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Bariatric surgery is the current standard treatment for severe obesity. A variety of procedures are currently performed, which provide durable and rapid weight loss through malabsorption, restriction, or a combination of the two. The significant amelioration of obesity-associated comorbidities has been demonstrated. Laparoscopic techniques in bariatric surgery provide patients with decreased morbidity and faster recovery, with an equivalent amount of weight loss. Weight loss is dramatic and progressive until a plateau is reached. Patients often seek the services of a plastic surgeon to remove the excess lax skin and improve the ptosis associated with such massive weight loss.
Obesity has reached epidemic proportions in the United States and is increasing worldwide. Of all available methods, bariatric surgery has proved to be the most effective long-term treatment for obesity by its ability to provide sustained weight loss as well as amelioration of obesity-related comorbidities. Laparoscopic bariatric surgery, in particular, allows faster recovery and improvement in quality of life while avoiding the wound and abdominal wall complications associated with open procedures. Once the rate of weight loss has reached a plateau at about 12 to 18 months postoperatively, many of these patients become candidates for body contouring surgery and other aesthetic operations. This overview on bariatric surgery focuses on selection of patients, operative techniques, postoperative management, and complications. Nutritional guidelines and the characteristics of weight loss are discussed, as well as the long-term health benefits. Finally, the role of plastic surgery is briefly discussed. The increasing prevalence of obesity has resulted in increased interest and success with surgical treatments. As a result of this success, patients who undergo dramatic weight loss also have large amounts of excess skin. This has resulted in an increased need for body contouring operations.
Nearly two thirds of adults in the United States are overweight, and almost one third are obese. The most common measure of obesity is the body mass index, or BMI, which is calculated by dividing a patient's weight in kilograms by the square of the height in meters (kg/m2). A patient is considered overweight with a BMI ranging from 25.0 to 29.9 kg/m2, and a BMI above 30 kg/m2 is considered obese. In addition, waist circumference has been used as an estimate of abdominal fat, and its increase represents an elevated health risk independent of the BMI. Specifically, a circumference of 35 inches or greater in women and 40 inches or greater in men has been shown to be associated with an increased risk of diabetes, hypertension, and dyslipidemia.1 Nonsurgical methods of weight loss result in only modest success and results are usually temporary. Surgical weight loss has been proved an effective and durable solution for patients with morbid obesity.2 Surgical treatment for obesity is indicated for patients who are 100 pounds overweight or who have a BMI of 40 kg/m2 or greater. Individuals with a BMI of 35 kg/m2 or greater who have comorbid conditions such as diabetes mellitus, hypertension, hyperlipidemia, or sleep apnea are also candidates for surgical treatment. The most common comorbid condition is hypertension, followed by gastroesophageal reflux disease, osteoarthritis, sleep apnea, and diabetes.3
Preoperative evaluation is extensive. Interested patients complete a thorough questionnaire that includes demographics, comorbidities, medications, and past medical and surgical history. Patients then attend a group information session and undergo a history and physical examination. The history focuses on prior attempts at weight loss (including diet plans and behavioral or medical therapies), exercise habits and daily levels of activity, effects of obesity on the patient's health, and expectations of both the surgery and the resulting lifestyle changes. In addition to standard preoperative laboratory tests, the blood work includes albumin, hemoglobin A1c, a lipid panel with cholesterol, and thyroid function tests. A chest radiograph and electrocardiogram are obtained, and the patient should preferably have medical clearance from his or her primary care physician. Cardiac workup is required for patients with any evidence of cardiovascular disease on screening or those with risk factors, such as diabetes or hypertension. Patients with complaints of loud snoring or excessive daytime drowsiness are worked up for sleep apnea by polysomnography. Upper endoscopy is performed to rule out esophagitis, Barrett's esophagus, and peptic ulcer disease. Consultations with a dietitian and a psychiatrist are mandatory. Contraindications to surgery include a history of unresolved alcohol or substance abuse, unstable psychiatric illness, an inability or unwillingness to cooperate in postoperative requirements and follow-up, and a lack of understanding or unrealistic expectations surrounding the operation.
Laparoscopy for bariatric surgery has proved to be a safe and cost-effective alternative to open procedures. Ventral hernias and wound infections have been reported to occur in up to 16% to 20% of patients after the open gastric bypass, whereas laparoscopy has greatly reduced the incidence and severity of these complications.4,5 Patients have a shorter hospital stay and faster recovery, with decreased pain and a reduction in pulmonary dysfunction.4,6 Patients report a more rapid improvement in quality of life, manifested by an earlier return to activities of daily living and return to work, more interest and participation in physical and social activities, and a greater initial weight loss at 3 and 6 months.4,5 Laparoscopic bariatric surgery is the standard at our institution, and the following discussion refers to the laparoscopic approach.
The surgical procedures available for treatment of obesity involve either purely restrictive or combined restrictive and malabsorptive procedures. Purely restrictive procedures function by reducing the functional capacity of the stomach and include the vertical banded gastroplasty and the adjustable gastric band.
In the vertical banded gastroplasty (VBG), a vertical pouch is created using a surgical stapler along the lesser curvature. A prosthetic band is used to maintain the outlet of the pouch. The advantages of the VBG are that there is no anastomosis, and thus reduced risk of leakage, and malabsorption is avoided. Unfortunately, the VBG has not proved to be successful at durable postoperative weight loss.7 A significant number of patients require revision for complications, including inability to maintain weight loss, staple line breakdown, severe gastroesophageal reflux, and stomal stenosis.7,8
The laparoscopic adjustable gastric band (LAGB) has been used extensively outside the United States and is the most common laparoscopic bariatric procedure worldwide because of its popularity in Europe and Australia. In the United States, Food and Drug Administration approval was obtained in June 2001, and so the experience is still somewhat limited. The band consists of silicone and is placed around the superior portion of the stomach, just distal to the gastroesophageal junction (Fig. 1). There is an inflatable reservoir that can be adjusted postoperatively by a subcutaneous port. Percutaneous injection or withdrawal of saline allows adjustment of the diameter of the pouch lumen, as measured by barium studies, and can be regulated based on the patient's hunger, rate of weight loss, and volume of food he or she is able to eat.9 It is also reversible, unlike the other available procedures. Although operative and early complications have been reported, including bleeding and esophageal or gastric perforation, the procedure is relatively safe. Late complications, which may require reoperation, include food intolerance, band slippage, pouch dilatation, and band erosion. In the United States, weight loss results have been less dramatic than with restrictive and malabsorptive operations, and amelioration of obesity-related comorbidities has not been demonstrated consistently, particularly when compared with gastric bypass.10,11,12 Studies from other countries, however, have reported superior results, and large, long-term studies from the United States may follow.
One type of primarily malabsorptive procedure is the biliopancreatic diversion (BPD) performed with or without duodenal switch (DS). The operation involves a lateral gastrectomy involving the greater curvature, leaving a larger pouch based on the lesser curvature, and the pylorus remains intact (Fig. 2). The first portion of the duodenum is divided and anastomosed to the distal small bowel, creating a 150-cm alimentary limb through which food passes from the stomach. The biliopancreatic limb, which carries the bile and pancreatic secretions, is anastomosed 100 cm from the ileocecal valve, creating the 100-cm common channel.13,14 This is a technically more complex operation, especially because of the presence of a duodenal resection, and it carries slightly higher morbidity and mortality. Food tolerance is increased, due to the greater size of the gastric pouch as compared with the gastric bypass, and there is also a decrease in the incidence of certain gastrointestinal side effects such as dumping syndrome and regurgitation.14,15 The BPD-DS creates significant fat and protein malabsorption. Patients require supplementation of the fat-soluble vitamins A, D, E, and K. Occasionally, malabsorption becomes severe enough to require hospitalization with parenteral nutrition. A large number of patients also complain of significant foul-smelling loose stools and flatus.14 There is some controversy regarding whether weight loss is superior to that seen with the gastric bypass, particularly in patients with a BMI greater than 60 kg/m2, however, there have been no randomized controlled trials comparing the procedures, and thus far the results may be comparable in terms of weight loss. 16,17,18
The most common and successful procedure for obesity is the laparoscopic Roux-en-Y gastric bypass (LRYGB), considered by many to be the “gold standard.” This procedure has undergone multiple revisions, but currently, at the University of Pittsburgh, it consists of a 15-mL gastric pouch, a two-layer gastrojejunal anastomosis (sutured outer layer with stapled inner layer), an antecolic, antegastric Roux limb, and a stapled jejunojejunostomy.19 Six laparoscopic ports are used, four 5-mm trocars, and two 12-mm trocars (Figs. 3 and and4),4), and the operation usually takes from 1 to 2.5 hours to complete. The alimentary limb is typically 75 cm and is often elongated to 150 cm in the “long-limb” gastric bypass performed for patients considered superobese, typically with a BMI greater than 50 kg/m2, or those with diabetes. The gastric pouch anastomosis is tested with air insufflation by intraoperative endoscopy. Patients receive antibiotic prophylaxis prior to the procedure as well as deep venous thrombosis (DVT) prophylaxis in the form of subcutaneous heparin and sequential compression devices.
Postoperatively, the patients are admitted to a specially equipped surgical unit with continuous pulse-oximetry monitoring. Patients receive additional anticoagulation and continue to wear sequential compression devices while in bed. Patient-controlled analgesia (PCA) is used for analgesia for the first 24 hours, and an antiemetic is also prescribed on a regular basis. The patients ambulate beginning the night of surgery. On the first postoperative day, the patients undergo an upper gastrointestinal series with diatrizoate meglumine (Gastrografin) and barium to evaluate for leaks and obstruction. If this is normal, the patients are started on a diet of clear liquids (30 mL every 30 minutes). In addition, the urinary catheter is removed and oral pain medications replace the PCA. On the second postoperative day, the patients are advanced to a diet of 60 mL of clear liquids every 30 minutes. If they are able to tolerate the diet and remain stable, the patients are discharged that day.
Complications can be divided into early and late. Excluding pulmonary embolism, an anastomotic leak is the leading cause of death in the immediate postoperative period and has an incidence of about 1% to 4%.5,20,21 Although it is routine for some surgeons to obtain a contrast study on the first postoperative day, anastomotic leaks are unfortunately not always detected with this modality. The most common presenting symptoms are subtle and include tachycardia, fever, left shoulder pain, and leukocytosis; however, clinical presentation in this population of patients may be nonspecific. Leaks may occasionally be managed conservatively, with drainage and total parenteral nutrition (TPN), or may require reoperation with drainage and placement of a gastrostomy tube.
Prophylaxis against lower extremity deep venous thrombosis and pulmonary embolism is both mechanical and pharmacologic in nature. Sequential compressive devices are placed and activated prior to induction of anesthesia, and all patients receive fractionated heparin. Patients are encouraged to ambulate as early as possible and are continued on the sequential compressive devices as well as the low-molecular-weight heparin until discharge. Extended home anticoagulation is prescribed for patients with increased risk for deep venous thrombosis, such as those whose BMI is greater than 60 kg/m2 or who have a prior history of venous thrombosis or pulmonary embolism.
Two common late complications after gastric bypass are stenosis of the gastrojejunal anastomosis and small bowel obstruction. Anastomotic stenosis may arise with dysphagia, nausea, or regurgitation. The patients often complain of symptoms immediately after eating. The stenosis is commonly treated with endoscopic balloon dilatation, which may require repeated application.5,21,22,23 In laparoscopically treated patients, postoperative bowel obstructions are usually due to an internal hernia, rather than adhesions, and most commonly result from mesenteric defects related to the Roux limb.24 Operative repair is required, but the incidence has decreased with awareness and some modifications in technique, such as placing the Roux limb in an antecolic, antegastric position. Other complications include marginal ulcers, cholelithiasis, and dumping syndrome. The dumping syndrome is one of the most common complications of gastric bypass surgery and is caused by rapid gastric emptying of a hyperosmolar load into the small intestine. The syndrome usually consists of both gastrointestinal and vasomotor symptoms occurring within 30 minutes after a meal. The gastrointestinal symptoms include nausea, vomiting, epigastric fullness, and crampy abdominal pain; cardiovascular symptoms include palpitations, diaphoresis, dizziness, and flushing.25 The mainstay of therapy is diet modification, including the use of small, frequent meals, intake of liquids 30 minutes after the meal, and avoidance of sweets. The small percentage of patients not responding to these measures may be helped by the use of octreotide (a somatostatin analog) given prior to the meal.25 Although viewed by some as a complication, dumping is considered a beneficial side effect because of its powerful ability to modify feeding behavior.
Cholelithiasis is a known risk of both obesity and rapid weight loss because of the decreased solubility of bile salts, leading to sludge and possible stone formation. The gallbladder is not routinely removed at the time of surgery if the patient is free of stones and asymptomatic; however, the risk of cholelithiasis with postoperative weight loss is 30%. Ursodiol has been proved to increase the solubility of bile salts and can decrease the risk of gallstone development to 1% to 2%.26 The ursodiol is taken throughout the duration of the patients' significant weight loss, that is, a loss of greater than 3% of body weight per month, which usually corresponds to the first 6 postoperative months.
The initial postoperative diet (phase I) is clear liquids for the first week. Patients are encouraged to increase liquid intake to about 64 ounces per day. Patients are seen in the clinic after 7 days and are advanced to a phase II diet. This is a pureed diet, consisting of three meals a day, and initially consists of only one to two tablespoons. The patients still need to consume the 64 ounces of fluid per day to avoid dehydration. All patients are required to take supplemental vitamins (including B12), iron, and calcium. After approximately 1 month, patients are seen again in the clinic and begin a soft diet high in protein. They are also encouraged to begin an exercise program. Follow-up intervals in the first year are at 3, 6, 9, and 12 months; thereafter, they are seen every year for life. Laboratory tests for nutritional parameters are obtained every 12 months.
Weight loss is typically described as a percentage of either excess body weight (EBW) or initial body weight lost (IBWL). Average weight loss typically exceeds 60% EBW within 6 months of surgery and rises to a mean of close to 80% at 1 year. One large study demonstrated EBW loss of 83% at 24 months and 77% at 30 months.5 This weight loss is well maintained, as demonstrated by one study observing patients for up to 60 months postoperatively.27 The rate of weight loss obviously depends on several factors related to the patient's lifestyle and adherence to the dietary restrictions and also depends upon the preoperative BMI. Patients with a BMI greater than 55 kg/m2 typically lose about 11 to 14 kg (24 to 30 lb) in the first month and 9 kg (20 lb) per month for the next 3 months; for patients with a lower BMI, 35 to 40 kg/m2, weight loss is somewhat less. The use of a dietitian is extremely helpful to the patients during this immediate follow-up period.
Not only is quality of life often significantly improved after bariatric surgery but also the patients show clinical improvement or resolution of most obesity-related comorbidities. Patients with type 2 diabetes mellitus, while achieving a slightly lower mean total EWL at 60.1%, demonstrated clinical resolution of their disease, defined as cessation of diabetic medications, in about 80% to 98% after LRYGB and 96% to 100% after BPD.28,29 Most remaining patients are able to decrease their medication requirements postoperatively.28 Patients with impaired glucose tolerance had an even more impressive response to bariatric surgery, with an almost 99% rate of euglycemia postoperatively.30 In addition, bariatric surgery has been shown to reduce mortality from cardiovascular disease associated with diabetes.31 Other comorbidities that are ameliorated include gastroesophageal reflux disease, sleep apnea (both eliminated in 98% of patients), hypertension (eliminated in 92% with decreased medication requirements in most other patients), degenerative joint disease, dyslipidemia, and peripheral edema.5,32
Because of the rapid loss of 100 or more pounds, the decrease in subcutaneous tissue obviously results in skin laxity, producing skin that is usually overstretched and without potential for retraction. The redundant skin is most prevalent in the chest, abdomen, buttock, thighs, and upper arms. Timing of body contouring surgery should be determined by the stabilization of the patient's weight, which usually occurs within 12 to 18 months after a bariatric surgical procedure. A large and heavy hanging panniculus can interfere with exercise and even normal activities and can cause lower back pain. Rashes and skin irritation are common, particularly in warm weather. Less commonly, the ongoing irritation can lead to lymphedema, intertrigo, panniculitis, and chronic infections. Skin rashes and irritation can also occur in folds of skin under the breasts and on the thighs and back. In addition to the cosmetic concerns, excess skin on the upper arms may cause discomfort during physical activity.33,34,35
The most effective treatment for morbid obesity is weight loss surgery, which provides rapid and sustained weight loss and provides significant improvement or resolution of many obesity-associated comorbidities. All of the discussed laparoscopic bariatric procedures provide a rapid improvement in quality of life. A major contributor to the patients' increased comfort and self-confidence after massive weight loss is the subsequent body contouring operation to remove the resulting loose skin. As the epidemic of obesity increases, the number of patients undergoing bariatric surgical procedures will also continue to increase, and the demand for plastic surgery will continue to rise.