The American Society for Bariatric Surgery describes two basic approaches that weight loss surgery takes to achieve change:
- Restrictive procedures that decrease food intake.
- Malabsorptive procedures that alter digestion, thus causing the food to be poorly digested and incompletely absorbed so that it is eliminated in the stool.
- A combination of 1 & 2, such as the Roux-en Y gastric bypass
- Other surgical options are: "duodenal switch" or Laparoscopic Adjustable Gastric Banding.
Laparoscopic or Minimally Invasive Surgery
For the last decade, laparoscopic procedures have been used in a variety of general surgeries. Many people mistakenly believe that these techniques are still "experimental." In fact, laparoscopy has become the predominant technique in some areas of surgery and has been used for weight loss surgery for several years. Although few bariatric surgeons perform laparoscopic weight loss surgeries, more are offering patients this less invasive surgical option whenever possible.
When a laparoscopic operation is performed, a small video camera is inserted into the abdomen. The surgeon views the procedure on a separate video monitor. Most laparoscopic surgeons believe this gives them better visualization and access to key anatomical structures.
The camera and surgical instruments are inserted through small incisions made in the abdominal wall. This approach is considered less invasive because it replaces the need for one long incision to open the abdomen. A recent study shows that patients having had laparoscopic weight loss surgery experience less pain after surgery resulting in easier breathing and lung function and higher overall oxygen levels. Other realized benefits with laparoscopy have been fewer wound complications such as infection or hernia, and patients returning more quickly to pre-surgical levels of activity.
Laparoscopic procedures for weight loss surgery employ the same principles as their "open" counterparts and produce similar excess weight loss. Not all patients are candidates for this approach, just as all bariatric surgeons are not trained in the advanced techniques required to perform this less invasive method. The American Society for Bariatric Surgery recommends that laparoscopic weight loss surgery should only be performed by surgeons who are experienced in both laparoscopic and open bariatric procedures.
In recent years, better clinical understanding of procedures combining restrictive and malabsorptive approaches has increased the choices of effective weight loss surgery for thousands of patients. By adding malabsorption, food is delayed in mixing with bile and pancreatic juices that aid in the absorption of nutrients. The result is an early sense of fullness, combined with a sense of satisfaction that reduces the desire to eat.
According to the American Society for Bariatric Surgery and the National Institutes of Health, Roux-en-Y gastric bypass is the current gold standard procedure for weight loss surgery. It is one of the most frequently performed weight loss procedures in the United States. In this procedure, stapling creates a small (15 to 20cc) stomach pouch. The remainder of the stomach is not removed, but is completely stapled shut and divided from the stomach pouch. The outlet from this newly formed pouch empties directly into the lower portion of the jejunum, thus bypassing calorie absorption. This is done by dividing the small intestine just beyond the duodenum for the purpose of bringing it up and constructing a connection with the newly formed stomach pouch. The other end is connected into the side of the Roux limb of the intestine creating the "Y" shape that gives the technique its name. The length of either segment of the intestine can be increased to produce lower or higher levels of malabsorption.
- The average excess weight loss after the Roux-en-Y procedure is generally higher in a compliant patient than with purely restrictive procedures.
- One year after surgery, weight loss can average 77% of excess body weight.
- Studies show that after 10 to 14 years, 50-60% of excess body weight loss has been maintained by some patients.
- A 2000 study of 500 patients showed that 96% of certain associated health conditions studied (back pain, sleep apnea, high blood pressure, diabetes and depression) were improved or resolved.
- Because the duodenum is bypassed, poor absorption of iron and calcium can result in the lowering of total body iron and a predisposition to iron deficiency anemia. This is a particular concern for patients who experience chronic blood loss during excessive menstrual flow or bleeding hemorrhoids. Women, already at risk for osteoporosis that can occur after menopause, should be aware of the potential for heightened bone calcium loss.
- Bypassing the duodenum has caused metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back and fractures of the ribs and hip bones. All of the deficiencies mentioned above, however, can be managed through proper diet and vitamin supplements.
- A chronic anemia due to Vitamin B12 deficiency may occur. The problem can usually be managed with Vitamin B12 pills or injections.
- A condition known as "dumping syndrome " can occur as the result of rapid emptying of stomach contents into the small intestine. This is sometimes triggered when too much sugar or large amounts of food are consumed. While generally not considered to be a serious risk to your health, the results can be extremely unpleasant and can include nausea, weakness, sweating, faintness and, on occasion, diarrhea after eating. Some patients are unable to eat any form of sweets after surgery.
- In some cases, the effectiveness of the procedure may be reduced if the stomach pouch is stretched and/or if it is initially left larger than 15-30cc.
- The bypassed portion of the stomach, duodenum and segments of the small intestine cannot be easily visualized using X-ray or endoscopy if problems such as ulcers, bleeding or malignancy should occur.
Vertical Sleeve Gastrectomy
The Vertical Gastrectomy procedure (also called vertical Sleeve Gastrectomy, Greater Curvature Gastrectomy, Parietal Gastrectomy, Gastric Reduction and even Vertical Gastroplasty) generates weight loss by restricting the amount of food that can be eaten (removal of stomach or vertical gastrectomy) without any bypass of the intestines or malabsorption. The stomach pouch is usually made smaller than the pouch used in the Duodenal Switch.
Of the procedures that are currently performed for the treatment of obesity, it is ideal for patients who have very high medical risk, high weight or BMI, complex surgical histories or those who are fearful of potential complications from an intestinal bypass. It is also ideal for lower BMI patients who wish to avoid a more complex intestinal bypass or the possibility of vitamin or nutritional deficiencies secondary to procedures which cause malabsorption. Patients interested in Gastric Banding may also want to consider this procedure, since it avoids the foreign body issue of a Band. Patients using anti-inflammatory medications also should consider this procedure because ulcer risk is probably less than after gastric bypass or band procedures.
Restriction (Vertical Gastrectomy): The stomach is restricted by dividing it vertically and removing more than 85 percent of it. This part of the procedure is not reversible. The stomach that remains is shaped like a thin banana and measures from 2-5 ounces (60 - 150cc) depending on the surgeon performing the procedure. The nerves to the stomach and the outlet valve (pylorus) remain intact with the idea of preserving the functionsof the stomach while reducing the volume. By comparison, in a Roux-en-Y gastric bypass, the stomach is divided, not removed, and the pylorus is excluded. The Roux-en-Ygastric bypass stomach can be reconnected (reversed) if necessary.
Note that there is no intestinal bypass or malabsorption with this procedure, only stomach reduction.
- Stomach volume is reduced, but it tends to function normally so most food items can be consumed in small amounts.
- Eliminates the portion of the stomach that produces the hormones that stimulates hunger (Ghrelin).
- No dumping syndrome because the pylorus is preserved.
- Minimizes the chance of an ulcer occurring.
- By avoiding the intestinal bypass, the chance of intestinal obstruction (blockage), anemia, osteoporosis, protein deficiency and vitamin deficiency are almost eliminated.
- Very effective as a first stage procedure for high BMI patients (BMI >55 kg/m2).
- Limited results appear promising as a single stage procedure for low BMI patients (BMI 35-45 kg/m2).
- Appealing option for people with existing anemia, Crohn’s disease and numerous other conditions that make them too high risk for intestinal bypass procedures.
- Can be done laparoscopically in patients weighing more than 500 pounds.
Adjustable Gastric Band
The Adjustable Gastric Band was designed and developed with your safety and comfort in mind. The band is a strong, flexible silicone structure made entirely of biocompatible materials. With the Adjustable Gastric Band, weight loss occurs at a natural and healthy rate— ranging from 1- 2 pounds per week.
The Adjustable Gastric Band divides the stomach into two parts: a small upper pouch and a lower stomach. The adjustable band is placed around the top part of the stomach, which is the part containing the nerves that tell the brain, "Enough already!" A tube is attached to a port, which is sutured into the abdominal wall a few inches up and to the right of the belly button. The surgeon can adjust the tightness of the band by injecting saline into the port. At this time, the width of the stomach, or opening, between the two parts of my stomach, is about that of a pencil eraser. The upper pouch can only hold about 4 ounces (1/2 cup) of food. For this reason, you will feel full sooner and longer than usual. To maximize the benefits of the Adjustable Gastric Band, you should eat several small nutritionally balanced meals each day. Remember it will still be important to eat foods that are low in calories, fat, cholesterol, and sugar. Also: Remember to chew slowly and take smaller bites, include protein in your meals which will help you feel full longer. Avoid high-calorie drinks. Drink more water. Your healthcare team will give you advice regarding the large variety of foods that is appropriate to maintain healthy and balanced nutrition. Ensuring your success with the Adjustable Gastric Band requires hard work, dedication to your new lifestyle, and support from your loved ones.
Malabsorptive Procedures - Biliopancreatic Diversion
While these operations also reduce the size of the stomach, the stomach pouch created is much larger than with other procedures. The goal is to restrict the amount of food consumed and alter the normal digestive process, but to a much greater degree. The anatomy of the small intestine is changed to divert the bile and pancreatic juices so they meet the ingested food closer to the middle or the end of the small intestine.With the three approaches discussed below, absorption of nutrients and calories is also reduced, but to a much greater degree than with previously discussed procedures. Each of the three differs in how and when the digestive juices (i.e., bile) come into contact with the food.
Since food bypasses the duodenum, all the risk considerations discussed in the gastric bypass section regarding the malabsorption of some minerals and vitamins also apply to these techniques, only to a greater degree.
Biliopancreatic Diversion (BPD)
BPD removes approximately 3/4 of the stomach to produce both restriction of food intake and reduction of acid output. Leaving enough upper stomach is important to maintain proper nutrition. The small intestine is then divided with one end attached to the stomach pouch to create what is called an "alimentary limb." All the food moves through this segment, however, not much is absorbed. The bile and pancreatic juices move through the "biliopancreatic limb," which is connected to the side of the intestine close to the end. This supplies digestive juices in the section of the intestine now called the "common limb." The surgeon is able to vary the length of the common limb to regulate the amount of absorption of protein, fat and fat-soluble vitamins.
Biliopancreatic Diversion with "Duodenal Switch"
This procedure is a variation of BPD in which stomach removal is restricted to the outer margin, leaving a sleeve of stomach with the pylorus and the beginning of the duodenum at its end. The duodenum, the first portion of the small intestine, is divided so that pancreatic and bile drainage is bypassed. The near end of the "alimentary limb" is then attached to the beginning of the duodenum, while the "common limb" is created in the same way as described above.
- These operations often result in a high degree of patient satisfaction because patients are able to eat larger meals than with a purely restrictive or standard Roux-en-Y gastric bypass procedure.
- These procedures can produce the greatest excess weight loss because they provide the highest levels of malabsorption.
- In one study of 125 patients, excess weight loss of 74% at one year, 78% at two years, 81% at three years, 84% at four years, and 91% at five years was achieved.
- Long-term maintenance of excess body weight loss can be successful if the patient adapts and adheres to a straightforward dietary, supplement, exercise and behavioral regimen.
- For all malabsorption procedures there is a period of intestinal adaptation when bowel movements can be very liquid and frequent. This condition may lessen over time, but may be a permanent lifelong occurrence.
- Abdominal bloating and malodorous stool or gas may occur.
- Close lifelong monitoring for protein malnutrition, anemia and bone disease is recommended. As well, lifelong vitamin supplementing is required. It has been generally observed that if eating and vitamin supplement instructions are not rigorously followed, at least 25% of patients will develop problems that require treatment.
- Changes to the intestinal structure can result in the increased risk of gallstone formation and the need for removal of the gallbladder.
- Re-routing of bile, pancreatic and other digestive juices beyond the stomach can cause intestinal irritation and ulcers.