Laparoscopic Gastric Bypass


Laparoscopic (keyhole) gastric bypass is considered the “gold standard” obesity operation by the majority of the world’s foremost bariatric (weight loss) surgeons. At LapSurgery we have been performing this procedure since 2009. It is particularly effective for patients with Type 2 diabetes.

There are several slightly different ways of performing a gastric bypass, at LapSurgery Australia we perform the most commonly used version referred to as a Roux-en-Y gastric bypass.

Whilst it is a more complex operation than the sleeve gastrectomy or the gastric band, it can be performed with keyhole surgery.

Each of the operations has its strengths and weaknesses and what follows is an account of the gastric bypass.

The following is general information about the gastric bypass but it does not and cannot take the place of detailed discussion with your surgeon. This information is not intended and must not be taken as personal medical advice.

Why Choose a Gastric Bypass Rather Than a Band or a Sleeve Operation?


At LapSurgery Australia we perform each of the three major types of weight loss surgery, the gastric band, the sleeve gastrectomy and the gastric bypass. In most cases we do not recommend the gastric banding so the choice lies between the sleeve gastrectomy and the gastric bypass. Studies comparing the two over five-year time frames show very similar degrees of weight loss. However, patients with Type II diabetes and those with gastric reflux have better results with the gastric bypass. The choice of operation will be discussed with you very thoroughly, and in the end, we present the facts and you make the decision as to which form of surgery suits you best.

Facts at a glance.

  • Gastric bypass has been performed for over 30 years and is well proven
  • Gastric bypass surgery is now usually performed with keyhole surgery
  • Complication rates are very low (more detail below)
  • Patients commonly lose 60 to 70% of their excess weight over 18 to 24 months
  • Weight loss is more rapid than with gastric banding surgery
  • Type II diabetics experience improvement in diabetes control within days of the operation
  • Many patients with Type II diabetes can be put into long-term remission
  • Associated conditions such as high blood pressure and sleep apnoea often improve quickly
  • Hospital stay is 3 to 4 days when performed with laparoscopic (keyhole) surgery
  • Patients can be back at work in as little as between two to three weeks
  • Unlike gastric banding surgery, regular adjustments are not required
  • You will be able to eat (small amounts of) most food types
  • Long-term follow-up, as in all bariatric operations, is vital

What Do We Do to Create a Gastric Bypass?

Looking at the diagram you will see that we have disconnected the major part of the stomach and closed it off altogether. A very small amount of stomach is left at the top with a capacity of 30 to 40-mL. So now no food goes into the major part of the stomach. (this is why it’s called a gastric bypass!)

We then move down to 50cm beyond the first part of the small bowel just after the duodenum and divide the bowel there. The disconnected small bowel is then brought up and joined to the small stomach remnant right at the top. The other end of the divided bowel is connected back into the main part of the small bowel about 1.5 metres from the upper stomach.

So the “Y” (of Roux-en-Y) consists of one limb connected to the small stomach through which food goes and the other limb coming from the bypassed stomach contains digestive enzymes from the stomach, the liver and the pancreas.

How Does a Gastric Bypass Work?

The gastric bypass works in four different ways:

1. Suppression of hunger
As you can see from the accompanying diagram, food coming down the oesophagus enters the very small stomach remnant. Food sits in this part of the stomach for a few minutes and stimulates the nerve endings in the top of the stomach. These nerve endings are there to tell the brain when the stomach is physically full. Of course, the stomach is nowhere near full but the brain doesn’t know that! As you will know from eating a very large meal and feeling your stomach is completely full, appetite is then turned off and this reduction of hunger is what makes it possible to eat much less food without the strong hunger that you get when you go on a strict diet.

2. Limited of portion sizes.
As the capacity of the upper part of the stomach is only 30 to 40 mls you simply can’t get a lot down! But don’t worry; you will get down quite enough to survive. Food passes reasonably quickly into the small bowel so as long as you eat slowly, enjoy your food and don’t rush it you should have no problems.

3. Some of the Food You Eat Will Not Be Absorbed by Your Body
Again, looking at the diagram, you will see that after food exits the small upper stomach it travels along the small bowel for about 1 ½ metres before it joins the other part of the small bowel. So in the one and a half metres of this limb there is food but fewer digestive enzymes. Food can’t be absorbed without digestive enzymes. So it’s not until around 2 metres along the small bowel until there is both food and digestive enzymes so that absorption can take place. That means that 2 metres or so of your small bowel no longer absorbs food.

4. Increase in Natural Compounds Which Can Dramatically Improve Type II Diabetes
Two of the major changes to the bowel with a gastric bypass are that, firstly, food no longer passes through the duodenum and, secondly, some partially absorbed foods enter the last part of the small bowel. Because of this, two substances known as incretins are produced in increased amounts by the small bowel.

These incretins have a profound positive effect on glucose absorption which, in combination with the weight loss, can either greatly improve diabetes control or in many cases put the diabetes into remission.

What Are the Risks?

All operations carry risks which must be weighed against the risks of the underlying problems with your weight and associated diseases. Risk will vary from person to person and must be thoroughly discussed with your surgeon before deciding to go ahead with the surgery.

Reducing the Risks of Surgery

It is better to avoid a complication than to treat it!

Continuing to smoke after having a gastric bypass can result in life threatening complications such as bleeding or perforation of the stomach.

People with significant weight problems have a higher risk of complications during any surgery. At LapSurgery, long before your operation takes place, you will undergo a comprehensive assessment of your health so that we can identify any risks and minimise these.

If, after your initial visit to the surgeon, you decide to go ahead with surgery we will arrange a comprehensive set of blood tests and an appointment with a specialist physician experienced in preparing patients for surgery and minimising any risks. Patients with significant weight problems will often have other conditions related to their weight (comorbidities) which in many cases can increase the risks of surgery. Poorly treated high blood pressure, poorly controlled diabetes, untreated sleep apnoea, vitamin D deficiency, urine infections and cardiac problems are often present and these must be treated properly before surgery. Sometimes this will involve other tests such as sleep tests, blood pressure monitoring and heart tests before we can go ahead with the surgery. The very high safety levels with which we perform this sort of surgery are very dependent on this initial thorough investigation, and optimisation of treatment, of comorbidities BEFORE surgery takes place.

One of the risks of this sort of surgery, often not listed in the usual complications, is the lack of education and understanding of both the pre-operative preparation and the post-operative management of your lifestyle and dietary habits. We have a full time dietitian at LapSurgery to educate and supervise your weight loss journey. We are also very aware that years of frustration with your weight problems and some of the prejudice you will have faced about your weight can have an effect on your mental well-being and so all patients are seen initially by our counsellor as part of the assessment. Follow up counselling is available should you wish.

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.

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

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.

Blood Clots to the Legs or Lung
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 be placed on your legs which keeps pumping blood through them to minimise the chance of a clot forming while you are on the operating table.

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

Complications Specific to the Gastric Bypass

Complications in the First Couple of Weeks.

The major risk in the first two weeks is that the join of the small bowel to the stomach does not heal properly and gastric fluid can leak into the abdominal cavity causing peritonitis. This occurs in less than one in 100 operations in people who have not had previous gastric surgery. However, in people who have had a gastric band or a gastric stapling operation in the past the chance of a leak is higher and must be fully discussed with your surgeon before going ahead.

Should a leak occur, this is a very major complication which may well involve further surgery. This could include a major abdominal incision rather than keyhole surgery.

Hospital stay in this event could stretch into some weeks and involve a stay in the intensive care unit. Exactly how we deal with this complication can vary from person to person but one way or another the leak will seal and you should make a full recovery and still achieve very good results.

Complications Occurring Weeks, Months or Years after the Operation
Narrowing of the join between the small bowel and the stomach

Occasionally, the join between the upper part of the stomach and the small bowel can narrow down and cause difficulty swallowing. This is easily fixed with a gastroscopy and dilatation performed under sedation with only a couple of hours in the hospital. This usually only occurs in the first few weeks after the operation, not later on.

Dumping syndrome

Dumping syndrome is a possible side-effect of the gastric bypass surgery particularly in the first two or three months after the operation. Dumping syndrome is usually caused by eating a high fat or high sugar food. After eating, you may feel more mild symptoms like cold sweats or nausea or you may have a more severe reaction causing dizziness, diarrhoea or vomiting. The symptoms usually last a short time but you may experience symptoms of low blood sugar levels 1-3 hours after eating and you may need to eat a high carbohydrate food. If this is happening more than occasionally, keeping a food record and a visit to our dietitian should get things back to normal very quickly.

Internal Hernias

When we rearrange parts of the small bowel for the gastric bypass there are two places where we create a “hole” through which part of the small bowel can get stuck. This can cause intermittent severe abdominal pain or even a complete blockage of the bowel. It is not always easy to diagnose and should always be considered if you have an episode of severe abdominal pain even some years after the operation. We are now very conscious of this possibility and part of every operation involves closing the two holes where the small bowel can get stuck. Even so there remains a small possibility that this could happen in the future. Surgery would probably be required and may not be able to be done with keyhole surgery. The chance of this happening is less than 5% for the rest of your life.

An Ulcer at the Join of the Small Bowel and the Upper Gastric Pouch (Anastomotic Ulcer)

This is an uncommon condition and usually can be fixed with acid reducing tablets and some variation to diet.

Weight gain

Unfortunately, a small number of patients will either not lose the expected amount of weight or will, at a later date, put some of the weight back on. It is vital that you understand that the bypass is a tool to help keep your weight down. It is not a procedure which can protect you forever from putting some of the weight back on. You must realise that you have a genetic predisposition to putting on weight and that long-term attention to the principles we will have taught you are essential to keep the weight off. Long-term follow-up, which we provide at LapSurgery, is absolutely essential to your long-term success. If there is any tendency to put weight back on you must see us immediately so that we can help you to reverse any weight gain. Unfortunately, some people feel they have failed if they start to put any weight back on and feel too embarrassed to come back and see us. The more weight you put on before seeking help, the more difficult it will be to get the weight off. We will never make you feel embarrassed about any weight gain; we are here to help you.

Vitamin deficiency

Following weight loss surgery each patient has the potential of vitamin deficiency and so LapSurgery Australia recommend to all patients that they have a regular daily multivitamin in order to reduce the risks of other medical conditions such as osteoporosis, thiamine deficiency along with many other conditions. More information is given to patients at the time of consultation.


What you have read above is a summary of Roux-en-Y 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.

We look forward to helping you.

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 1 x pre-operative and 3 x post-operative appointments
  • Surgeon, Assistant Surgeon and Anaesthetist
  • Access to on-call Surgeon at all times
  • Comprehensive after care at Medicare rebate (unless Medicar ruling changes)

Our operations are performed only in Private Hospitals. These costs can vary according to your particular private health cover. An approximate figure is around $5,800.00 out of pocket after all Medicare and Private Health cover rebates. It is possible to fund this out of pocket cost from your Superannuation, call us to enquire how. For a more accurate estimate of costs relating to your specific health fund please telephone (03) 9760 2777, email: or contact us here.

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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  • Mulgrave Private - Mulgrave
  • Knox Private - Wantirna
  • Peninsula Private - Frankston
  • Initial consult with Surgeon
  • Pre-operative assessment by Specialist Physician
  • 2-4 weeks prior you will have a consultation with the dietitian
  • 2 weeks prior you will have a consultation with our counsellor
  • 1 week prior you will have a consultation with the pre-admission nurse of the hospital
  • 1 week prior you will have a final consultation with your surgeon
  • Post-operative appointment with LapSurgery Australia's Nurse (7-10 days post op)
  • Dietitian review (1-2 weeks post op)
  • Surgeon and Nurse review (5-6 weeks post op)
  • Dietitian review (3 months post op)
  • Surgeon and Nurse review (4-5 months post op)
  • Dietitian review (6 months post op)
  • Surgeon and Nurse review (8 months post op)
  • Specialist Physician review with comprehensive blood test (12 months post op)
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