For several decades, the gastric "bypass" surgery was the most popular surgery among the surgical options for the treatment of obesity and its comorbidities. Currently it is still considered the standard bariatric operation against which the rest of procedures are compared to.
It is an extremely safe operation that allows to achieve a pronounced loss of weight and that has an especially effective effect in terms of the control of diabetes mellitus. The procedure is carried out laparoscopically, that is, through small holes in the abdominal wall through which we introduce the instruments with which the operation is carried out. The minimally invasive (laparoscopic) technique allows surgery to be carried out in a highly efficient manner, minimizing trauma and manipulation of tissues. This results in a faster recovery, with less pain and a better cosmetic result for the patient. Similarly, the risk of some postoperative complications are reduced, such as infections and hernias of the surgical incisions. This technique generally allows the patient to ambulate and return to an active life more easily and in a shorter period of time than usual, thus reducing the risk of thrombosis and other significant complications.

The operation is carried out as follows:

• A new small stomach is formed, with an approximate capacity of 30 cc. At this stage, the new stomach is a small pocket with no outlet or continuity with the rest of the digestive system.
• The small intestine is divided several centimeters from its initial portion.
• The distal intestinal stump that results from this division is elevated and joins the small gastric pocket, thus reestablishing gastrointestinal continuity.
• The spaces resulting from intestinal reconfiguration are closed and the joints are tested to demonstrate their integrity and permeability.

What are the benefits associated with gastric bypass?

• With gastric bypass, you can expect to lose around 70 to 80% of excess weight.
• It is one of the most powerful procedures for the treatment of type 2 diabetes mellitus. Most of the patients achieve a total cure or a partial remission in the long term, most of the rest experience a significant improvement.
• Besides diabetes mellitus, many other diseases associated with obesity can remit partially or totally. Among them are: migraine, hypertension, dyslipidemia, asthma, pseudotumor cerebri, stress urinary incontinence, gout, joint and back pain, fatty liver, sleep apnea, gastroesophageal reflux, venous insufficiency (varicose veins), polycystic ovary syndrome, among many others.
• 95% of patients report a significant improvement in their quality of life.
• Potential improvement in terms of fertility.
• Years of life are gained (89% reduction in mortality at 5 years, between 8 and 13 years of gain in years of life).
• Significantly reduces cardiovascular risk (heart attacks and other diseases).
• Usually there is an improvement or resolution of depression and other psychosocial aspects, such as self-esteem, changes in self-perception of body image, etc.
• A wide range of other benefits.

In what way does this operation work on obesity and its diseases?

• By restrictive route: by reducing the capacity of the stomach, the amount of food that can be consumed is significantly reduced, this way the patient that undergoes this operation can only consume very small portions of food, reaching a sensation of full satiety very quickly.

• By malabsorptive route: by reconfiguring the intestinal anatomy, the foods that are usually unfolded and processed in an intact stomach and the first portion of the intestine, do not have contact with the enzymes produced by these organs until they have reached a very distal portion of the digestive system and therefore the nutrients and calories of what is consumed cannot be absorbed and used in their entirety, since the digestive process is shortened.

• By hormonal route: the stomach and intestine are complex organs that carry out different functions. Among them is the ability to release hormones that regulate various metabolic and digestive aspects. By creating the small gastric "pocket", most of the stomach is partially excluded from its digestive function. Consequently, a hormone, ghrelin, which is produced mainly in this region, significantly decreases its concentrations. This hormone is one of those responsible of generating the sensation of appetite. In this way, the patient not only cannot consume large portions, but also does not feel the desire to do so, which greatly facilitates weight loss. Other hormones such as PYY, CKK, GIP, GLP-1, leptin, adiponectin, among others, also see their participation modified due to intestinal reconfiguration. Some of these substances are responsible of the early and radical improvement seen in diabetes after undergoing a gastric bypass.

• Other mechanisms: there are other ways by which the postoperative gastric bypass patient loses weight and the diseases associated with it improve. These include the change in food preferences, the suppression of appetite via the central nervous system, the change in the intestinal bacterial flora, among many others.

What to expect from the procedure and hospital stay?

• The surgery is performed laparoscopically and lasts an average of 2 to 3 hours.

• Postoperative pain is generally not significant and is adequately controlled with commonly used pain relievers.

• It is started with oral fluids the day after surgery.

• The total hospital stay is one night on average

• The patient can ambulate from the day of surgery.

• It is usually possible to return to normal activities within the first 7 to 10 days after the procedure.