How is the Laparoscopic Gastric Bypass performed?

Sophisticated laparoscopic surgery first became available around 1990 when small, lightweight, high-resolution video cameras were developed, allowing surgeons to “see” into the abdomen using a pencil thin optical telescope. Pictures from the video camera are projected on a TV monitor at the head of the operating table. The surgeon must develop skills in operating by this method without being able to feel tissue directly and by learning to determine where instruments are by seeing them on TV. The benefits of the laparoscopic approach come from the very small incisions that are made. Because of this, patients experience less pain and very little scarring. Patients are able to get up and walk within hours after surgery, can breathe easier, and move without discomfort. This decreases the risk of post-operative pneumonia, deep vein thrombosis, (blood clots) and pulmonary embolus, (blood clots to the heart and lungs). Without a single large incision the risk of wound infection and incisional hernia drops dramatically. Most people find they can return to normal activities within 10 to 12 days or sooner.

The gastric bypass is accomplished in three surgical steps. The first step is the creation of a small gastric pouch from the patient’s original stomach. The pouch size is approximately 30-40 cc or slightly more than two ounces. The pouch is somewhat like an extension of the esophagus but, when completed, is completely separated from the remainder of the stomach. The pouch is created along the more muscular side of the stomach and thus is less likely to stretch over time. This is the patient’s new stomach and because it is significantly smaller than the original stomach far less food can be stored here before becoming full. In this way the feeling of fullness occurs much earlier when the patient eats and far less is eaten for each meal. Most patients who have undergone the gastric bypass indicate that they are far less interested in food and that their appetite is vastly diminished. This can sometimes have a negative effect because it prevents the patient from taking in the necessary nutrition they require postoperatively. It is an example of how the gastric bypass changes a patient’s lifestyle forever and how it is a mistake to assume that once the surgery is completed that a patient will no longer have to put forth effort to maintain their health.

The next step in the procedure involves dividing the jejunum (the second segment of the small bowel) approximately 50-100 cm beyond its origin and connecting the bottom portion to the gastric pouch. Food now travels from the mouth to the esophagus, into the gastric pouch and then immediately into the jejunum or Roux limb. Food no longer goes to the larger portion of the stomach. None of the stomach is removed and the secretions from the remainder of the stomach, now called the gastric remnant, continued to travel downstream into the first portion of the small bowel, called the duodenum, and combine with juices from the pancreatic gland and the liver. (The gastric remnant remains in place and maintains an excellent blood supply; it’s just not used as a food reservoir any more). This combination of fluid is crucial for the digestion of fats and protein as well as complex carbohydrates. Until this combination of fluid combines with food this digestion cannot take place.

The third step in the procedure involves the reconnection of the bowel (the first 50-100 cm of the jejunum and the duodenum containing the juices from the stomach, pancreas, and liver and called the biliopancreatic limb) to the segment of small bowel that was connected to the gastric pouch (the Roux limb). It is the distance between the gastric pouch and the place where the biliopancreatic limb is connected that determines the length of the bypass and the degree of malabsorption created by the operation. This distance is selected based on the patients BMI. The average length of the small bowel before surgery is thought to be approximately 18 ft. with the jejunum accounting for the first 2/5 of the small bowel. The length of the Roux limb that is created ranges from 75 cm to 180 cm (3-6 ft). The average time it takes to complete the Laparoscopic Roux-en-Y Gastric Bypass is approximately 2 hours

In summary, food now travels from the esophagus to the now greatly limited gastric pouch and then to the Roux limb. As food travels through the Roux limb water and some carbohydrates are absorbed but very little digestion occurs until the food reaches the reconnection with the biliopancreatic limb. In some respects, the operation is equivalent to having the length of the Roux limb removed. A consequence of the surgery is that the absorption of food, minerals, and vitamins that once occurred in the duodenum and first portion of the jejunum is now lost. This is another element of the operation that must be taken into account and compensated for by the patient for the rest of their lives. This translates into vitamin and mineral supplementation indefinitely.

There are other mechanisms that seem to play a part in the new gastrointestinal arrangement but the exact way through which they work has not been identified clearly yet. There may be hormonal changes in the way the stomach, pancreas, and liver interact. The nervous system that controls appetite and the feeling of fullness may be changed as a result of the new anatomy and/or the hormonal responses that usually interact with the nervous system may be affected because of the new anatomy. An example of the effect of this altered arrangement is the often dramatic improvement in a diabetic patient’s control of their diabetes. This frequently occurs independently of the amount of weight lost and can be as rapid as 1-2 days in some patients. In a very few patients this response has occurred so dramatically that months later they have reported having too low a glucose level.

The gastric bypass provides an excellent tool for gaining long-term control of weight without the hunger or craving usually associated with small portions or with dieting. Weight loss of 50 to 90 percent of the excess body weight is achievable for many patients and long-term maintenance of weight loss is very successful--- but does require adherence to a behavioral regimen.

What gastric bypass surgery is not:

The gastric bypass is not a one-time visit to the operating room and a means to lose weight without careful follow-up and an extensive lifelong program of nutritional health. The gastric bypass is a dangerous idea for anyone who is not committed to maintaining a healthy lifestyle after his or her surgery. The consequences of neglecting nutritional health postoperatively can be devastating. Vitamin and mineral deficiencies can occur and a lifelong commitment to avoiding these deficiencies by self-care and medical follow-up is crucial.