Mini Gastric Bypass

(Single Loop Gastric Bypass)

A gastric bypass is a surgical procedure to treat obesity that involves reducing the size of your stomach to facilitate early satiety and bypassing a section of your intestine to limit food absorption. As with the sleeve procedure, a reduction in size of the stomach restricts the amount of food intake and appetite.

Procedure Mini gastric bypass, One anastomosis gastric bypass

This procedure was traditionally carried out by a Roux-Y procedure where stomach and intestine are reconnected in two places. A single anastomosis gastric bypass is a modification that simplifies this procedure, reducing operating time and complications both early and late.

EXPECTED WEIGHT LOSS: 30-50% total body weight loss


Laparoscopic, 5 small incisions
Less than one hour

The gastric pouch is constructed similar to a sleeve gastrectomy but not as long. The small bowel is then measured 150-200cm downstream and joined to the end of the gastric pouch.




  • Laparoscopic procedure “keyhole surgery” so less invasive
  • Limits the amount of food ingested and also the calories absorbed
  • Increases intestinal production of GLP1 which stimulates insulin release and is more potent for diabetes cure
  • Ability to eat bread and meat is a little easier
  • A little more weight loss than sleeve
  • Potentially reversible


  • Vitamin and trace element deficiency
  • Intolerance to certain foods
  • Dumping syndrome
  • Requires a lifelong multivitamin
  • Bile reflux, though rare


  • High BMI >45
  • Diabetics
  • Severe reflux
  • Prior gastric banding
  • Patient preference


After gastric bypass surgery:

  • you will stay in hospital for 1 night and have an x-ray in the morning (gastrograffin meal)
  • you will have pain relieving medications to keep you comfortable
  • you will be given instructions to follow regarding wound care, diet and activity
  • you will take Somac or Nexium for 3 months and then stop if reflux free

Patients should:

  • Keep the incision area clean and dry
  • Avoid strenuous exercises and lifting heavy weights for 2 weeks
  • Sip water throughout the day to prevent dehydration
  • Follow the diet regimen given to you by the dietitian
  • Follow an exercise program to maintain weight loss


  • Lifelong follow up with a physician is required for blood tests to ensure proper health and nutrition
  • Bowel leak through the anastomosis (surgical joins)
  • Gallstones
  • Dumping syndrome – meals flood the intestine causing dizziness, nausea and diarrhoea
  • Nausea
  • Dehydration
  • Indigestion
  • Reactive hypoglycaemia
  • Nutrient deficiencies
  • Incisional hernia
  • Wound infections
  • Marginal ulcers
  • Stomal stenosis
  • Haemorrhage
  • Infection
  • Bleeding
  • Bile reflux
  • Venous thromboembolism

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