The American Society for Bariatric Surgery estimates that more than 140,000 people had weight-loss surgery in 2004. Bariatric procedures can either reduce stomach volume, limiting the patient's ability to consume food, or they can alter the digestive process, curbing the amount of calories that the patient can absorb. Here's a rundown of six bariatric procedures, from the most popular to the most experimental.

Roux-en-Y gastric bypass
Many bariatric surgery experts consider Roux-en-Y gastric bypass (RYGB) to be the premier weight loss surgery, claiming that it offers the most excess weight loss over time with an acceptable level of risk. Most of these procedures are now performed laparoscopically and require an inpatient stay of one or two days. At Baylor University Medical Center in Dallas, bariatric surgeon Todd McCarty, MD, leads a team of six surgeons who perform about 1,100 laparoscopic RYGB procedures every year. What's most remarkable about Baylor's cases is that 92 percent of these patients leave within 23 hours after surgery.

Laparoscopic RYGB requires four or five incisions and takes about one hour. Dr. McCarty performs the procedure as follows: First, he creates a proximal stomach pouch, which holds about 30ccs. He then divides the upper jejunum, brings it up in front of the colon (an antecolic approach) and connects it to the stomach pouch (this section of the intestine is called the Roux limb). He then connects the end of the jejunum to the side of the Roux limb. Food passes through the esophagus, into the upper pouch, through the anastamosis and into the Roux limb. Digestive juices from the stomach, the liver and the pancreas pass through the duodenum and the jejunum and mix with the food in the Roux limb where the parts of the small intestine are attached. The food and the digestive juices then pass through the rest of the intestine.

Over the past few months, Baylor University surgeons have been doing more revisional Roux-en-Y procedures, particularly for patients who have had laparoscopic adjustable gastric band (Lap-Band) surgery, notes Dr. McCarty. "Some patients opt for the band at first, but they don't achieve enough long-term weight loss and eventually elect to undergo bypass surgery," he says. He points out that because the Lap-Band has only been FDA-approved for 3.5 years, there are no long-term U.S. studies, and he questions the accuracy and quality of international studies that seem to demonstrate sustained long-term weight loss comparable to bypass.

On the other hand, he points out, U.S. studies that have followed gastric bypass patients for 17 years show that, in general, they end up losing twice as much weight as patients who undergo laparoscopic adjustable gastric banding (although there haven't been any long-term U.S. studies directly comparing the two procedures). The long-term studies on laparoscopic RYGB helped lead to the American Medical Association's decision to assign a CPT code to the procedure in January 2005; the Lap-Band, although it is FDA-approved, has an investigational code.

Dr. McCarty also counters the critics of lap RYGB who call it invasive and extreme. "We can do the procedure with five incisions, the same as Lap-Band surgery, and we've reduced the risk of bowel obstruction, staple-line failures, gastro-jejunal anastomotic strictures, wound infection and pulmonary complications to less than one percent," he says. Also, the RYGB doesn't leave the patient with a device permanently wrapped around the stomach.

Dr. McCarty has developed a surgeon training program and proctors surgeons around the country in laparoscopic RYGB, and he believes that in the near future, most of his patients will recover within 23 hours.

Laparoscopic adjustable gastric band (Lap-Band)
This surgery involves placing an adjustable silicone band around the stomach to decrease the amount of food it will hold. The band is adjusted by injecting saline into an access port that lies next to the abdominal wall; as it tightens around the stomach, less and less food can enter. Consequently, patients feel fuller faster, and because the majority of the digestive tract is left intact, food is absorbed normally through the intestines. The only FDA-approved LAGB is the Lap-Band, which is manufactured by Inamed and was approved in 2001. Another LAGB, the Swedish adjustable gastric band, has been used internationally but is not yet available in the United States.

At the Northwest Weight Loss Surgery Center in Kirkland, Wash., surgeons Kevin Montgomery, MD, and Brad Watkins, MD, perform nearly 400 Lap-Band surgeries annually. The procedure takes about 45 minutes to an hour and uses five small incisions. The surgeons place the band around the top part of the stomach to create a 20-cc pouch and secure it by suturing the lower wall of the stomach to the upper stomach, creating a tunnel of tissue that holds the band in place. They then suture the access port to the muscle under the fat layer of the abdominal wall. Patients recover for about an hour after surgery before returning home the same day; they generally return to normal activity within three to seven days.

For some patients, simply having the band in place results in a steady one- to two-pound weight loss for a few months. As soon as they begin to plateau (usually after four weeks to six weeks), they receive their first adjustment. The band is filled with 0.1cc to 4ccs of saline at a time, depending on the size of the band and the patient's needs. Patients generally receive two to six adjustments in the first year and lose an average of 49 percent of their excess weight.

Dr. Watkins and Montgomery note that RYGB patients may tend to lose weight faster initially, but some studies suggest that after two or three years, Lap-Band patients tend to catch up. Furthermore, they say, Lap-Band patients continue to lose weight every year, while RYGB patients can plateau. The surgeons stress that the key to consistent, long-term weight loss with the Lap-Band is quality aftercare. Too often, surgeons don't monitor their patients soon enough or closely enough and fail to adjust the band when weight loss slows, leading to less-than-optimal results.

Although the Lap-Band does carry some risks, including prolapsed or slipped bands, port-related complications and band erosion, these surgeons say that the procedure is safer than RYGB. Most importantly, it causes no long-term metabolic problems, such as vitamin deficiencies, muscle wasting and bone disease, which can occur in RYGB patients because of the bypass component of these procedures. Even if a gastric bypass patient achieves a healthy weight, the malabsorption problems will remain, they point out. Also, the band can be removed completely if necessary, leaving the patient with a completely normal digestive tract.

Drs. Watkins and Montgomery are starting to do revisional Lap-Band surgery on patients who've had gastric bypass and stomach stapling procedures and have stretched out the stomach to the point that they're no longer losing weight. In this case, the only way to decrease the stomach size is to revise the bypass or implant a band.

The surgeons are developing an adolescent program, which will begin in the next few months. Because the band isn't approved for patients under 18, they'll be doing the procedures as a part of a research study involving two other sites at New York University and the University of Chicago. They're also building an ambulatory surgery center, which will open this summer.

Over time, these surgeons believe, the Lap-Band will gradually gain favor, even among surgeons who primarily do gastric bypass. The surgery's safety profile, shorter recovery process and long-term results may eventually make it the premier weight loss surgery, they say.

Biliopancreatic diversion with duodenal switch
This is a variant of biliopancreatic diversion that offers some of the advantages of that procedure without some of the associated problems. A larger portion of the stomach is left intact, including the pyloric valve (through which food passes from the stomach into the small intestine) and the initial segment of the duodenum. The small intestine is then divided to separate the flow of food from the flow of biliopancreatic juices. The contents from these two segments meet in the common channel. The duodenal switch component helps reduce the incidence of stomal ulcer, allows for more normal food absorption and eliminates dumping syndrome, in which food moves too quickly through the digestive system, causing nausea, weakness, fainting and diarrhea.

This procedure is the third most common bariatric operation performed in the United States, according to Harvey Sugerman, MD, president of the American Society for Bariatric Surgery, and it can lead to 75 percent to 85 percent excess weight loss. However, because it is so complex and carries a high risk of metabolic problems, it's usually reserved for superobese patients.

Biliopancreatic diversion (Scopinaro procedure)
This is a malabsorptive procedure that involves removing a major portion of the stomach and rearranging the intestinal tract by creating an alimentary tract for the passage of food, a biliary tract for the passage of biliopancreatic juices and a common tract, where the food and biliopancreatic juices mix before entering the colon. The short alimentary tract prevents nutrients from being completely absorbed. The short common limb allows biliopancreatic juices to mix with food for only a short time, which limits the absorption of fat. The procedure can be done with an open or laparoscopic approach.

Biliopancreatic diversion can lead to significant long-term weight loss, but it's fallen out of favor in the United States because it can cause severe metabolic problems, including anemia, protein malnutrition and osteoporosis.

Vertical banded gastroplasty
This procedure involves partitioning the stomach vertically with a line of staples, creating a small pouch along the inner curve of the stomach. The outlet of the stomach pouch is narrowed with a band by removing a plug of the stomach, threading the band through the window, and stapling the band to itself. The band slows the rate at which food empties from the stomach, allowing patients to feel fuller longer. The rest of the digestive tract is left intact.

Although vertical banded gastroplasty used to be a very common, Dr. Sugerman says that it's rarely performed today. Over time, the staple line can break down or the stomach pouch can stretch, necessitating a revisional operation. Other possible complications include esophageal reflux and dilation or obstruction of the stoma.

Implantable gastric stimulator (gastric pacemaker)
This pacemaker-like device, made by Transneuronix, was first studied in the 1990s in Italy and is currently undergoing FDA trials. It consists of a pocket-watch sized, battery-operated electrical pulse generator, which is implanted in the abdomen. The generator delivers electrical pulses to a thin, insulated lead, which is implanted in the stomach wall. After the surgery, which is performed laparoscopically and lasts about an hour, the device is controlled by an external handheld programmer, which can check the function of the pulse generator and change the electrical signals. About every five years, patients must undergo a simple surgical procedure to replace the generator's battery.

When the gastric stimulator delivers the electrical pulses to the stomach, it activates numerous feedback mechanisms between the stomach and the brain, causing the patient to feel full, says Steve Adler, Transneuronix's executive vice president.

The device is approved in Europe and Canada, and according to Mr. Adler, it has not been associated with any major complications or deaths. Clinical trials have shown that patients can achieve 45 percent excess weight loss over two years.

The gastric stimulator isn't for everyone, however. Patients who are binge eaters can choose to ignore the feeling of fullness and overeat. The company has developed screening tests that patients must complete to ascertain whether or not they will be successful with IGS therapy.

Measuring success
As surgeons continue to refine bariatric surgery techniques and develop new ones, they will continue to have one thing in common - they are all tools for weight loss, not complete solutions. For any of these procedures to be ultimately successful, patients must agree to change eating and exercise habits and adopt entirely new lifestyles, and surgeons must commit to providing long-term post-operative support.