores the importance of meticulous and extended monitoring of nutrient, vitamin, and mineral absorption.160 Because of the increased prevalence of abnormal heart geometry161–163 and sleep disorders80 among obese adolescents compared with nonobese adolescents, candidates for bariatric surgery undergo echocardiography and pediatric specific polysomnography. Adolescent obesity may represent a disease that is more serious2 and more difficult to manage11,13 compared with this disease in adults. We currently lack an understanding of the long-term outcomes (both positive and negative) of bariatric procedures in this population. Thus centers offering bariatric care to these patients are obligated to critically evaluate outcomes, both positive and potentially negative, by ensuring that a mechanism is in place to carefully collect detailed data regarding comorbidity change and adverse events on all

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adolescents who undergo surgery. This will help us to better define the role of bariatric procedures in the management of these patients. Ongoing longitudinal studies such as TeenLABS (http://www.teen-labs.org) will provide long-term data to allow us to better understand the impact of bariatric surgery on the adolescent.

Conclusion ------------------------------------------------------------------------------------------------------------------------------------------------

The obesity epidemic in this country has generated a population of adolescents with the premature onset of adult disease. Clinical and epidemiologic studies have elucidated some of the life course risk factors for the development of childhood and adolescent obesity. Currently, bariatric surgery is the most effective treatment that achieves sustained weight loss and resolves or ameliorates the majority of the associated comorbidities. Success in adolescent bariatric surgery should be defined not only in terms of weight loss and morbidity resolution but also in terms of normal progression through adolescence and adulthood. Toward this goal adolescent bariatric surgery programs should have expertise that increases the likelihood of lifelong compliance with complex nutritional and lifestyle regimens (i.e., expertise that enables them to assess and meet the

unique medical, cognitive, physiologic, and psychosocial needs of the adolescent). The guidelines for bariatric surgery should be conservative, be sensitive to the potential impact on the growth potential of the adolescent, and offer surgery during the time course of the disease that minimizes the risk of procedure-related complications and ensures the greatest likelihood of treating the comorbidities associated with obesity. Adolescent compliance with the strict nutritional and lifestyle regimens required after bariatric surgery may be best managed with a family-centered team that incorporates behavioral strategies to maximize compliance with postoperative dietary and physical activity instructions. Bariatric surgery is an exceedingly complex and technically difficult operation. The relative effects of hospital volume and surgeon volume in terms of procedure-related mortality and outcomes have direct implications for volume-based referral. Given the existent uncertainty about long-term outcomes of bariatric surgery in adolescents, regionalization of care and a national patient database are essential to achieve outcomes commensurate with the best adult series and to accelerate our understanding of the short- and long-term consequences of bariatric surgery among adolescents. The complete reference list is available online at www. expertconsult.com.