Gastric by-pass (GBP) has been the most common operation performed in bariatric surgery in the last 25 years and its results are the standard reference for the new operations to be compared with.
In the GBP the volume of the stomach is reduced cutting its upper part and creating a small pouch which will be the “neo-stomach”. Next, the small bowel is cut approximately 120-150 cmt counting from the duodenum and the distal loop is sutured to the gastric pouch. The proximal loop biliary drainage and pancreatic secretions are then sutured allowing food to be digested properly. When this technique is performed, the patient will feel early satiety with low amount of food (restrictive component) and the food intake will have reduced absorption because the duodenum has been by-passed, altering the normal route of the aliments in the digestive tract.
Gastric “by-pass” is recommended for patients with a BMI>40 who have bad chronic alimentary habits as snacking frequently or being sweet-toothed, especially if a type 2 Diabetes Mellitus is associated to the obesity.
Patients must be on a liquid or semiliquid diet with alimentary supplements the first 4 postoperative weeks. After this initial period, they will take a balance and well-adjusted diet of low volume, 5-6 times a day and avoid eating anything out of the programmed time.
Obesity is probably the most common metabolic disorder in the western world. Nowadays, there are 1100 million people suffering from obesity or overweight in the world. Different types of non-surgical treatments like diet, medicines and physical exercise have been proved to reduce the pathologic body weight with unsuccessful long term results. Bariatric surgery is the only scientifically recognized treatment with proven efficacy for permanent weight-loss in a high rate of patients.
Obesity is defined as an excess of body weight due to the increase of adipose tissue in relation to a specific age, sex and height. The most common way to evaluate if a person is obese or not is calculating the Body Mass Index (BMI), a ratio between the weight (measured in Kilograms) and the height (measured in meters) elevated to the square. Obesity is classified according to the BMI in:
Overweight: 25-29,9 IMC
Obesity: 30-34,9 IMC
Severe Obesity: 35-39,9 IMC
Morbid Obesity: Apartir de 40 IMC
Mortality in morbid obesity patients is twelve times higher than in normal weight population. The risk of suffering diseases related to the Obesity and its complications is related to the degree of BMI, age and years of evolution. The most common ones are: – Dyslipidemia: triglycerides and total cholesterol levels are usually increased and consequently a higher risk of coronary heart disease. – Diabetes Mellitus: as long the duration and degree of obesity are higher, the risk of developing Diabetes Mellitus increases. Weight gain anticipates the onset of Diabetes and increases insulin requirements. – A higher risk of respiratory and cardiovascular diseases exists, as respiratory chronic failure, apnea obstructive syndrome, hypertension, heart attacks, heart failure, peripheral vascular disease and variceal disease. – Obesity patients have also an increased risk of developing tumors. In women, a higher incidence has been described of gallbladder and biliary tract carcinoma and gynecological tumors (breast, ovarian, endometrium and uterine cervix carcinoma). In men, rectal and prostate cancers are more frequent. – Other usual problems are arthrosis, gout, discal hernia, gastro esophageal reflux, liver steatosis and gallstones.
Options of treatment must be individualized considering the next two following factors: 1.- Circumstances which trigger or maintain obesity: sedentary lifestyle, alcoholism, menopause, emotional, social or working stress, pregnancy, drugs or medicines. 2.- Previous attempts to lose weight and the obtained results. Initially, the physician must agree with the patient goals easy to obtain and realistic, using a comprehensive and complete program of treatment with feeding plan, physical exercise, behavior therapy and medicines. The most part of weight loss will occur in the first 2 weeks and the ideal situation is losing 0.5-1 kg per week.
Indications for surgery in the context of Morbid Obesity are clearly established by the World Health Organization (WHO), and are mainly two: – BMI>40 – BMI>35, when any of the complications up mentioned related to the obesity are present (remember that hypertension, Diabetes Mellitus and Dyslipidemia are the most common). For surgeons, it’s very important that patients who are potential candidates for surgery have previously done and appropriate dietetic treatment and have changed their lifestyles (especially with practicing physical exercise), always under the control of an endocrinologist. If an unsatisfied or non-maintained with posterior regaining weight loss occurs, the patient is a good candidate for bariatric surgery.
Surgical options can be resumed in three groups:
– Restrictive: reduce the volume of the stomach. Then, weight loss is associated with a decrease in the volume of food consumed. – Malabsortive: weight loss will be due to a decrease in the amount of food absorbed. – Mixed: here, both the restrictive and malabsortive techniques are combined. Patient eats less volume and the food intake is less absorbed.
“Sleeve” or vertical gastrectomy is a pure restrictive technique in which the volume of the stomach is reduced >80% by removing its left and upper part (anatomically, large curvature and fundus). Sleeve is a permanent operation that helps the obese patient by two mechanisms: – Once the gastric fundus is resected, levels of the hormone Ghrelin (secreted in this anatomic area and responsible of the appetite) disappear in blood. – When the patient starts the oral intake, he or she will feel immediately satisfied and won’t have the need of go on eating. This facilitates the compliance of the diet proposed planning.
The gastric band (GB) is a pure restrictive technique of bariatric surgery in which an adjustable ring is passed through the upper part of the stomach. The volume of the stomach is then partially reduced and the patient will be satisfied with a very limited intake. It’s a reversible operation because a resection of the stomach is not performed. GB is actually the most frequent bariatric procedure performed all over the world. Initially, it’s a very attractive technique for obese patients because it’s easy to perform and safe, but mid and long-term effectiveness and ability to control the metabolic syndrome are clearly lower if compared with sleeve gastrectomy or by-pass.