Learning Objectives: After reading this article, the physician should be better able to:
1. Relate a basic understanding of the anatomic and physiologic features of various bariatric surgical procedures.
2. Classify common surgical complications of bariatric surgery to determine which therapy to institute.
3. Categorize common metabolic complications of bariatric surgery.
Article from the 2010 LLSA Reading List
Presentation and Management of Common Post-Weight Loss Surgery Problems in the Emergency Department
Edwards ED, et al
Ann Emerg Med
This article summarizes four different approaches to surgical weight loss, reviews common side effects and complications associated with each, and offers some practical advice for evaluating bariatric surgery patients in the emergency department. Obesity in the United States is epidemic, and weight-loss surgery is rapidly gaining popularity. If you haven't already come across a patient in your ED with a bariatric surgery-related complication, you're likely to see one soon. This article will help you understand the anatomical features and physiologic principles of various bariatric procedures, critical steps in determining what complication your ED patient has, how to initiate management, and ultimately how to make your patient better.
Bariatric surgical procedures achieve their goal via two basic principles: restricting caloric intake and reducing absorption. Restrictive procedures are designed to limit the amount of food intake (and subsequent caloric intake) by physically decreasing the size of the functional stomach pouch. The patient experiences early satiety, and theoretically, caloric intake is reduced. Procedures that include malabsorptive properties limit transit through functioning intestine, and result in even more rapid and sustained weight loss, but they are associated with specific nutritional complications.
Vertical banded gastroplasty (VBG), an exclusively restrictive procedure, involves making the available pouch much smaller along the lesser curvature of the stomach by stapling its walls together vertically. A nonadjustable band is then added to limit outflow from the newly created pouch. Early postoperative complications are similar to other laparoscopic abdominal surgeries, including infection and bowel obstruction. Long-term side effects include reflux and vomiting. Although most of these patients initially lose at least 50 percent of their excess weight, long-term follow-up in one study showed that only 20 percent of these patients maintained their weight loss after 10 years. Seventeen percent of these patients required another bariatric surgery due to either inadequate weight loss or long-term side effects. (J Gastrointest Surg 2000;4:598.)
Laparoscopic adjustable gastric banding (LAGB) has largely replaced VBG as the laparoscopic bariatric procedure of choice. With LAGB, an adjustable, inflatable band is positioned proximally around the stomach extending from the smaller curvature to the larger curvature. An access port, used to infuse or remove normal saline, is placed subcutaneously to adjust band tightness over time depending on symptoms or weight loss. Because the band may cause postoperative stomach edema and subsequent vomiting or even obstruction, the band is not inflated in the immediate postoperative period. Although seemingly less invasive than VBG, LAGB has unique complications to consider, including those related to the access port (infection, leakage, skin ulceration, failure) and those related to the band (proximal slippage, distal migration, gastric erosion, gastric necrosis, and frank perforation).
Two specific long-term complications of LAGB, which the authors mention in detail, are gastric obstruction and gastric erosion. Distal migration of the band even years after the procedure can lead to stomach dilation and subsequent vomiting or obstruction. According to the article, if gastric obstruction from the band is suspected, the physician should consider deflating the band by removing saline from the access port as soon as possible to prevent gastric perforation. The band can also erode chronically through the entire stomach wall, causing intra-abdominal abscess, sepsis, or perforation.
According to the article, Roux-en-Y gastric bypass is the most commonly performed bariatric surgery. In this procedure, the stomach is completely bisected, and two limbs of the digestive tract are created. The Roux limb, which still communicates with the esophagus, contains a newly created small stomach pouch (about 30 cc), and is connected to the remainder of the GI tract via a gastrojejunostomy. The other limb (biliopancreatic) is one-sided, and formed from the remainder of the transected stomach, pylorus, and duodenum, and communicates with the rest of the GI tract via a jejunojejunostomy. With both restrictive and malabsorptive features, the Roux-en-Y procedure has been shown to result in maintenance of 80 percent of excess body weight loss at five years. (Obes Surg 2000;10:233.)
Standard perioperative complications exist (anesthesia, bleeding, venous thrombosis, infection) in addition to those more specific for intra-abdominal surgery (anastomosis leak). Later complications include small bowel obstruction from adhesions, anastomotic stricture, and external or internal hernias. Because the biliopancreatic channel does not communicate with the esophagus, complications in this limb can be very challenging to recognize. In the immediate postoperative period, bleeding from the blind stomach limb cannot be visualized endoscopically, and obstruction of the biliopancreatic limb may not present with vomiting or show air fluid levels on plain films or even CT.
Malabsorptive weight loss surgery such as the Roux-en-Y gastric bypass also can result in nutritional deficiencies (iron, thiamine, vitamin B12, vitamin D, calcium) and their associated disease manifestations (anemia, neuropathy, secondary hyperparathyroidism, osteomalacia) so lifelong nutritional supplements and monitoring are required.
Biliopancreatic diversion with duodenal switch is the final bariatric surgery discussed in the article. Of all the procedures, it is the most invasive and results in the most malabsorption, potentially achieving the most weight loss. For restrictive effects, a banana-shaped stomach sleeve is formed by transecting the stomach in a longitudinal arc following the greater curvature. The pylorus and first part of the duodenum are left attached to the stomach. To achieve malabsorption, the biliary-pancreatic system and most of the small bowel are bypassed by completely transecting the duodenum proximal to the ampulla of Vater. This proximal segment of duodenum is then reattached to the ileum (duodenal switch), reforming a continuous alimentary canal. The distal segment of transected duodenum is closed to form a blind pouch, and becomes part of the biliopancreatic limb, which includes the biliopancreatic system and the majority of bypassed small bowel. Distally, this limb is attached to the ileum, forming a common channel.
Purported advantages of biliopancreatic diversion with duodenal switch include less restrictions on caloric intake because a larger stomach pouch (about 200 cc) is left behind, less likelihood of the dumping syndrome because pylorus function is left intact, and more excessive weight loss due to the extreme malabsorptive nature of the procedure. Potential disadvantages include higher short-term surgical risks, higher long-term risk of severe metabolic derangements, and a high incidence of malabsorptive diarrhea. Hepatic dysfunction and even frank liver failure have been associated with biliopancreatic diversion.
Comment: The National Center for Health Statistics report on U.S. health in 2009 offers a startling look at the rate of obesity in this country. In 1960, only 13 percent of adult Americans were obese. (National Health Examination Survey, Cycle I. 1962; www.cdc.gov/nchs/products/elec_prods/subject/nhes1.htm). Today, according to data from the most recent National Health and Nutrition Examination Survey (NHANES) in 2007 and 2008, more than one-third of adult Americans (34%) now meet criteria for obesity (BMI>30), and more than two thirds (68%) are considered overweight (BMI>25). (JAMA 2010;303:235.)
With the number of obese Americans at epidemic proportions, the demand for surgical weight loss solutions has also increased. In Southern California, it's difficult to drive more than just a few miles before either hearing a radio advertisement or seeing a roadside billboard offering the latest innovations in bariatric surgery. Of course, each alternative has affordable payment plans in case you don't have insurance or the procedure is not covered. I found nine specialists who offer the same procedure within a 10-mile radius of where I live. Deal hunters can consider traveling to various tropical destinations where board certified foreign physicians will do your procedure at bargain prices, and even offer to cover your airfare and hotel accommodations.
With so many options available and a growing number of centers, it is more likely every day that you'll come across one of these patients postoperatively in the ED. As the authors in this article point out, these patients are often difficult to evaluate. Soon after bariatric surgery, many patients are still morbidly obese, making the abdomen extremely difficult to examine. These patients also have multiple comorbidities, including diabetes and low cardiopulmonary reserve, meaning they can potentially deteriorate rapidly when they are ill. Altered anatomy postoperatively also can alter symptom presentation (blind-loop hernia or obstruction) and make imaging much more difficult to interpret. Making matters worse, our trusted fallback test for abdominal symptoms, the abdominal CT, which we increasingly depend on as our collective clinical skills deteriorate, often becomes unavailable to patients beyond a certain weight. Threshold for surgical consultation in these patients should be low. Quoting the authors directly: “Any [postoperative bariatric surgery] patient with unexplained abdominal pain, regardless of laboratory or radiologic findings, should be considered for surgical exploration.”
Bariatric surgery also offers many potential health benefits. According to the Swedish Obese Subjects Study, a large nonrandomized trial of bariatric surgery vs. conventional weight loss therapy found a significantly reduced incidence of diabetes and hypertriglyceridemia at both two years and 10-year follow-up in bariatric surgery patients. (N Engl J Med 2005;352:1495.) More recently, a very small randomized controlled trial (n=60) comparing LAGB with an intensive conventional therapy program for weight loss, showed surgical patients were more likely to achieve remission of Type II diabetes after two years. Ultimately, however, the study concluded that larger trials with longer follow-up were necessary.
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