Laparoscopic mini-gastric bypass

Dr Ilmar Kaur, Chief Surgeon at Bariatric Services in Estonia discusses mini-gastric bypass, a surgical weight loss technique associated with better weight loss, less complications and less weight regain in the long term compared to standard gastric bypass.

The mini-gastric bypass, or single anastomosis gastric bypass, is an effective and well-established procedure which combines some of the properties of a gastric sleeve and a standard gastric bypass. The upper part of the stomach is divided into a tube, similar to the top three quarters of a sleeve, and then joined to a loop of intestine.

The mini-gastric bypass can be used as a primary weight loss procedure. It can also be used in patients who have had previous gastric banding or sleeve surgery but have been unsuccessful with weight loss, or who have had band-related complications and have decided on revision surgery.

It is not ideally suited to patients with symptoms of reflux disease (severe heartburn that needs medication).

How does the mini-gastric bypass help you to lose weight?

The mini-gastric bypass procedure helps you to lose weight in different ways:

  • By reducing the feeling of hunger through altered gut to brain signalling
  • By enabling an earlier feeling of satiety and fullness when eating a meal resulting in a healthy portion size
  • By decreasing the amount of calories you absorb from your food as a result of bypassing 150 to 200cm of the upper part of the small intestine
  • Rerouting of the food stream produces changes in gut hormones that reverse one of the primary mechanisms by which obesity-induced type 2 diabetes occurs

It is an operation that provides good weight loss with great quality of life. The long-term results of the surgery – weight loss, effect on accompanying diseases, low mortality rate – are well documented and reliable.

The surgery

The mini-gastric bypass procedure is performed laparoscopically (keyhole surgery) under general anaesthesia. Five small incisions (between 5 and 12mm in length) are made for the insertion of the keyhole surgery instruments. Using these instruments, the top of the stomach is stapled to form a thin tube (30ml to 50ml in size). The thin tube becomes the new, smaller stomach and is completely separate to the rest of the stomach. This stomach is then sewn to a loop of the small intestine, bypassing the first part of the intestine called the duodenum and approximately 150–200cm of the bowel. The rest of the stomach and upper part of the small intestine remains in the body but is no longer used for food digestion.

In skilled hands, the surgery takes approximately 60 minutes to perform.

What are the long-term effects of the mini-gastric bypass?

Long-term effects of any weight loss surgery are reliant on a patient making the necessary changes to lifestyle, particularly in relation to diet and exercise.

Several studies have been carried out and published on the long term (over 5 years) effects of mini-gastric bypass surgery. Two years after the surgery, weight loss is 75-85% of excess body weight; five years after the surgery, the excess body weight loss is 70-75%.

Weight loss with mini-gastric bypass is as good, if not better, than that achieved with standard gastric bypass surgery in people with a higher BMI.

Many diseases connected to being overweight like sleep apnoea, type 2 diabetes, joint diseases, high blood pressure or polycystic ovary syndrome (PCOS) improve or disappear as a result of the surgery.


  • Mini-gastric bypass is particularly effective for patients with a higher BMI as the procedure has more predictable and durable weight loss outcomes compared with standard gastric bypass.
  • Most patients have an almost immediate reduction in their need for diabetic medication and some are able to completely stop diabetic medication altogether.
  • It does not require any on-going adjustments which are required with other procedures, such as the gastric band. Regular follow-up is, however, necessary to ensure weight loss is appropriate and food intake is nutritionally adequate.
  • It is effective for those people who tend towards high sugar or high fat foods. Dumping syndrome is directly linked to a high sugar, high fat intake. Symptoms of dumping are unpleasant and therefore discourage the intake of high calorie and sweet foods.


  • Lifelong usage of food supplements and vitamins is necessary for all patients.
  • Risk of severe malnutrition requiring reoperation in 0.5-1% of patients.
  • Risk of anaemia (low haemoglobin), caused by low iron levels.  Women of child-bearing age are most at risk.
  • Contrary to common concern, no studies have shown that mini-gastric bypass increases the likelihood of severe reflux or gastroesophageal cancer.


As with any surgical procedure, the mini-gastric bypass operation has a risk profile which is important to understand before proceeding. The following is a comprehensive list of issues which can occur. Most of these complications are very rare and 90–95% of patients have no issues. This list is extensive and is not intended to worry you, but simply inform you about the range of possible complications, regardless of how rare the issue may be.

Short term complications include (but are not limited to):

  • Bleeding - This occurs in less than 1 in 100 patients after the procedure. This may require blood transfusion or, very rarely, reoperation.
  • Infection - If an infection develops it may require treatment with antibiotics and can occasionally require reoperation.
  • Leaks at the staple line - This can at times require a repeat surgery, occasionally in the first few days after surgery. If these leaks persist they can turn into either communications with the skin or wound (fistula) or persistent infections within the abdominal cavity (abscesses). If this complication occurs, the length of stay in hospital can extend to weeks or potentially months after surgery. This can be a life-threatening problem. This occurs in less than 0.5% of cases.
  • Damage to organs - Any keyhole procedure can be complicated by unintentional injury to the organs near the area of operation. This may require a repeat operation to repair the damaged organs.
  • Blood clots - Deep vein thrombosis (clots in the veins) and pulmonary embolism (clots in the lungs).
  • Pneumonia/ chest infection - This occurs in less than 0.5% of cases.

Your surgical team will take all possible measures to reduce these risks, but if these complications occur, treatment may be necessary.

Possible long-term complications

  • Internal hernia - Risk of internal hernia is considerably lower after mini-gastric bypass (1:500) than after standard gastric bypass (2:100). Occasionally the loops of bowel in the abdomen can become entangled and get stuck. If this occurs, a reoperation is required to fix the problem.
  • Adhesions - Any procedure in the abdomen can cause adhesions (scar tissue). This can occur any time after the operation and can sometimes cause problems with the bowel getting stuck or twisted. This may require hospitalisation and may even require re-operation.
  • Gastro-esophageal reflux - If reflux occurs post-operatively some patients may require acid-suppressing medication. This operation should be avoided for those people with severe symptoms of reflux prior to surgery.
  • Dumping syndrome - Dumping syndrome is a group of signs and symptoms that usually occurs due to poor food choices. It is the result of high sugar foods passing too quickly into the small intestine. Symptoms can include cramping, nausea, dizziness, weakness and fatigue. Dietary advice to avoid dumping is provided by the clinic’s dietician.
  • Malabsorption of vitamins and minerals - Low levels of iron, B12 vitamin and other micronutrients can occur even if recommendations for supplementation are followed. For this reason, regular follow-up visits and blood tests once a year are strongly recommended.
  • Risk of malnutrition - 0.5-1% of patients require re-operation due to malnutrition.

In summary, mini-gastric bypass is suitable for almost all patients; it results in remarkable and sustainable weight loss and good control of accompanying diseases, improved quality of life and increased life expectancy.

Author profile

Bariatric Services in Tallinn, Estonia is the Baltic region’s largest bariatric surgery centre. With an expert team comprising experienced surgeons, a specialist bariatric nurse and an English-speaking programme co-ordinator, the clinic provides affordable access to modern surgical weight loss options and a range of post-bariatric plastic surgeries.

Get a quote for treatment abroad

Get a quote
  1. Complete the enquiry form
  2. Select countries of interest
  3. Providers respond
View online FREE GUIDE

Why treatment abroad could be right for you

- Costs/NHS funding
- Choosing a clinic or surgeon
- What if something goes wrong?

Additional information

Please provide the following information to get a better idea of the overall cost of your medical travel. We will factor in the typical price of travel, accommodation and travel insurance along with the cost of the treatment.

I am travelling from:
No. of travellers:

Skip this step  >    

Find providers of treatment in Estonia


Include medical travel agencies

 Yes  No

Medical tourism articles

Medical tourism news