By: Camelia A. Davtyan, MD; David G. Davtyan, MD
Obesity is becoming a global health problem; with 8.2% of the world population classified as obese. The World Health Organization estimates that the number of obese adults increased by 50% to 300 million between 1985 and 2000. In 1999, 27% of US adults were obese (body mass index [BMI] greater than 30 kg/m2), and 61% were overweight (BMI greater than 25 kg/m2). This represents a major upsurge from only two decades ago, when the prevalence of obesity in the United States was 15% and 46% of adults were overweight. It is estimated that approximately 300,000 deaths per year are due to obesity, and because the prevalence of obesity is growing, mortality from the condition may soon exceed smoking-related mortality.
The average American gains about 20 lb between the age of 25 and 55 years, which can result from consuming as little as 6 kcal/d over the individual’s metabolic rate. There are more men than women with a BMI of 25 to 29.9, but women match or exceed men when it comes to BMI greater than 30. Black women have an incidence of obesity 80% higher than their male counterparts, and Mexican American women also have a higher incidence of obesity than Mexican American men. Most obese women gain their excess weight after puberty, often associated with pregnancy, hormonal contraceptives, and/or menopause.
There is a growing concern regarding comorbidities affecting more than 14 million obese Americans. Hypertension, type 2 diabetes, dyslipidemia, coronary artery disease, sleep apnea, asthma, gastroesophageal reflux, degenerative joint disease, parenchymal liver disease, gallbladder disease, certain malignancies (breast, colon, prostate, kidney, esophagus, endometrium), infertility, and premature death are all more common among the obese population. It was estimated in 1996 that the cost of obesity-related morbidity had mounted to 6.8% of the total US health care expenditure.
Most long-term studies of obesity treatment show a high prevalence of weight regain; indeed, more than 33% of patients who had lost weight, regained one third of it within 1 year and almost 100% of it within 5 years. In 2000, the National Institutes of Health (NIH) developed evidence-based guidelines for obesity treatment based on almost 400 randomized controlled trials of obesity therapy. These guidelines endorse diet, physical activity, and behavioral therapy for all patients with a BMI of 25 to 29.9 with comorbidities. If diet and exercise fail, the NIH also endorsed pharmacotherapy for people with a BMI exceeding 30 with out comorbidities. Surgery is recommended for patients with a BMI greater than 40 (or greater than 35 with comorbidities) when less invasive methods have failed and the patient is at risk for obesity-associated morbidities and mortality.
Life-style changes are the first line of therapy for over-weight and obese individuals. Low-calorie diets can reduce body weight by 8% over 6 months, and regular exercise (three to seven sessions of 30 to 60 minutes each per week) can produce weight loss of 2% to 3% independent of diet. Ongoing behavioral therapy can increase compliance with life-style changes, and can support weight reduction. A combined approach of low-calorie diet, regular exercise, and behavioral therapy is recommended by the NIH guidelines.
Pharmacotherapy is a second-line approach when life-style changes alone do not achieve weight loss. It can produce 6% to 10% weight loss at 1 year, with a significant risk of regain after the medication is stopped. It should not be initiated unless the patient has demonstrated significant life-style changes involving diet, exercise, and behavioral modification. The long-term risks and benefits of these medications are unknown. Historically, amphetamines, phenylpropanolamine, phentermine and fenfluramine, orlistat, and sibutramine have been used to promote weight-loss. Fenfluramine was withdrawn from the market following reports of adverse effects on the heart and pulmonary arteries.
Bariatric Surgery is a third-line resort when life-style changes and medications are not successful. Most surgeons and health plan adhere to the 1991 NIH Consensus guidelines, which endorse surgical treatment for patients with a BMI greater than 35 with comorbidity, or a BMI greater than 40 with or without comorbidity. The only procedures endorsed by the panel at that time were gastric bypass and vertical banded gastroplasty. Over the past decade, bariatric surgery has gained acceptance among patients and physicians, most due to the development of a laparoscopic approach.
There are three ways of achieving surgical weight loss: gastric restriction, intestinal malabsorption, or a combination of the two. Gastric restriction procedures create a small gastric pouch that reaches early satiety. This pouch also has a small outlet that prolongs satiety by retarding the expulsion of its contents. Vertical gastric banding and small-pouch gastric bypass were the only procedures in this category, until the advent of laparoscopic adjustable gastric banding, which introduced the concepts of adjustability and reversibility. Dietary compliance is key to the restrictive procedures, because consumption of high-calorie liquids or soft foods will result in failure to lose weight. The benefits of restrictive procedures include avoidance of vitamin and mineral deficiencies and of protein energy malabsorption, plus technical ease compared with malabsorptive procedure. The drawbacks of these procedures are that they yield less weight loss and more late failures due to pouch dilation and excessive narrowing of the outlet. The adjustable bands are not associated with these later effects.
Malabsorptive procedures include biliopancreatic diversion, with or without duodenal switch, and distal gastric bypass. These procedures rely on primarily on bypassing a part of the small intestine to cause malabsorption, as well as a small gastric volume reduction. Disadvantages include the risk of malnutrition and vitamin deficiency, as well as more surgical complications because the procedures are more technically difficult.
The small pouch gastric bypass with Roux-en-Y reconstruction combines both restriction and malabsorption. This procedure is inherently associated with the complications related to both gastric restriction and intestinal malabsorption.
Laparoscopic bariatric surgery has been evolving since the early 1990s, leading to less perioperative morbidity and shorter recovery. Currently, the Roux-en-Y gastric bypass is the preferred procedure in the United States, and adjustable gastric banding is the most popular weight loss surgery outside the United States.
LAPAROSCOPIC ADJUSTABLE GASTRIC BANDING
The US Food and Drug Administration approved the LAP-BAND Adjustable Gastric Banding System in June 2001 following a 3-year multicenter trial that enrolled 303 women and 52 men. The first laparoscopic adjustable gastric banding procedure was performed in 1993, and since then, more than 80,000 obese patients have been treated with this approach around the world.
This procedure involves laparoscopic placement of a silicone band around the upper stomach. The band is connected through a catheter to a subcutaneous reservoir where saline solution can be injected to adjust the diameter of the band. Banding leads to early satiety and slow emptying of the gastric pouch. The procedure offers the advantage of minimal hospital stay (overnight), reduce pain, early return to normal activity, and complete reversibility. The patient will require a liquid diet for the first 2 to 4 postoperative weeks, after which soft and ten solid foods are introduced. Food must be eaten slowly and chewed thoroughly. Liquids are consumed 10 minutes before or 90 minutes after the meal, and should have no calorie content. The patient must exercise regularly to prevent the loss of lean body mass.
The overall morbidity rate for bariatric procedures varies from 11.3% for adjustable gastric banding to 23.6% for vertical banded gastroplasty and 25.7% for the Roux-en-Y gastric bypass. Possible complications of adjustable gastric banding include gastric pouch dilatation, port-tube complications, band erosion, gastric prolapse and erosion was highest right after the development of the procedure, and then decreased with the advent of the new pars flaccida surgical approach.
Most studies of weight loss after laparoscopic adjustable gastric banding have shown an average of 40% to 50%loss of excess body weight, which is gentle and progressive during three years of follow-up, and is similar to the results of other restrictive procedures. By contrast, weight loss after Roux-en-Y gastric bypass is more rapid, reaches a plateau, and is often followed by some regain over time- for an overall median weight loss of 60%-70% of excess body weight at 3-5 years. The malabsorptive procedures are associated with a 75% to 80% loss of excess body weight at 3 -5 years.
The progressive weight loss pattern with laparoscopic adjustable gastric banding reflects the benefit of adjustability, permitting variable degrees of restriction at different times after the procedure. The initial adjustment isn’t performed until 5-7 weeks post-procedure. If the patient has a prolonged sensation of satiety and is losing weight at a rate of 0.r to 1 kg per week, no adjustment is necessary. The patient should not experience restrictive symptoms after adjustments (vomiting, heartburn, excessive difficulty eating a variety of foods). The patient typically undergoes three to six adjustments in 1 year. The adjustments can be performed by the surgeon in the office setting, using radiographic guidance as desired.
Follow-up is scheduled every 4-6 years during the first postoperative year and every 3-6 months for 2 additional years, after which annual visits are sufficient if the patient is stable. Communication between the patient and primary care physician is essential, given the expected improvement in the patient’s associated morbidity (e.g., hypertension, diabetes) that will require changes in medication dosages and close follow-up of these patients’s nutritional and metabolic status.
The health benefits of laparoscopic adjustable gastric banding are similar to other bariatric procedures. Postoperative weight loss will produce resolution or remission of diabetes in 66% of patients, and improved glucose control in the remainder. The weight loss also prevents the development of type 2 diabetes in patients who otherwise would have been at high risk. The dyslipidemia of obesity should improve significantly post-procedure. Hypertension resolves in many patients, as does obstructive sleep apnea. Obese asthmatics do very well after this procedure, with major improvement and even remission. Gastroesophageal reflux can be eliminated by a correctly placed and properly adjusted band. Many pre-menopausal women with fertility problems become ovulatory within the first postoperative year due to a reduction in the total testosterone level and an increase in sex-hormone binding globulin values. The band can be adjusted during pregnancy to manage gestational emesis and ensure adequate nutrition. There is also a significant overall improvement in postoperative quality of life, including the psychological aspects of successful weight loss.
Selecting suitable candidates for this procedure is the key to ensuring a successful weight loss and avoiding morbidity. Age is a significant factor; at this point, patients younger than 18 years or older than 65 years are not considered suitable candidates, although older patients could become eligible in the future. Candidates with a BMI of 35 and comorbidity or a BMI of more than 40 should have a history of many attempts at weight loss resulting in temporary reduction of at least 10 lb. Patients should understand their essential role in achieving a positive outcome, and should be committed to dietary compliance. Men and women have equally good results following this procedure. Some authors consider a persistent craving for sweets to be a contradiction for this procedure, while others do not. Patients should have realistic expectations regarding both the benefits and risks of this procedure, and should undergo preoperative medical, nutritional, and psychological evaluation. This operation should never be performed for cosmetic reasons.
Laparoscopic adjustable gastric banding is the least invasive bariatric procedure currently available. It is associated with a 40%-50% loss of excess body weight, and a significant reduction in comorbid conditions related to obesity. Although direct comparative trials are lacking, current data suggest that laparoscopic adjustable gastric banding ahs the lowest rate of complications compared with all other types of bariatric surgery, and offers the best postoperative quality of life. The loss of excess body weight associated with the Roux-en-Y gastric bypass and malabsorptive procedures comes with a higher risk of morbidity.
Laparoscopic adjustable gastric banding has a significant potential to contribute to current efforts to control the national obesity epidemic in appropriately selected patients. Partnership among the patient, surgeon, and primary care physician is of utmost importance in ensuring long-term weight control in these patients.
The authors acknowledge Carolyn Crandall, MD, and Mina Ma, MD, for their thorough review of the script and valuable suggestions.
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