Mini Gastric Bypass

Mini Gastric Bypass Procedure

Our surgery makes the stomach much smaller and by using a clever loop the food you eat misses out a short segment of the upper gut. This causes very effective, long lasting and healthy weight loss.

Expected results:

You can expect to lose 30 - 35% of your total body weight during treatment. We usually see an almost immediate resolution of type 2 diabetes, and high blood pressure is often improved as well.

Who it works especially well for:

This works very well for clients with BMI over 35, as well as those with type 2 diabetes and / or high blood pressure.

Additional Information

  • Mini Gastric Bypass Procedure

    Also known as Single Anastamosis or Omega Loop gastric bypass. The procedure takes 1 – 1.5 hours under a general anaesthetic. Clients usually spend two nights in hospital although occasionally clients do go home after one day.

    Weight loss begins immediately as your metabolism is improved. If you have type 2 diabetes this may be gone after one day and you may not need your blood pressure tablets.

  • Treatment Pathway
    • Treatment Pathway Step 1Consultation
    • Treatment Pathway Step 2Operation
    • Treatment Pathway Step 3Routine follow up
  • Procedure information

    The mini gastric bypass (MGBP) works both by restricting the amount of food that can be eaten at any one time, and by causing malabsorption and also by altering gut hormones involved in appetite control.

    The main difference between the standard Roux-en-Y gastric bypass procedure (RYGBP) and the mini gastric bypass (MGBP) can be seen by comparing the two diagrams below. It is clear that in the case of the MGBP there is only one join or anastamosis, whereas in the RYGBP there are two – an upper and a lower. Because of this the MGBP can be done in less time than the RYGBP and – at least theoretically – with fewer early complications. Studies show that weight loss and health benefits resulting from mini gastric bypass are probably a little higher than with the standard Roux-en-Y gastric bypass.

    Gastric Bypass

    Mini Gastric Bypass


    In the first part of mini gastric bypass surgery the stomach is divided and a small tube of stomach created which becomes the pouch. This is the restrictive part of the procedure and means that only a very small amount of food can be taken at any one time.
    Next, the surgeon brings up a loop of bowel (about 200-300cm long) and joins this to the lower part of the stomach pouch. (The joining of bowel to bowel, or stomach to bowel is called an “anastamosis”). This means that food passes from the small pouch into the small bowel where it meets the digestive juices which have moved downwards from the main part of the stomach. In effect, therefore, about 2-3m of small bowel has been bypassed before absorption of food (and calories) can take place. Fewer calories absorbed, means weight loss.

    There is one potential problem with mini gastric bypass surgery. Because the pouch is small and is joined close to the flow of digestive juices, it is possible for these juices to “reflux” up into the stomach pouch causing inflammation and painful ulceration.
    It must be said that most of the recent studies do not seem to report this as being much of a problem in practice, but if it occurs it is relatively simple to deal with and requires revision to a standard gastric bypass.

    At present, the short answer is we do not know. Mini gastric bypass surgery is quicker because it is a single stage procedure, but in practice and in experienced hands the time difference is not great. There is some preliminary evidence to show that the early complication rate of MGBP is lower than that for RYGBP, but operative mortality is the same. Moreover short-term weight loss may be greater with the Mini bypass secondary to the malabsorption it creates. But it is also worth bearing in mind that long-term data for MGBP are not yet available.

  • Pre-op information

    A few weeks before your operation, we will ask you to attend the Pre-admission Assessment Clinic. This appointment is an opportunity to check that you are fully prepared for your admission, treatment and discharge home. You may also have routine investigations such as blood tests, ECG (recording of your heart) or a chest x-ray done at this time to check your fitness for surgery. An anaesthetist will also see you at this appointment.

  • Preparation for the operation

    Please follow the pre-operative diet sheet for bariatric surgery before your operation.

    Make sure you go for a 30 minute walk every day, as this is good cardiovascular exercise. This will help reduce the risk of post-operative complications, as well as help you lose some weight prior to surgery. If you smoke, try your best to stop six weeks before your planned surgery date.

    You should also do deep breathing exercises whilst you are having your 30 minute walk each day.

    Please do not have anything to eat (not even sweets or chewing gum) six hours before surgery, and nothing to drink two hours before surgery.

    • If you regularly take medicines in the morning, you should take them before 7.00 am, with a small sip of water if necessary.
    • If you are diabetic, you must not take your insulin or diabetic tablets on the morning of your operation.
    • If you take blood-thinning medications (such as warfarin or aspirin) and/or are allergic to any medications, please contact us well in advance before your surgery.
  • On the day of the operation

    You will be admitted to the ward on the day of your operation. Your temperature, blood pressure, respiration rate, height, weight and urine will be measured to give the nurses a baseline (normal reading) from which to work. We will measure you for special stockings (sometimes known as ‘TEDS’) to prevent blood clots (known as ‘DVT’ or ‘deep vein thrombosis’) from forming in your legs following surgery. We may also start you on anti-coagulant (blood-thinning) injections to help minimise this risk. The surgeon will explain the procedure to you in detail before asking you to sign a consent form. This is to make sure that you understand the risks and benefits of having the operation.

    All make-up, nail varnish, jewellery (except wedding rings, which can be taped into place), body piercings and dentures must be removed. One of the nurses will then come and prepare you for the operating theatre.

  • After surgery

    You will wake up in the recovery room before you are taken back to the ward.

    Please tell us if you are in pain or feel sick. We have tablets/ injections that we can give you, as and when required, so that you remain comfortable and pain free.

    You may feel light-headed or sleepy after the operation. This is due to the anaesthetic and may continue until the next morning. It is also common to have a sore throat for 2 or 3 days after having a general anaesthetic. This sometimes happens because the anaesthetist (specialist doctor) has to pass a tube down your windpipe to give you the anaesthetic gases that keep you asleep during the operation.

    Four hours after your operation we will ask you to stand up and start moving around.

    Please make sure that you do your breathing exercises 10 times every two hours (between 8.00 am and 10.00 pm) and walk around for 10 minutes every two hours. You can combine doing your breathing exercise with walking around as you did before your operation.

    Your wound may have been closed with clips that will be removed in clinic 7–10 days after surgery.

    You will be allowed to start slowly sipping unlimited amounts of water, tea, coffee, milk, squash, Ribena, soups or Bovril on the day of surgery.

  • Going home

    Provided you are well enough, you should be able to go home 1 – 2 days after your operation. We will give you a 1 week supply of medication to take home with you.

    If possible please arrange for someone to come and collect you by car on the day of your discharge home as you will not be able to drive yourself or travel on public transport.

  • At home

    You should continue to go for a minimum of a 30 minute walk every day as this is good cardiovascular exercise. It will also reduce the risk of post-operative complications. Your breathing exercises should be continued 3 times a day for the next 6 weeks.

    You may feel different sensations in your wound such as tingling, itching or numbness. This is normal and is part of the healing process.

    However, if you experience a high temperature or fever, swelling, pain, discharge or excessive redness around the wound site, please contact us.

    If you are unable to swallow or are having difficulties in swallowing please contact us using the numbers given to you before you go home.

    You will be given a diet plan to follow by the dietician prior to surgery, but in brief you will be expected to follow the basic diet structure as outlined below:

    • Days 2–6 after surgery, you will be on a liquid diet
    • Days 7–13 after surgery, you will be on a puréed diet
    • Weeks 2–4 after surgery, you will be on a soft diet
    • After 4 weeks you can return to a regular diet
  • What happens next
    1 Week after surgery

    You may still have some abdominal discomfort which can be caused by your wound or the reduced size of your stomach. You can take painkillers for this if necessary. You should be able to return to work. However, you should avoid doing any heavy lifting for the next six weeks. Make sure that you continue to walk for 30 minutes each day, as well as do your breathing exercises 3 times a day using your inspirometer. Continue following a predominantly liquid diet as instructed by your dietician. See your diet sheet for ideas and meal plans.

    2 - 4 Weeks after surgery

    You should now be able to start on a diet of puréed foods (see diet sheet for examples of meal plans). You may experience symptoms of ‘dumping syndrome’. This is where you may feel sweaty, light headed and have diarrhoea after eating refined carbohydrates such as sucrose (table sugar) or fructose (fruit sugar). You may also notice intolerance to milk based products; if this occurs, switch to non-dairy soya based alternatives.

    Make sure that you continue to walk for 30 minutes each day, as well as do your breathing exercises 3 times a day using your inspirometer.

    4 - 8 Weeks after surgery

    You can now start eating a diet of predominantly soft foods. Make sure that you continue to walk for 30 minutes each day, as well as do your breathing exercises 3 times a day using your inspirometer.

    8 Weeks after surgery

    You can start eating ‘normal’ food (solids), but be careful with any food that does not crumble in the hand, such as bread or broccoli because these can swell in the stomach causing bloating. Make sure that you continue to walk for 30 minutes each day, as well as do your breathing exercises 3 times a day using your inspirometer.

    3 Months after surgery

    You will have your third post-operative outpatient appointment to see the doctor. Blood tests will be taken at this appointment.

    1 Year after surgery

    You will have your fourth post-operative outpatient appointment to see the doctor. Blood tests will be taken at this appointment.

    After the first year

    We would like to see you on a yearly basis. Blood tests will be taken at this appointment.