The one anastomosis gastric bypass is also called the mini gastric bypass or single anastomosis gastric bypass and is a type of weight loss surgery where a new stomach is created and joining a loop of small bowl to the new stomach.  

The procedure involves the surgeon creating a new stomach (from your original stomach) and joining a loop of small bowel to the new stomach using state-of-the-art robotic technology to make 3 to 5 small incisions in the lower abdominal area. Food and fluid bypass the original stomach and part of the small bowel. 

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Weight loss occurs due to a restriction in oral intake, malabsorption of nutrients, and alterations to the actions of gut hormones on the bowel.

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On average, you will lose between 60-80% of your excess weight.

Anyone who has struggled with their weight and has a BMI (body mass index) of 40 or more is a suitable candidate for gastric bypass surgery.

Typically, if you are aged between 18 to 65 and are around 45 kilograms or more above a standard healthy weight, then you may be an ideal candidate.

The benefits of weight loss with gastric bypass surgery also have an instrumental effect on your overall physical and mental health.

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Diseases, such as diabetes, fatty liver, and sleep apnoea, can become more manageable or diminish completely over time. As weight decreases, so does the likelihood of getting cancers, stroke, or blood pressure problems. Some clients have reported their previous issues of gout, urinary incontinence and acid reflux have been alleviated with gastric bypass surgery.

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As you will be intaking less food, and therefore less nutrition, you may need to take a vitamin supplement for an extended period of time. It is important to visit your GP for regular check-ups to ensure you are getting sufficient vitamins and minerals.

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It’s also important to consider the mental and emotional impacts of gastric bypass surgery.

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Gastric bypass surgery is not a quick fix and should be undertaken with support from family, friends, and healthcare providers to ensure you have sufficient support before, during and after your procedure.

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Coupled with long-term healthy food and beverage choices, patients can maintain a long-lasting healthy weight and BMI.

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As with any procedure, it's always important to consider the pros and cons.

Some of the specific complications of laparoscopic one anastomosis gastric bypass include:

• Anastomotic leak (1-2%) – stomach fluid may leak out into the abdomen at the join created during this procedure, due to failure of the join to heal. This may require further surgery/procedures and a prolonged hospital stay.

• Marginal ulceration – this is an erosion/ulcer of the small bowel joined to the gastric pouch, similar to a stomach ulcer. This may cause pain in the upper abdomen or chest. Most times this can be treated with medications. Occasionally, this requires revisional surgery.

• Stomal stenosis – a narrowing at the join between stomach and small bowel. You may develop vomiting and rapid weight loss, due to inability of food and/or fluids to pass through the narrowed area. This can be treated by stretching the narrowing up with a balloon, or placement of a stent (tube), and removing it 4 weeks later. Occasionally, this requires revisional surgery.

• Stomal dilation – a widening at the join between stomach and small bowel. You may feel loss of restriction and be able to eat more. This can be fixed by narrowing the opening with stitches endoscopically (via a scope placed through the mouth). Occasionally, this may require revisional surgery.

• Internal hernia (<1%) – bowel may get trapped in a space created during the formation of the gastric bypass. This may cause a blockage of the small bowel (obstruction) or lead to a lack of blood supply to the small bowel (strangulation). This is an emergency. You must go to your local hospital immediately if you have significant abdominal pain lasting more than one hour, with or without vomiting.

• Bile reflux (<1%) – bile (fluid produced by the liver to help in digestion of fatty foods) may go up the oesophagus and cause symptoms similar to that of acid reflux/heartburn. This can be treated with medications. Occasionally, this may require revisional surgery.

• Dumping syndrome – a cluster of symptoms including nausea/vomiting, rapid heartbeat, sweating, flushing, light-headedness, abdominal cramps, and diarrhoea. This is due to eating too much or eating foods high in sugar. This can be fixed by modifying your eating habits.

• Nutritional deficiencies – even though you will need to take multivitamin supplements, you can become low in certain vitamins or minerals. Additional supplementation may be necessary. You will require lifelong follow-up and blood tests to monitor for potential deficiencies.

Your surgeon will provide you with instructions before your surgery.

To prepare for the procedure, you'll need to follow a specific diet prior to surgery. This strict diet will reduce your calorie intake as well as carbohydrates and you will primarily eat lean protein, vegetables, and low- or no-calorie fluids. In addition, you may be required to go on a meal shake replacement diet.

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There are two reasons for this:

1. To shrink your liver so your surgeon has easier access to your stomach

2. To ensure the best success of surgery

You will be expected to lose a certain amount of weight prior to your surgery.

Yes. If you don’t follow the advice of the medical team, gastric bypass surgery can fail. Gastric bypass surgery is a tool for weight loss and not a ‘magic cure’.

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Failure can mean not achieving or being able to maintain around 60-80% of the weight loss over an 18 to 24 month period.

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There are several factors for failure and one of these is the failure of patients being able to adapt to the new lifestyle. With the support of your surgeon, local healthcare providers (e.g. GP) and if necessary, a psychologist or counsellor, the possibility of failure is reduced. It's important you have sufficient support to ensure long-term success.

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If you follow your surgeon’s instructions and make healthy food choices you should have good long-term results and be able to maintain a healthy weight.