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Summary:

  • Experienced, senior team providing a multidisciplinary approach to surgery.
  • $8,000-9,000 for patients with Private Health Insurance covering weight loss surgery

One Anastomosis Gastric Bypass Surgery

The One Anastomosis Gastric Bypass (OAGB), also known as the Mini Gastric Bypass, is a modern, effective weight loss surgery that combines restriction and malabsorption to help you lose weight and keep it off long-term.

During the procedure, a small pouch is created from the stomach and connected directly to the small intestine — reducing both the amount of food you can eat and the calories your body absorbs. The surgery typically takes about 60–90 minutesand is performed under general anaesthesia, often via keyhole (laparoscopic) technique for faster recovery.

By changing the digestive pathway, this procedure can help reduce hunger, promote early satiety, and even improve or resolve obesity-related conditions such as type 2 diabetes, high blood pressure, and sleep apnoea.

Most patients return home within 2-3 days and begin seeing results within weeks. It’s a powerful option for those looking for a permanent solution to obesity, especially if previous attempts at weight loss haven’t been successful.

  • One Anastomosis Gastric Bypass facts at a glance

    • Most commonly performed type of bypass surgery in some Australian bariatric centres
    • Typically results in 65–80% excess weight loss within 12–18 months
    • Can improve or resolve conditions like type 2 diabetes, hypertension, and sleep apnoea
    • Performed laparoscopically (keyhole surgery) in the majority of cases
    • Average hospital stay: 2-3 days
    • Return to normal activity: This can be variable but some take 3 weeks
    • OAGB is covered by many private health insurers, with item number 31575 under the MBS (if eligible)
  • Costs

    When comparing costs, please be aware that our costs include all of the following:
    • Initial consultation with Surgeon
    • Pre-operative assessment with Specialist Physician
    • Clinical Psychologist consultation
    • Dietitian consultations inclusive of 1x pre-operative, 3x post-operative appointments
    • Exercise professional appointment
    • Surgeon and Assistant Surgeon
    • Access to on-call Surgeon at all times
    • Comprehensive after care at Medicare rebate

    Our operations are performed only in Private Hospitals. These costs can vary according to your particular private health cover. It may be possible to fund this out of pocket cost from your Superannuation.

  • Risks

    As with all major surgeries, OAGB carries potential risks. It is important to weigh the benefits of weight loss against the possible side effects and complications. Our team will work closely with you to ensure you’re informed and well-prepared at every step.

  • Possible complications

    Possible Complications After Surgery (Short-Term)

    While most patients recover smoothly, some may experience early complications, including:

    • Bleeding
    • Infection at incision sites
    • Leakage at the surgical join (anastomosis)
    • Blood clots (deep vein thrombosis or pulmonary embolism)
    • Nausea or vomiting, especially during the adjustment phase

    These are typically managed promptly with medical or surgical intervention if needed.

    Long-Term Complications (Months or Years Later)

    While rare, some complications may occur well after surgery:

    • Bile reflux – stomach bile flowing into the oesophagus, causing discomfort
    • Nutrient deficiencies – especially in iron, vitamin B12, calcium, and vitamin D
    • Dumping syndrome – a rapid shift of food into the small bowel causing nausea, diarrhoea, or dizziness
    • Ulcer formation at the site of the bypass
    • Weight regain – particularly if lifestyle changes aren’t maintained

    Lifelong follow-up, including regular blood tests and nutritional support, is essential to reduce the risk of long-term issues.

  • Is OAGB right for you?

    OAGB may be a strong option for you if you:

    • Have a BMI over 35, or over 30 with related health issues
    • Want a reversible and technically simpler procedure than traditional gastric bypass
    • Are committed to long-term lifestyle changes
    • Are seeking significant and lasting weight loss
  • Locations

    Our experienced surgeons can discuss the Gastric Bypass or other weight loss surgery with you at our Dandenong North, Berwick, Frankston, Warragul or Cranbourne locations.

    See our location addresses here.

  • Risks common to all types of surgery

    The following are the commonest of the complications but please note that this is not a comprehensive list of possible complications but does cover most events.

    The Risk of the Anaesthetic

    Anaesthetic risks are extremely low because when you come to your operation any conditions which might increase your anaesthetic risk such as high blood pressure, diabetes or sleep apnoea will have been brought under control. All of our anaesthetists are experienced with dealing with the specific problems of patients with excess weight and have full access to all of the tests and information gathered during your preoperative assessment.

    Bleeding

    Although uncommon, bleeding can occur during an otherwise routine operation and could require blood transfusion and possibly abandoning the laparoscopic (keyhole) approach for a major incision in the abdomen. Occasionally, after a routine operation, bleeding can commence some hours after an operation and require a return to the operating theatre.

    Infections

    Again these are uncommon with laparoscopic surgery, but occasionally one of the small keyhole wounds can become infected and require antibiotics or drainage. Uncommonly, an infection inside the abdominal cavity or the chest can occur.

    Damage to Other Organs

    Although uncommon, during laparoscopic surgery it is possible to inadvertently damage another organ such as the spleen or the bowel. Normally this can be diagnosed and repaired during the operation but very rarely this damage may not be obvious until some hours or even days after the procedure and will then require appropriate management.

    Conversion to Open Operation

    Rarely, it is not possible to complete an operation with keyhole surgery and a full abdominal incision may be necessary. This is more likely to be the case if you have had previous surgery on your stomach such as a gastric band or stomach stapling.

    Blood Clots to the Legs or Lung (Pulmonary Embolus)

    Blood clots to the legs or the lungs are a very serious complication. At LapSurgery we use the maximum protection against this occurring. Shortly before the operation you will be given a blood thinning injection and have stockings placed on your legs. A further device will also be placed on your legs which keeps pumping blood through your legs whilst you’re asleep to minimise the chance of a clot forming whilst you are on the operating table.

    Using these precautions and the early mobilisation after the surgery that is possible with the keyhole operation, these complications have been uncommon in our patients.

  • Conclusion

    What you have read above is a summary of One Anastomosis Gastric Bypass Surgery. This is not sufficient information in itself and every aspect of the bypass, including the preparation for surgery and the possible complications, is always specific to an individual and must be discussed at length with your surgeon.

Video Hub

We’ve created a series of videos to explain details about the weight loss surgery process.

The team at LAPSurgery Australia are recognised for their exceptional and major contribution to the Government sponsored Bariatric Safety Registry (BSR). The BSR tracks surgical complications and provides an unbiased safety record for weight loss surgery.

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