Laparoscopic Roux-En-Y Gastric Bypass
How does the Gastric Bypass Work?
The two main principles behind this surgery are restriction and malabsorption. Similar to the gastric band, the gastric bypass also has restriction for which a small gastric pouch is created. People feel full quicker after eating, eat less food, take in less calories, and lose weight. Unlike the band, the restriction of the bypass is fixed meaning there is only one size gastric pouch after it is created.
Malabsorption is the second mechanism for the weight loss. The small bowel is re-routed, and the stomach and a segment of small bowel is bypassed with a long Roux Limb. Remember that food travels down the Roux Limb, and digestive juices from the bypassed stomach, pancreas, and liver will meet with this food later in the “common limb.” No digestion or absorption of calories occur until these meet in the common limb. Essentially, there is a shorter length of small bowel available to absorb calories hence less calories is taken up, and this further helps people will lose weight.
How is the Gastric Bypass done?
This surgery is also performed laparoscopically. A small gastric pouch is created to approximately 20 ml pouch- about the size of a golf ball. This step is performed by stapling and dividing the stomach and to separate it from the remaining stomach.
The small bowel is then divided further down from the remaining stomach. The divided end will be re-connected to the small gastric pouch created. The other divided end will be re-connected to the small bowel. The small bowel to small bowel connection forms a “Y” shape. The gaps that are formed from dividing this small bowel is closed to minimize chances of internal hernias.
After all the communications are created, a gastroscope is used to inspect the connection between the gastric pouch and small bowel from the inside of the bowel. A test for leaks is now performed under water to ensure a solid seal around this communication.
Advantages to the Gastric Bypass
The gastric bypass is the most frequently performed bariatric procedure, therefore it has been researched and studied the most over the years. The procedure has gone through many changes for improvements in efficiency and safety. When considering results, the gastric bypass will typically have a higher weight loss when compared to the gastric band. The excess weight loss can be as high as 60-80% with the gastric bypass. In addition, weight loss appears to be faster when compared to the gastric band. There is also a higher improvement and resolution rate for co-morbidities when compared to the gastric band.
Potential Risks of the Gastric Bypass
As with any other surgery, risk of death is always a possibility. The death rate is very low but higher than the gastric band with 1 out of 200 (0.5%). Again, almost all these reported deaths are usually secondary to the medical condition associated with obesity. In general, people who need the gastric bypass usually have more medical problems and are higher operative risk thus accounting for the higher complication rate, and higher death rate when compared to the gastric band.
Problems during the surgery itself are also very rare. Gastrointestinal leaks are the most worrisome problem that surgeons look out for the most. During the surgery, the anastomosis between the stomach pouch and small bowel is tested. Even after the surgery, typically many surgeons prefer to get an x-ray as patients swallow contrast to further check for a leak. Even checking serial labs to help detect leaks. Leaks do occur up to 4% of the time which may or may not need surgery for repair depending on various factors.
Long-term problems that could arise are marginal ulcers and anastomotic strictures. Both occur up to 5% of the time. Marginal ulcers are ulcers that form at the edge of the stomach and small bowel communication. Not uncommon because even though smaller, the stomach pouch still produces acid, and the lining of the small bowel is not accustom to the exposure of that much acid.
Anastomotic strictures is another issue to be aware of. With healing of marginal ulcers or normal healing and scarring at the stomach and small bowel anastomosis, the opening in this communication could narrow over time. Sometimes this could lead to people being unable to pass food through the communication resulting in nausea and vomiting. Typically this problem can be fixed with simple endoscopy and gentle dilation of the opening with a balloon. Rarely would surgery be required for revision.
Internal hernia is another problem that can occur in the short and long term. In the short term, it typically caused by gaps left open during the surgery allowing small bowel to slip in and get stuck. Although no common, but it does happen. In the long term, even if these gaps are properly closed in the original surgery, with great weight loss means fat loss around the small bowel and in the areas where these gaps were. With less fat in place, these areas open up and could potential trap small bowel - it happens, but no very often.
Because of malabsorption, there are other associated long term risks that people need to know. Deficiencies in fat soluble vitamins, folate, iron, calcium, and Vitamin B12 may occur. Scheduled lab work and in addition to any related symptoms will help identify deficiencies. Typically, supplementation will be all that’s required to fix these problems.
Regaining weight is a possibility, but unlikely if people are very conscious of the diet and behavioral modifications that helped them lose the weight after the surgery. Even if after the surgery, when people do everything that is expected, regaining weight can occur, but this weight will usually only be 5-10% of the weight that was lost - not the entire amount of weight lost.
People who have had the gastric bypass and try to cheat on their diets with high carbohydrates or simplesugars will suffer symptoms of “dumping syndrome.” Typically may feel abdominal bloating, cramping, and diarrhea. In addition, other symptoms include possibly nausea, vomiting, dizziness, and fatigue. Simple ways of correcting dumping syndrome is to avoid those foods and add more protein. Avoid drinking fluids during meals, but mostly 30 minutes before and after meals.
Keys to Good Outcomes in the Gastric Bypass
As with the gastric band, it is important to be consistent with the bariatric diet. But with the bypass, it is crucial on the timing of advancement in diet stages. The stages of the bariatric diet are explained in the later portion of this manual, but in general, advancement in the diet is much slower for the gastric bypass than the band. Logically, this would make sense. For instance, the first two weeks after the surgery is mostly liquids in the bypass, while after the first week in gastric bands, the diet already proceeds with puree foods. In the bypass, the stomach pouch and small bowel anastomosis is still healing - testing out the integrity of this sewn area too early could be catastrophic. In addition, the swelling and edema of this area will be more significant, therefore may only allow liquids to pass easily in the early period. Having the surgery with higher and quicker weight loss is no substitute for regularly scheduled exercise. The surgery limits the calories being taken in, but increasing metabolism to burn more calories even at rest is just as important. Fact - muscles taking up glucose out of the blood does not require insulin. Most people who have diabetes will therefore benefit with better glucose control. People who have the gastric bypass also have the advantage of a support system like the gastric band. Whether in formal groups with health professionals, or relying on family and friends to be around during the difficult times, having emotional and mental support is priceless beyond just success in weight loss.
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