When it comes to "biliopancreatic shunting", it means that the digestive secretions of the gall bladder (bile) and pancreas (pancreatic juice) are mixed with the food mass only in the lower part of the small intestine. This makes it difficult to break down nutrients, and the amount of nutrients absorbed from the small intestine into the bloodstream is much lower.
Biliopancreatic shunting in most obese patients results in a significant reduction in body weight. Biliopancreatic shunting is considered to be an established technique all over the world, but it is not used in Germany.
What Happens Following Biliopancreatic Shunting?
The mechanism of action is first of all based on malabsorption, which is deliberately provoked by the operation. Malabsorption means poor absorption of nutrients from the intestines. Typically, the nutrient mass from the stomach gets mixed with digestive enzymes from the pancreas and gallbladder already in the duodenum. The nutrients are broken down with their help and can already be absorbed by the intestinal mucous membrane and then transported to the blood.
However, the use of biliopancreatic shunting makes it possible to transport them much lower into the small intestine. Only there does the nutrient mass mix with the digestive juices. In this way, there is considerably less intestinal space and much less time for the breakdown and absorption of nutrients, so that most of the nutrients enter the large intestine undigested and come out with faeces.
However, weight loss is achieved not only through malabsorption. The second principle of action is the so-called restriction. Biliopancreatic shunting, among other things, considerably reduces the stomach. Due to the reduction in stomach capacity (restriction) saturation occurs much faster and the patient eats less.
Biliopancreatic Shunting Surgical Techniques
In general, there are two versions of the operation, a self-contained biliopancreatic shunting (BPSH) and biliopancreatic diversion with duodenal switch (BPD-DS). In the case of BPSH, the stomach is reduced to a volume of approximately 250-500 milliliters. In the case of BPD-DS, in contrast to the so-called sleeve gastroplasty, the volume is reduced to only 100-200 milliliters. Thus, the restriction in the case of BPD-DS is more pronounced than in the case of exclusively BPSH. Another advantage is that the gatekeeper to the stomach (the pylorus) is preserved in the case of BPD-DS. As a result, the food mass is not easily transferred from the stomach to the intestine, and due to the pylorus it passes into the intestine more slowly and gradually. The so-called dumping syndrome is considerably reduced (see below).
Preparation for Biliopancreatic Shunting
It is important to perform a gastroscopy before surgery to rule out serious stomach and duodenal diseases. It is also necessary to carry out an ultrasound of the abdominal cavity in order to detect possible biliary dyskinesia in advance, for example, caused by bile stones. If gallstones are detected, the gallbladder is in most cases preventively removed during biliopancreatic shunting surgery, as other gallstones can quickly form later in the course of the intended weight loss. These stones very often lead to inflammation of the gallbladder and biliary tract. In addition, an electrocardiogram (ECG) is required in most cases before surgery, as well as pulmonary function tests.
How the Operation Proceeds
Biliopancreatic shunting is currently performed mainly in a minimally invasive way. This technique, also known as the keyhole technique, does not require large abdominal incisions. Instead, surgical instruments and a small special camera are introduced into the abdomen through small incisions in the skin. Minimally invasive techniques generally involve lower surgical risks than open surgeries and are therefore particularly suitable for patients with obesity who already have significantly higher surgical risks.
Biliopancreatic shunting takes place in several stages. Under general anesthesia, the surgeon introduces instruments and a camera with a light source into the abdominal cavity through incisions in the skin. Furthermore, carbon dioxide gas is pumped into the abdomen during surgery, so that the abdominal wall is lifted slightly above the organs and there is more space in the abdomen.
After that, they separate the stomach almost below the esophagus. This leaves only a small stomach at the end of the esophagus, and the rest of the stomach is removed. In the case of biliopancreatic diversion with duodenal switch, the so-called gastric sleeve of an even smaller capacity is formed instead of the small stomach.
The next step is for the surgeon to isolate the small intestine approximately 2.5 meters from the beginning of the large intestine. The lower part is pulled up and sutured directly to the small stomach or gastric sleeve. The upper part of the small intestine is no longer connected to the stomach and later serves only to transport the digestive secretions of the gallbladder and pancreas. This part is brought and sutured to the small intestine about 50 centimeters above the large intestine.
Thus, the entire part of the small intestine where the nutrient mass is mixed with the digestive juices is only half a meter long instead of a few meters. Since there is no longer enough length for complete breakdown and absorption of the food components, the nutrient mass enters the large intestine mainly undigested, where the nutrients are not absorbed at all, because the large intestine is primarily used to compress the digested food mass.
Surgery Duration, Hospital Stay and Ability to Work
Biliopancreatic shunting lasts approximately from two to three hours and is always performed under general anesthesia. The operation usually requires a hospital stay of approximately eight days, one to prepare for the operation and seven to be supervised by a doctor after the intervention. On average, about three weeks after surgery, it is possible to resume occupational activities if there are no complications.
Who Biliopancreatic Shunting is Suitable for
Biliopancreatic shunting is a procedure for people with obesity and a body mass index (BMI) of ≥ 40 kg/m² (grade 3 overweight). If metabolic diseases such as diabetes mellitus, hypertension or obstructive sleep apnoea are already a problem because of obesity, biliopancreatic shunting should be performed with a BMI of 35 kg/m².
The prerequisite for biliopancreatic shunting, as well as for all other bariatric surgeries, is that all non-surgical measures have not been successful for 6-12 months. These include, among other things, professional nutrition counseling, physical exercise and behavioral psychotherapy (the so-called multimodal concept of obesity treatment). Biliopancreatic shunting is permitted between the ages of 18 and 65, although in some cases the intervention may be performed on older or younger people.
In people with severe obesity (BMI > 50 kg/m²), surgery is sometimes divided into two parts. At first, only sleeve gastroplasty is performed. This should result in a decrease in weight as well as a reduction in the surgical risks for the second intervention (biliopancreatic shunting itself).
The malabsorption method, e.g. the biliopancreatic shunting, is especially recommended for people who cannot change their eating habits. While with other techniques (e.g. sleeve gastroplasty or gastric banding) these people are less likely to lose weight, in the case of biliopancreatic shunting, even if improper eating habits persist, weight loss is expected due to malabsorption.
Who Biliopancreatic Shunting is not Suitable for
There are a variety of physical and mental health conditions in which bariatric surgery, for instance, biliopancreatic shunting, is contraindicated. First of all, previous surgeries and gastric and intestinal defects can be serious reasons why biliopancreatic shunting is not recommended. Concomitant mental illnesses, such as addictive disorders or incurable eating disorders (e.g. compulsive overeating or bulimia) are also reasons for not using the intervention. Whether biliopancreatic shunting is possible or not is determined in advance during the consultation with a surgeon.
Effectiveness of Biliopancreatic Shunting
Biliopancreatic shunting is a surgical technique that generally helps to achieve maximum weight loss. Studies have shown that one year after the surgery, the loss of excess weight is 52% in the case of biliopancreatic shunting (BPSH) and 72% in the case of BPD-DS. The decrease in weight after the intervention, along with the purely cosmetic and body-relieving effect, has a positive effect on the patient's metabolism.
Thus, in many cases, the intervention influences the course of diabetes mellitus very positively or even cures it completely. In this way, blood glucose levels often return to normal within a short period of time after surgery, even though weight loss was low at that point. The reasons for this are still not clear. Some researchers believe that because of the changes in the gastrointestinal tract there are various hormonal changes that improve energy metabolism.
Advantages of Biliopancreatic Shunting over Other Techniques
Since the effect of biliopancreatic shunting is based on two different principles (restriction and malabsorption, see above), this technique is particularly effective for people who are overweight because of excessive consumption of high-calorie foods or drinks. For such people, sometimes referred to as people with a sweet tooth, techniques that only make the stomach smaller, such as ballooning, gastric banding or sleeve gastroplasty, would not be effective enough.
Biliopancreatic Shunting: Risks and Complications
Biliopancreatic shunting involves various general and specific surgical risks. These include:
- General risks caused by the use of anaesthesia
- Deep vein thrombosis of the legs with a risk of pulmonary embolism
- Infection in external and internal sutures
- Leaky sutures in the small stomach/ gastric sleeve or small intestine (failure of sutures) with a risk of peritoneal inflammation (peritonitis)
The mortality rate after biliopancreatic shunting, according to studies, ranges from 0.5 to 7.6%. However, these are purely statistical figures. Individual surgical risks depend to a large extent on the physical state of health at the time of surgery.