Gastric Bypass

Laparoscopic Gastric Bypass

The Roux-en-y gastric bypass is the procedure to which other obesity surgery is often compared. It is the most common obesity surgery performed and is considered by many as the “standard of care” in weight loss surgery. There are two varieties of roux-en-y procedures, the proximal and distal roux. The proximal bypass represents a more “restrictive procedure” in vastly limiting the amount of food a patient can eat while providing a more limited “malabsorptive procedure” that decreases the ability for food to be absorbed. The distal roux combines the small gastric pouch with a more lengthy bypass and thus a greater “malabsorptive procedure”.

Some of the difficulties of the roux-en-y have included the technical problems involved in creating the small gastric pouch located high in the abdomen near the gastro-esophageal junction. This is a more difficult area to reach surgically and can be challenging to make the small bowel extend to in certain individuals. Other problems have included the Roux stasis syndrome as described above, weight regain over time, and the technical difficulties involved in the revision of these procedures due to their location high in the abdomen and the associated scarring in this relatively confined region. By combining a moderate length distal bypass with a slightly elongated gastric pouch, the malabsorptive component of the procedure becomes more prominent and keeps the connection (anastomosis) between the stomach pouch and the small bowel more accessible in the abdomen should laparoscopic revision/reversal be considered.

 Click here to watch a video of the Gastric Bypass

How does the gastric bypass work?
Through the surgical creation of a small pouch out of a portion of the stomach, the patient is given a ”tool” to help him or her gain control over the feeling of hunger. Long-term weight control is dependent upon using this pouch/tool correctly, along with adopting a healthy lifestyle that includes good nutrition and exercise.

Initial weight loss (1 to 6 months) occurs because it does not take much food or liquid to fill the new small pouch. Therefore, satiety or “feeling full” is reached very quickly. Moderate to rapid weight loss occurs during this time but it is very important that the patient follow the recommended diet in order to stay healthy by taking in sufficient amounts of protein, vitamins, and minerals. It is critically important that the patient gets into the habit of living a healthy lifestyle during these months.

Not only is the amount of food intake reduced, but the types of food must be modified as well. Because the new pouch is small and some food can quickly pass through it into the newly attached small bowel, (the Roux limb, pronounced “Rew “) care must be taken to avoid high calorie items and in particular high concentration carbohydrates or sugars. This means some starches and all sweets, candies and cakes. If these foods reach the Roux limb the body will react by secreting a large amount of fluid into the Roux limb to try to dilute those carbohydrates. The result is abdominal cramping, diarrhea, sweating, light-headedness and sometimes fainting. This is the dumping syndrome and is not truly a complication but rather a byproduct of the new anatomy. The actual length of the patient’s gastrointestinal tract has been shortened as a result of the surgery as well but most patients have the ability to compensate for this loss of surface area over time by increasing the efficiency of the remaining small bowel.

Over time, some patients note a moderate increase in their appetite (6-12 months). The patient continues to maintain control over hunger by filling the pouch/tool with just enough nutritious food at each mealtime. By doing so, the pouch/tool actually stretches very slightly which signals stretch nerves to tell the brain to cut off feelings of hunger and replace them with feelings of fullness. Learning how to use your pouch correctly and long-term follow-up with the medical and nutritional support team are necessary for successful weight loss and management.

Back to Top

Advantages

  • A 2004 meta-analysis of more than 22,000 patients showed that those who underwent a bariatric surgical procedure experienced complete resolution or improvement of their co-morbid conditions including diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea.
  • 83.7 percent of type 2 diabetes cases were resolved.
  • In the studies analyzed, the control group that didn’t have bariatric surgery was at a higher risk for type 2 diabetes: 3.7 times higher.
  • Resolution of type 2 diabetes often occurred within days of the surgery.
  • 96.9 percent of hyperlipidemia cases were resolved.
  • 75.4 percent of hypertension cases were resolved; 87.1 percent were resolved or improved.
  • Substantial weight reduction occurred; 61.6 percent of excess weight was lost.
  • In 2000, a study of 500 patients showed that 96 percent of co-morbidities (the study looked specifically at back pain, sleep apnea, high blood pressure, type 2 diabetes, and depression) were improved or resolved.
  • A great deal of excess weight was lost, and patients experienced resolution of co-morbidities, and improved appearance, social opportunities, and economic opportunities.

Risks and Disadvantages

  • Because the duodenum and other sections of the small intestine are bypassed, poor absorption of iron and calcium can cause low total body iron and a greater chance of having iron-deficiency anemia. Patients who experience chronic blood loss during excessive menstrual flow or bleeding hemorrhoids should be aware of the chance of iron-deficiency anemia. Women already at risk for osteoporosis that can occur after menopause, should be aware of the possibility of increased bone calcium loss. By taking a multivitamin and calcium supplements, patients can maintain a healthy level of minerals and vitamins.
  • Bypassing the duodenum can cause metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back, and fractures of the ribs and hipbones. Eating foods rich in nutrients and taking vitamins can help patients avoid this.
  • Chronic anemia due to vitamin B12 deficiency may occur. The problem usually can be managed with vitamin B12 pills or injections.
  • A condition known as dumping syndrome can occur from eating too much sugar or large amounts of food. While it isn’t considered a serious health risk, the results can be very unpleasant. Symptoms can include vomiting, nausea, weakness, sweating, faintness, and on occasion, diarrhea. Some patients are unable to eat sugary foods after surgery.
  • The bypassed portion of the stomach, duodenum, and parts of the small intestine cannot be seen easily using X-ray or endoscopy if there are problems such as ulcers, bleeding, or malignancy.
  • It is thought of as a permanent, nonreversible procedure. In reality it can be reversed but it is difficult and can cause a different set of difficulties. The results after the reversal are not as the original anatomy.
  • This procedure, as any surgical procedure, could result in death.

A patient can develop deep venous thrombosis (a blood clot in the leg) that can be life-threatening. If the blood clot travels to the heart and lungs it can cause death. A leak from the sites where the bowel is reconnected can occur and this can cause severe infection and lead to death. Re-operation may be necessary for a number of reasons. Leaks, narrowing of the connection sites, bleeding, injury to other organs are some of the reasons re-operation may become necessary. The goal of the surgery is to perform a gastric bypass laparoscopically however there is no guarantee that the operation will be completed laparoscopically. If the procedure cannot be completed safely with the laparoscopic method an open technique may become necessary although our intention is to avoid an open technique if possible. There is no guarantee that the patient will lose as much weight as they wish and likewise there is no guarantee that the patient will not lose too much weight. Vitamin and mineral deficiencies are a very real danger and strict attention must be paid by both the patient and the medical doctor that follows the patient in the postoperative period.

Back to Top

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, continue to travel downstream into the first portion of the small bowel called the duodenum. It then combines 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, 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 are 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.

Back to Top

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 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.

 



>back to the top