Gastric Bypass Surgery
Gastric bypass surgery is the most commonly performed surgical procedure for weight loss in the United States. The operation is major gastrointestinal surgery that permanently and substantially alters the stomach and intestines. The gastric bypass procedure yields impressive weight loss results, however, it is not performed for aesthetic reasons. It is used to treat morbid obesity and obesity co-morbidities through food restriction and malabsorption, helping significantly overweight individuals achieve lasting weight loss and improved health.
Overview of Gastric Bypass Surgery
Gastric bypass surgery is a term describing any of the various forms of weight loss surgery that involve reducing stomach size and bypassing a portion of the small intestine. All forms are similar in that a large portion of the stomach is sectioned off to reduce the amount of food that can be eaten and the small intestine is divided and rerouted to reduce the absorption of calories.
Combination Restrictive and Malabsorptive Procedure
Gastric bypass surgery uses both a restrictive and malabsorptive approach to weight loss.
- A restrictive procedure is one that limits the amount of food that can be eaten at any one time. In gastric bypass surgery, this is done by creating a new smaller stomach that forces smaller meal portions.
- A malabsorptive procedure is one that reduces the amount of food absorbed by the digestive system. In gastric bypass surgery, this is done by bypassing the upper portion of the small intestine. Since the food passes thru less of the intestines where digestion takes place, food is only partially digested and there is less absorption of nutrients and calories.
Roux-en-Y Gastic Bypass
When first developed the late 1960's, gastric bypass surgery used a loop bypass with a larger stomach. The loop configuration resulted in bile reflux, however, and the operation was modified into the Roux-en-Y (RNY) configuration that is popular today. With Roux-en-Y gastric bypass, a limb of the small intestine is attached to a very small stomach pouch. This form, unlike the initial loop configuration, prevents bile from entering the upper part of the stomach and esophagus. The remaining stomach and first portion of the small intestine are bypassed.
The Roux-en-Y is now the most common variation of gastric bypass surgery. It has been proven in numerous studies to result in durable weight loss and an improvement in health problems associated with obesity. Although not without risk, the results have earned it the distinction as the gold standard for bariatric surgery. The procedure has been accepted by most weight loss doctors and insurance companies as an effective treatment for morbid obesity when diets and exercise fail.
In Roux-en-Y gastric bypass surgery, the stomach is separated into a smaller, upper pouch and a larger, lower section, and the small intestine is divided and rerouted. The new smaller stomach pouch is created at the top of the stomach where the food enters from the esophagus using surgical staples to completely separate it from the lower portion of the stomach. The remaining larger, lower portion of the stomach is bypassed but not removed from the body.
Then, the lower portion of the small intestine is attached to the new stomach pouch. The upper part of the small intestine is bypassed in the digestion process. Since the natural stomach outlet is located in the cutaway portion of the stomach it is also bypassed, so a new stomach opening called a stoma is created at the connection between the new stomach pouch and reattached small intestine.
Advantages to Gastric Bypass Surgery
- More rapid weight loss following surgery than with purely restrictive methods
- Smaller stomach limits amount of food that can be eaten at any one time
- Intestinal rerouting limits amount of calories absorbed by the body
- Intake of sweets controlled because of Dumping Syndrome
- Resolves and/or improves certain obesity-related health conditions as weight loss occurs
Disadvantages to Gastric Bypass Surgery
- Complex operation, surgery risks include infection, leaks, and blood clots
- Vitamin and mineral deficiencies, can lead to metabolic bone disease and anemia
- May experience ulcers, bowel obstruction, or reflux
- Dumping Syndrome
Dumping Syndrome, which can cause nausea, diarrhea, and weakness, occurs when sweets enter the bloodstream too quickly. Gastric bypass surgery can cause dumping syndrome because the digestive system has been altered and foods enter the intestines more quickly. Dumping syndrome controls the intake of sweets and high calorie foods. It is considered both an advantage and disadvantage of gastric bypass surgery.
Patient Criteria for Gastric Bypass Surgery
Gastric bypass surgery is only recommended for morbidly and severely obese individuals (at least 100 pounds overweight for men and 80 pounds overweight for women) who are willing to make the necessary lifelong changes in diet, nutrition and exercise and have failed to lose weight under a medically supervised diet and exercise program. Because the procedure drastically alters the body, it should only be considered a last resort treatment for obesity. Patients who want to lose weight should discuss their weight loss options with their doctor who is in the best position to evaluate their health and make a recommendation for gastric bypass surgery.
Proximal vs Extended (Distal) Gastric Bypass Surgery
The length of either section of the intestine can be made longer or shorter to affect the levels of absorption. When a shorter length of intestines is bypassed it is called a proximal Roux-en-Y gastric bypass; when more of the intestines is bypassed it is referred to as an extended (distal) Roux-en-Y gastric bypass.
The most commonly performed procedure is the proximal Roux-en-Y gastric bypass. This is considered an effective operation for weight loss, even though some weight regain may occur over the first five years after surgery. Typically, weight loss occurs quickly during the first six months and peaks at 18-24 months.
The distal Roux-en-Y gastric bypass incorporates a greater amount of malabsorption, which leads to more permanent weight loss. However, as it may also result in more severe nutritional deficiencies, it is performed in very few patients. It is usually reserved for select individuals who are super obese, or more than 200 pounds overweight.
Open vs Laparoscopic Gastric Bypass Surgery
Gastric bypass surgery can be performed using either open surgery methods or minimally-invasive laparoscopic techniques. Open gastric bypass is performed through a single large abdominal incision held apart with abdominal wall retractors, whereas laparoscopic gastric bypass is performed through 5-6 small abdominal incisions using special surgical instruments.
Laparoscopic surgery has many advantages, including fewer wound complications, less intraoperative blood loss, reduced postoperative pain, quicker healing and recovery, and shorter hospitalization.
Laparoscopic surgery is not always the preferred method, however, and open surgery continues to be used in many situations. The use of one or the other often depends on the training and preference of the doctor as well as the medical status of the patient. Patients with an extremely high body mass, previous upper abdominal surgeries, or prior bariatric surgery may not be suitable candidates for laparoscopic surgery.
Long-term weight loss is similar between the open and laparoscopic operations, as the difference is primarily in the surgical method and not in the changes made to the stomach or intestines.
Gastric Bypass Variations
Mini Gastric Bypass - A variation of gastric bypass surgery that uses the simpler loop reconstruction of earlier procedures, but with some improvements. This form involves creating a long, narrow gastric pouch, then reconnecting the bottom portion to the side of the small intestine, bypassing 6 feet. The separated portion of the stomach, including the stomach outlet, and first portion of the small intestine remain in the body but are bypassed in the digestive process.
Fobi Pouch - This gastric bypass variation is similar to Roux-en-Y, with a few modifications, including a vertical rather than horizontal stomach pouch, the use of a silastic band at the new stomach outlet to simulate the pyloric valve and prevent stretching, reinforced staple line, and the placement of a stomach marker. This operation was devised by Dr. Mal Fobi, a prominent surgeon who has made many important contributions to the field of obesity surgery.
Life After Gastric Bypass Surgery
The changes to your digestion system are permanent and will affect your eating habits for the rest of your life. It is important to consider both the advantages and disadvantages of this procedure before making a decision.
Gastric bypass surgery will help a person lose weight, however, achieving lasting weight loss and improved health depends on a persons commitment to eating healthy and exercising on a regular basis. Diet will change to smaller portions, focused on healthy proteins and nutrient rich vegetables. Physical activity is important not only because it burns calories but because it helps protect and preserve muscle tissue during rapid weight loss. Nutritional supplements are required in order to provide the body with the vitamins and minerals it needs to survive. Periodic follow-up tests are necessary to monitor for nutritional deficiencies and long-term effects of weight loss surgery. Nutritional counseling and support groups will also play an important role in helping an individual adjust to the changes and life after gastric bypass surgery.