Types of Bariatric Surgery to Reduce Obesity Health Risks

by DocJohn
(California)

Surgical Options

Surgeons currently perform three types of weight loss surgery procedures — restrictive, malabsorptive, or a combination of both. Restrictive procedures involve the stomach only, reducing its volume with adjustable gastric banding or vertical-banded gastroplasty, so-called “stomach stapling.” The procedure helps patients lose weight by reducing their food intake. On the other hand, malabsorptive procedures facilitate weight loss through a reduction in calorie absorption.
Gastric-banding procedures involve wrapping a device around the stomach to create upper and lower pouches. A small upper pouch restricts food intake by limiting the amount of food that can be ingested at a sitting. Early banding devices, placed by open surgical technique, were not adjustable. Now, surgeons laparoscopically insert devices, such as the LAP-BAND®, which can be adjusted by changing the volume of the subcutaneous reservoir to control the degree of gastric constriction.4
With restrictive procedures, such as gastric banding or vertical-banded gastroplasty, weight loss is lower and the failure rate is higher than with malabsorptive procedures.5,6 The typical gastric volume after vertical-banded gastroplasty is initially two ounces and may increase over time to approximately six ounces. At first, patients can consume only liquids and food particles no larger in diameter than a drinking straw. Unpleasant adverse effects, which usually result from not chewing well, overeating, or eating too quickly, may include vomiting and choking. Consequently, patients may alter their food choices to include high-calorie liquids, which may impede weight loss.7

The human body has about 20 feet (seven meters) of small intestine. The earliest malabsorptive weight-loss procedure, the jejunoileal bypass, left about 12 inches of small intestine for digestion. This procedure, which resulted in many late complications, has not been performed for about 20 years. However, early surgical failures led to the recognition of obesity as a chronic disease that requires longer-lasting procedures, rather than temporary measures that can be reversed after desired weight loss.

Today, the majority of weight-loss procedures combine gastric restriction and malabsorption measures, accounting for the volume of food consumed as well as how much intestinal mucosa is available for digestion and caloric absorption. The most common weight loss surgery procedure is the Roux-en-Y gastric bypass. One variation includes closing off the unused stomach portion with an incision; another detaches the stomach completely, so that it remains free-floating. The length of bypassed small intestine varies from 10 inches to 10 feet, averaging two to five feet.3 Surgeons perform the Roux-en-Y gastric bypass by both traditional open and laparoscopic techniques; a newer laparoscopic technique produces shorter recovery times and fewer postoperative complications.5 When performed by surgeons adept at laparoscopy, operative time and blood loss are less, critical care and entire hospitalization times are significantly shorter, and weight loss is not significantly different than when traditional open techniques are used.6


The most drastic weight loss surgery performed today is the biliopancreatic diversion (BPD). So far, it is the most effective procedure for prolonged weight management, with 72% of recipients maintaining healthy weight for 18 years.3 This procedure removes a portion of the stomach and reroutes food into a short segment of the ileum, known as the “common channel,” reducing the mixing of pancreatic secretions and bile with food. Malabsorptive procedures may cause adverse effects different from those incurred with restrictive surgery; patients may experience chronic diarrhea and “dumping syndrome,” a combination of symptoms after eating sweets that includes nausea, weakness, faintness, diaphoresis, and diarrhea immediately after eating. Fruits, often necessary sources of nutrients, can be particularly problematic for these patients because of their high sugar content.8
A variation of the biliopancreatic diversion, the duodenal switch, preserves the pyloric valve and some of the proximal duodenum. The small segment of the retained duodenum protects against ulcer formation and perforation. With biliopancreatic diversion-duodenal switch, most of the acid-producing fundus of the stomach is not simply stapled off and left behind, but removed. Biliopancreatic diversion-duodenal switch has the lowest incidence of dumping syndrome and produces the most weight loss of all procedures.8 Some surgeons have begun performing the procedure laparoscopically with a subsequent reduction in short-term postoperative complications.