The sleeve gastrectomy is a form of stomach reduction used for obesity treatment. During the operation, a large part of the stomach is removed, so that only a tube-like remaining stomach is retained. This way the patient feels satiety much faster with small amount of food.
The gastric sleeve surgery or sleeve gastrectomy is a stomach reduction surgery used to treat obesity (adiposity). The method is based on the food restriction principle: the intervention reduces the stomach volume to the size of a small banana. As a result, the stomach is filled even with just small amounts of food. The food stretches the stomach wall, which in turn triggers the feeling of satiety.
In addition, sleeve gastrectomy appears to prompt certain hormonal processes, which restrain the appetite. There are evidences that after a sleeve gastrectomy the stomach produces lower amounts of the so-called hunger hormone "ghrelin" and thereby additionally reduces the appetite. At the same time, hunger suppressing hormones are released. These are, for example, "GLP-1" and "peptide YY".
The hormones also have favorable effect on various metabolic processes. This is why stomach reducing surgeries are more and more often called metabolic surgeries. For example, many patients have experienced clear improvement of their existing diabetes (diabetes mellitus type 2) after the surgery.
The sleeve gastrectomy is carried out more and more often worldwide. In Germany, the sleeve gastrectomy is the most frequently performed obesity surgery.
Prior to the actual operation, it is necessary to perform certain preliminary examination. This includes an endoscopy of esophagus, stomach and duodenum (esophagogastroduodenoscopy) which is used to rule out any pathological changes such as inflammation, ulcers or tumors. A upper abdominal sonography can also be used to assess the condition of liver, gallbladder and pancreas. An ECG is also recorded and, if necessary, a pulmonary function testing (PFT) is carried out to prepare the patient for anesthesia.
A so-called protein-rich liquid phase is recommended for patients with very pronounced obesity (BMI above 40 kg/m2) and fatty liver before the sleeve gastrectomy. Depending on the hospital, it lasts for about 10 to 14 days prior to the surgery. During this time, patients should eat only liquid, protein-rich food. The goal of the liquid phase is a slight weight loss and reduction of liver fat. Detailed information about the preoperative liquid phase can be obtained directly from the treating hospital.
In sleeve gastrectomy the most of the stomach is removed. Only a two to three centimeters narrow hose (sleeve stomach) with a volume of about 80 to 120 milliliters remains.
The sleeve gastrectomy is always performed under general anesthesia. However, usually there is no need for a large abdominal incision, the intervention is performed as a so-called minimally invasive operation (keyhole technique) over small cuts in the abdominal wall. The actual surgery takes a little more than an hour and is performed using following steps:
- After the surgical instruments and the camera are introduced into the abdominal cavity it is filled with a gas (mostly carbon dioxide) to achieve better accessibility and visibility of the abdominal organs.
- Now the surgeon drags a special surgical stapler along the curved bottom of the stomach (greater curvature). The stapler performs two functions: firstly, it separated the lower part of the stomach. At the same time, it places clamps along the cut, connecting the wound edges and closing the remaining gastric sleeve. Therefore a time-consuming suturing by hand is not necessary.
- The separated stomach part is pulled out of the abdominal cavity through one of the working channels using a so-called plastic specimen pouch. Then a coloring agent is introduced into the stomach via a gastric tube. It is used to check the tightness of the clamp seam along the cut edge. If the agent does not leak, the operation can be finished.
A sleeve gastrectomy is recommended as an effective weight reduction method in very obese people with a body mass index (BMI) of 40 kg/m². In case of comorbidities such as diabetes that can be improved by a weight loss, a sleeve gastrectomy can be performed in patients with a BMI of 35 kg/m².
The precondition is that the patient has already unsuccessfully tried to lose weight under medical supervision before (with a change of diet and lifestyle). Patients should be at least 18 and at most 65 years old.
In the case of extremely obese people, the gastric surgery is sometimes performed as the first step for a more complex obesity surgery. If the patient has lost weight and thus has reduced their surgical risk, the second step is to perform a more effective operation, such as biliopancreatic diversion or gastric bypass. These operations not only reduce the food supply (restriction), but also hinder the food metabolism (malabsorption).
Sleeve gastrectomy cannot be performed in people whose overweight results from the consumption of soft, calorie-rich foods or liquids, for example, sweets, sweet drinks ("sweet-eater") or alcohol. Because these calorie carriers pass through the gastric sleeve unhampered (run through) without filling it and triggering a sensation of satiety In these cases, a malabsorptive procedure such as a gastric bypass is recommended. A sleeve gastrectomy is also not indicated in people with reflux. Acid reflux and heartburn can become more intense after the operation.
The chances of a successful weight loss after a sleeve gastrectomy are very high: First studies show that patients were able to reduce their average excessive weight by 33 to 83 per cent. Since the sleeve gastrectomy is a relatively new surgical technique, there are still no long-term results on the success of the method.
Some people experience a renewed weight gain after a few years of successful weight loss. More reliable long-term expectations offers a technique very similar to the sleeve gastrectomy called "magenstrasse and mill operation". A gastric tube is also formed in this method, similar to sleeve gastrectomy, but the remaining stomach pouch is left in the body. A study showed that this technique equivalent to the sleeve gastrectomy helps to achieve 60 percent excessive weight loss (EWL) in five years.
In contrast to other surgical procedures, the sleeve gastrectomy does not disturb the normal functioning of the stomach. The esophageal and pyloric sphincters of the stomach are also preserved. Therefore, after a postoperative transition to normal diet, patients can eat their usual food but in smaller quantities.
The procedure is shorter and more gentle compared with, for example, gastric bypass surgery. Sleeve gastrectomy is also much more effective than, for example, gastric banding.
After the operation, patients should have vitamin B12 administered via injections (intramuscularly or as short infusion) for the rest of their life. Because the intestine can no longer absorb vitamin B12 in sufficient quantities. Since a large part of the stomach is removed it no longer produces sufficient amount of "intrinsic factor" – a protein that is necessary for the absorption of vitamin B12 in the intestine.
Sleeve gastrectomy is an irreversible operation even if the patient has successfully reduced their weight.
As with any surgery, sleeve gastrectomy may also cause problems or complications. In addition to the typical risks of general anesthesia, these include:
- Injury of blood vessels accompanied by bleeding or secondary bleeding
- Injury of other organs
- Wound healing disorders or wound infections
- A hole in the gastric seam (seam insufficiency) causing the gastric contents to leak into the abdominal cavity with the risk of peritoneal inflammation (peritonitis)
- (Temporal) disorders of gastrointestinal activity
- Adhesions of the abdominal organs
Compared with other obesity surgery interventions, the sleeve gastrectomy has a lower complication rate. The individual risk depends largely on the patient's state of health.
One or two weeks after a sleeve gastrectomy the patient is supposed to eat only strained or liquid food. The hospital then recommends a nutrition plan for gradual transition to a normal diet. The goal is to divide the daily amount of food into five-seven smaller meals.
Basically, a few weeks after the sleeve gastrectomy the patient is allowed to eat any food, provided it is well tolerated. However, in order to achieve effective weight loss, the patient must fundamentally and permanently change their diet and lifestyle habits. The sleeve gastrectomy is only one – albeit very effective – component of obesity therapy.