Bariatric Surgery

1. Weight/BMI Requirements

Before considering surgery for obesity, the patient must weigh at least 45 kg above their ideal weight (BMI greater than or equal to 40 kg/m2). From that moment on, surgery must be considered as a treatment for a debilitating disease and not for cosmetic reasons.

They may also have a BMI between 35 and 40 kg/m2, if they already have associated problems deriving from their obesity.

However, surgery may be considered in other weight loss situations if it is determined that from a medical perspective there are sufficient reasons for weight loss and surgery is the only way to achieve it.

2. Having made several attempts to reduce weight, duly guided by the doctor, without success;

3. Pathologies

• Absence of severe pathologies that condition the surgical procedure;
• Some psychiatric pathologies may be a contraindication for surgery if they are not properly controlled or if agreement is not obtained from the treating psychiatrist.

Medical (non-surgical) treatment for clinically severe (morbid) obesity includes various combinations of low-calorie diets, behavioral modification, physical exercise and pharmacological agents. The biggest problem with this type of approach is its inability to maintain a reduced body weight in most obese patients, with a high incidence of ineffectiveness in sustaining a 10% weight loss over time with this type of treatment.

Due to the serious risks related to this degree of obesity, the relative low risk of surgical treatment and the ineffectiveness of medical or dietary interventions, as well as the severity of weight variations as a result of inefficient conservative treatments (yo-yo effect) , bariatric surgery has been asserting itself in this universe, due to the good results not only in reducing weight achieved and maintained, but also with the improvement of the diseases that accompany it.

To understand how surgical intervention helps you lose weight, it is important to have an understanding of how the digestive system works. Thus, food after chewing is ingested through the esophagus, which is nothing more than a long muscular tube entering the stomach. The stomach, which can normally contain quantities greater than 1500 ml of food, mixes it with hydrochloric acid and crushes the food bolus, passing it to the small intestine (duodenum), where it mixes with the remaining liver and pancreatic juices, where digestion continues and most of the nutrients are absorbed. The small intestine, which normally measures between 4.5 and 6 meters, is largely responsible for absorption.

As previously mentioned, food passes into the duodenum, mixing with bile and pancreatic juice. This area of the intestine is also largely responsible for the absorption of iron and calcium. The most distal segment of the small intestine, also called the ileum, plays an important role in the absorption of nutrients and in particular fat-soluble vitamins (A, D, E and K). When the contents of the ileum enter the colon, its consistency, which until now was liquid, becomes solid, due to the absorption of water that takes place in the colon.

The fundamental principle of obesity surgery is to change the energy intake/absorption-consumption relationship, which in obesity is favourable to the first set, thus causing an accumulation of energy, increasing weight. Therefore, reducing food intake or absorption and increasing physical activity will cause weight loss by changing this dynamic.

In summary, bariatric surgery can control weight by altering energy balance in two ways:

1. Reduce the amount of food you eat (restriction);

AND/OR

2. Cause part of the food to not be digested and completely absorbed (malabsorption), being eliminated through faeces;

Weight loss with surgery is not the same for all patients in the same way, it varies according to several factors: age, initial weight, ability to exercise, intake of sweets, type of surgery performed, etc. On average, patients lose between 30% and 40% of their initial weight between 12 and 18 months. However, in heavier people, weight loss tends to be more prolonged.

Obesity surgery through Roux-en-Y Gastric Bypass is the prototype of gastric restriction combined with malabsorption. It is one of the most frequently carried out operations in the world. The stomach is divided either with mechanical or manual sutures, to obtain a small reservoir (+/- 15 ml), the size of restrictive surgeries.

After this complete division of the stomach, the small intestine divides to connect the gastric reservoir to the intestine and the other sectioned part of the intestine connects again to the intestine, thus forming a loop in Greek (Y), starting the absorption of food only from this union of intestine with intestine (common loop).

Therefore, a large area for grinding and absorbing food is bypassed (stomach, duodenum and part of the small intestine). This malabsorption may be greater or lesser depending on the size of the intestinal loops that lie before the union of the two loops, however, the greater the malabsorption established, the greater the risk of side effects.

Discover the case of Elisangela, who lost 35 kg after bariatric surgery with gastric bypass: Gastric Bypass Before and After

Discover the case of Cristina, who lost 40 kg also with gastric bypass: Bariatric Surgery Before and After

In specific cases, where there are contraindications regarding Gastric Bypass and Gastric Sleeve, the remaining stomach that would be excluded in gastric bypass is removed.

For several years it has been thought that, in patients with a high BMI (>60 kg/m2) or with serious associated diseases, there is an advantage in undergoing Roux-en-Y gastric bypass surgery or Biliopancreatic Bypass with duodenal switch. As the risk of post-operative complications in this group of patients is particularly high, it led some surgeons to initiate surgery that aimed to reduce the weight of these patients and at the same time reduce the risk of complications in the subsequent and definitive surgical process of weight loss, thus creating the so-called Vertical Gastrectomy or Gastric Sleeve.

Tubular gastrectomy is a purely restrictive operation, reducing the size of the gastric reservoir to a value between 60 and 100 mls. Another action thought to be attributable to it is the reduction in the plasma level of ghrelin (one of the hormones that regulates hunger), which could also be a mechanism involved in weight loss and not just restriction.

Indications for performing a linear gastrectomy alone include:

• Body Mass Index > 60 kg/m2
• Severe comorbid illnesses
• Advanced age
• Unfavorable anatomy such as liver cirrhosis, intense abdominal adhesion causing poor exposure.

In almost all existing studies, weight loss is established within a year, partly maintained in the first 3 years, but with a high disease recurrence rate.

The main complications of surgery are stomach fistula and haemorrhage.

The appearance of these processes to try to control weight was not the result of chance, but rather observations made by surgeons of operations carried out to treat other types of diseases, such as cancer and others, in which there was a need to remove part of the stomach or small intestine. The almost impossibility of maintaining weight and/or even increasing it with this type of surgical procedures led to the thought that with some modifications these surgeries could be applied to weight loss in morbid obesity.

It is very important to have an idea of how these surgeries work, because a lot has changed in recent years. Over the last few years we have learned that to control weight with surgery that only restricts food intake, it is necessary to create a reservoir in the upper part of the stomach, with a small initial capacity, ranging between 15 and 25 ml, and which connects to the rest of the stomach through a stoma, thus promoting less food intake.

This stoma, which is normally narrow, may be of variable size with adjustable gastric bands or even be reinforced with prosthetic material to prevent its expansion during other surgeries. Therefore, the small reservoir and narrow outlet produce a rapid sensation of satiety which, in patients who cooperate and are compliant, induces a change in behavior, consequently reducing caloric intake and inducing weight loss.

In this type of surgery there is a huge commitment from the patient to the doctor and the surgery, there are two rules that are essential to follow:

Chew everything very well;

Swallow food very slowly.

Because if this is not the case, the patient may experience pain, food reflux or vomiting, which may increase the size of the reservoir (dilation), the outlet or both, losing the purpose of the surgery. Consumption of liquids with a high calorie content and eating out of hours (snacks) should always be avoided. Failure to comply with these precepts is one of the most frequently seen reasons for failure. This type of surgery, simple and low risk, does not always produce the weight loss expected by surgeons and patients.

This is why malabsorption techniques began to be used, some of which include bypassing large segments of the small intestine. The big disadvantage is that the risks, complications and side effects increase with the enlargement of the intestinal bypass. Together with your surgeon, you should fully evaluate the risks and benefits of each operation. However, always bear in mind that the more complex the surgical intervention to help you lose weight, the more serious the risks and side effects.

Ask your doctor, find out completely what could happen to you with any of the surgical procedures, contact other patients and only after you are sure of the surgery you are going to perform, proceed with the surgery. Always bear in mind that surgery does not cure obesity and that only well-informed patients willing to change their lives make these operations a success.

There are many sources available on the market to help you choose a surgical technique, including the Internet, but never forget to clarify properly with your doctor, as only he can inform you of all the changes you will undergo and only he can choose the best surgical method to help him lose weight.

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