There are several variations of gastric bypass surgery, the most common being the Roux-en-Y bypass, named after the French surgeon who developed the surgical technique.
As mentioned previously, a gastric bypass combines the effects of restriction and malabsorption. A small stomach pouch is created, this time not by a band but by sectioning off the top portion of your stomach with a triple staple line. A new opening is then made from this pouch. The malabsorption effect is achieved by bypassing the first segment of your small intestine. The remainder of your small intestine is then joined to the new opening from your stomach pouch. The remainder of your stomach, which is now redundant, remains quite happily inside, and the enzymes and digestive juices produced in the upper part of your digestive tract enter your small intestine slightly lower down.
A gastric bypass operation is major surgery with permanent changes made to your digestive tract. Therefore the risks and benefits need to be weighed up carefully before a decision is made to proceed. The operation usually takes 1- 2 hours and is done either by open operation or laparoscopically (keyhole surgery). Not all patients are suitable for a laparoscopic procedure. Expect to spend 3-4 nights in hospital and be off work for up to six weeks.
WEIGHT LOSS EXPECTATIONS
As you would expect, because you are combining the effects of reducing the amount of food you can take in and absorbing fewer calories from the food you do eat, weight can be lost quite quickly and bypass patients lose on average 70% of their excess weight, most of which occurs in the first six months after surgery.
Because of the rapid weight loss, people who have obesity related health problems such as diabetes, high cholesterol or high blood pressure often see a rapid improvement or resolution of them. In fact, most patients are able to significantly reduce or even stop their medications for these illnesses after surgery.
RISKS AND SIDE EFFECTS
The risk of dying during or soon after a gastric bypass is about 1:100 patients. The major cause of death is the development of a blood clot in your lungs (pulmonary embolism) and so as with all obesity surgery patients we give you drugs before and after surgery to thin your blood and get you out of bed soon after the operation. There are a lot of internal stitches and staples in your stomach and intestines and one of the seams could leak, requiring on some occasions a return to theatre in the first few days for a second operation to repair it.
Because your digestive tract has been altered, it is more prone to strong reactions to the foods you eat. You need to allow your body at least three months after surgery to adapt to your new digestive pathway. Some days you will be able to eat a particular food without problem and the next time you try occasions a return to theatre in the first few days for a second operation to repair it.
Because your digestive tract has been altered, it is more prone to strong reactions to the foods you eat. You need to allow your body at least three months after surgery to adapt to your new digestive pathway. Some days you will be able to eat a particular food without problem and the next time you try it, it will cause nausea - there is no obvious explanation for why this occurs. An unpleasant effect called “dumping” occurs if you overdo the sugar in your food; too much fat can also be disturbing. Occasionally longer term side effects such as stomach pouch dilatation or tightening of the stoma (opening) between your stomach and intestine need remedial surgery, but these are quite rare and once they have settled down after your surgery, most people do not experience any problems long-term.
Because your food absorption is altered, post-operatively we regularly check your blood vitamin and mineral levels to ensure you do not develop any deficiencies. Everyone takes a daily multivitamin tablet and about a third of patients will also need additional supplements (eg. calcium, iron or vitamin B12).
Despite all the best management, a small number of people will fail to lose weight even with a gastric bypass. Further modifications to increase the amount of malabsorption are possible but raise the risk:benefit ratio to the patient significantly and are not undertaken lightly.
