Anatomy - Gastric bypass, laparoscopic

Morbid obesity with its associated comorbidities shows a worldwide increasing incidence and prevalence, particularly in the Western world. According to the WHO, 600 million people are obese (BMI > 30 kg/m2).

Obesity and metabolic-surgical interventions are, supported by high data quality, the most effective and sustainable treatment methods for morbid obesity and superior to conservative multimodal therapies.

In addition to a long-lasting weight reduction, the comorbidities associated with obesity such as type 2 diabetes mellitus, arterial hypertension, lipid metabolism disorders, and sleep apnea syndrome can also be successfully treated.

The spread and acceptance of bariatric surgery has increased significantly worldwide in the last 20 years (2003 approx. 150,000; 2013 470,000 procedures).

The success of a bariatric procedure is assessed based on successful weight reduction and positive influence on the associated morbidities.

The Roux-en-Y gastric bypass (RYGB) is the gold standard of bariatric procedures and accounts for approx. 45%.

The consequences of the surgical measures go far beyond weight loss through a variety of complex changes in the entero-humoral axis with metabolic effects.  

The new terminology of “metabolic surgery” names the expanded indication. It is expected that bariatric surgery will gain increasing importance in the management of metabolic syndrome.

Many patients with type II diabetes mellitus show complete remission of the disease just a few days after the operation, long before significant weight loss has occurred. It is now being discussed to use “metabolic surgery” also in diabetics who are normal and slightly overweight.

The procedures initially assessed as high-risk surgery can now be performed with a manageable complication risk through the introduction of laparoscopic surgical techniques.

Bariatric-metabolic operations are not included in the standard catalog of services of German health insurance companies. Therefore, an individual application procedure must be initiated for each patient for the performance of such an operation. 

Restriction and malabsorption are indeed prerequisites for successful therapy, but hormonal and neuronal mechanisms seem to be decisive for the improved diabetic metabolic situation.

The complex interplay of hunger and satiety as well as of metabolism and energy balance undergoes a specific change through the operation.

In addition to restriction and malabsorption, due to the modified gastrointestinal anatomy after gastric bypass, there are diverse physiological changes, such as for example in gastrointestinal hormone secretion, neuroendocrine signal transmission, and the intestinal microbiome.

Patients after bypass procedures achieve, compared to purely restrictive procedures (gastric band), beyond an early feeling of satiety, a reduced feeling of hunger. All procedures that eliminate the gastric fundus as the main site of ghrelin production sustainably produce a significantly reduced feeling of hunger.

Additionally, due to the exclusion of duodenal receptors and proximal intestinal parts from the food passage as well as rapid influx of food into distal intestinal sections, there is a stimulation of enteroendocrine secretion with an improved glucose metabolism.

Postoperatively, more than 80% of patients can discontinue their insulin therapy or oral medication.

In the laparoscopic creation of a Roux-en-Y gastric bypass, a small gastric pouch (20-30 ml) is first formed. In this process, the subcardial area of the stomach is separated from the remnant stomach using staplers. There must be no connection to the remnant stomach anymore.

Then, the formed gastric pouch is anastomosed with a jejunal loop bypassed according to Roux-Y. The duodenum and a part of the jejunum are excluded from the food passage. The pulled-up loop is referred to as “alimentary limb” and is anastomosed 150 cm aboral to the gastroenterostomy with the “biliopancreatic limb” (jejunojejunostomy). After the union of these two limbs, the actual absorption of food occurs in the “common channel”.