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Classic Roux-En-Y Bypass

A gastric bypass procedure will alter your digestive tract by reducing your stomach size and connecting the newly created pouch to the small intestine directly.

The smaller stomach pouch will help you feel full sooner and will reduce your hunger, while the bypassing of a portion of your intestine will reduce the energy absorbed from the ingested food, as well as the absorption of other nutrients.

The Surgery

The surgery is mostly performed laparoscopically (keyhole surgery), unless required by the presence of multiple previous abdominal surgeries.

During surgery, we first fashion a small pouch out of the upper portion of the stomach.

We then cut the small bowel at around 70 cm from the stomach and connect it to the new stomach pouch.

The last step before stapling and stitching is the connection of the old stomach and the first 70 cm of your small intestine to the small intestine now attached to the new stomach pouch. We normally measure around 1.2 meters from the new stomach pouch and connect the old stomach and the intestine there.

  • After surgery, you will most likely stay 2 days at the hospital
  • If you are well and there are no issues on the first day post-surgery, you will try sipping water, and progress to a clear fluids diet if appropriate
  • If you have had a laparoscopic procedure (keyhole), you should experience little to no pain
  • If you have diabetes, we will set a plan for the interim management of your medications, which in many cases will be decreased significantly
  • Heart and blood medication should be recommenced as soon as possible, unless otherwise recommended or other changes have been encountered
  • Arthritis medication in most cases has been stopped. Post-surgery it might be needed to find alternative medications or methods of administration
  • Blood thinning medication will be discussed and arranged according to your situation
  • Cholesterol medications are not essential and can be stopped for a while
  • You will need vitamin and mineral supplements and we normally start with those in liquid form until you are able to consume normal food
  • The wound will be covered with waterproof dressing, and you should be able to shower normally
  • You should be able to walk around from the first day, and drive around your 5th or 7th day after surgery
  • We recommend sticking to gentle and slow walking in the first 2 weeks and move to brisker walking 2 – 4 weeks after surgery. You should be able to go jogging and swimming 4 weeks after surgery and resume all activities 6 weeks after surgery
  • You should be able to attend light duties at work by 1 – 2 weeks after surgery
  • Intimacy could resume around 3 – 4 weeks after surgery
  • We recommend refraining from long distance travelling at least until 5 weeks after surgery
  • You are highly recommended to stop smoking indefinitely
  • Remember that we will support you during our follow-up appointments, and that you can always call Dr Khaleal’s rooms during working hours and the private hospital after hours or during the weekend

In the weeks after surgery, you will have to slowly introduce more and more solid foods, starting from full clear liquids. You will be asked to eat very small amounts of food every hour throughout the day. Additionally, we highly recommend taking supplements to help your body absorb the nutrients from the small amount of food you consume.

Read our post-surgery diet information pack here to know more about the details of your diet after the procedure.

Possible Complications

Every surgery has its potential risks, and here are the ones most commonly related to Gastric bypasses.

Internal hernias

Changing and diverting the digestive system will lead to potential internal hernia sites. To avoid this, we stitch and close these sites, but this problem can’t be avoided completely. At SMS only 2% develop this complication.


Leaking from joints is another potential complication. Leakage after a gastric bypass is less dangerous than the one from a sleeve gastrectomy.

The most common leakage site is the connection site between the new stomach pouch and the small intestine. We usually do double layers of stitching to this site, to help prevent the incidence of leakage accidents.


Bleeding episodes can happen from the joints, or from any other abdominal structure. These episodes are similar to those any other abdominal surgeries.

  • Bleeding episodes within the first 24 – 48 hours are mostly inside the bowel’s inner layers (bowel lumen). We use fine staples and sew the joint sites carefully to avoid these episodes, and most of these episodes will settle down spontaneously. In the rare occurrence where they do not, we intervene surgically and stop the bleeding
  • Bleeding from the joint between the stomach pouch and the small intestine after 48 hours from surgery might be due to a marginal ulceration of the site. This can be quite troublesome and difficult to control. We observe a much higher rate of these episodes on smokers who did not stop before surgery as recommended.

We usually decline operating on patients who are not willing to stop smoking before surgery to avoid this complication.

Factors that might increase your chance of bleeding are:

  • Smoking. The lower blood supply caused by smoking facilitates the creation of ulcers around the new joint sites, leading to severe bleeding episodes
  • Congenital deficiency of clotting factors
  • Systemic illness like kidney impairment
  • Blood-thinning medication, whose administration is dependent on several factors, like high risk of clotting, or having a cardiac stent
  • Herbal medication could increase the risks of bleeding significantly (e.g. ginger, garlic and other herbal medicine)


Any surgery can lead to infection, either at the site of the surgery or other sites as consequence of surgery, like lung, urine, cannula sites —etc.

This risk of infection after a gastric bypass is very small and mitigated by our high operating standards.


Dehydration usually occurs in the first days following the discharge from the hospital. Depending on severity some might need to come back for intra-venous hydration.

Clotting and deep venous clotting

Clotting is the formation of gel-like clumps of blood, and it can prevent the normal blood flow. We observe clotting in two areas:

  1. In veins at the vicinity of the surgery, like the main bowel vein (portal vein). These clots are quite rare and are observed only in 0.5% of the patients. Most of the time these episodes are managed without surgical intervention, but they could lead to the need of surgical intervention to resect part of the bowel
  1. In the deep veins, like calves, lungs, or combination of both


Factors that might increase your chance of bleeding are:

  • Obesity
  • Smoking
  • Medicinal contraception
  • Previous history of clotting
  • Genetic defect of clotting factors
  • Poor mobilization after surgery

Before surgery and while at the hospital, you will most likely receive Clexane (40mg) to prevent blood clots. Before your hospital discharge, we evaluate your case and if needed, we provide you with Clexane for 12 days.

Dumping syndrome

Dumping syndrome is one of the most specific complication of this surgery. It can be avoided by following the post-surgery diet regimen thoroughly.

In this condition, the stomach “dumps” all ingested food into the first part of your small intestines faster than normal. The small intestine can’t absorb nutrients from food that has not been digested enough in the stomach, and this may cause nausea and abdominal cramps.

There are two types of dumping syndrome:

  1. Early dumping

Early dumping occurs when a large amount of food drops into the small intestine. With the partially digested food, the stomach will also drop stomach acid.

The body will react by diverting blood from other organs to the intestine to help with the digestion process, causing drops in blood pressure and less blood flow to the brain.

  1. Late dumping

Late dumping occurs when the ingested food that is being “dumped” in the intestine is rich in carbs or sugar. As it has not been digested as long as it should, the arrival of the food will cause a surge in the blood sugar levels. This will signal the pancreas to produce huge amounts of insulin, which will lower your blood sugar levels to levels below the recommended range (hypoglycemia). Symptoms are sweating, clammy skin, feeling of fainting.

Being well-informed about the symptoms and following your post-surgery dietary restrictions will prevent dumping syndrome.

Blind loop syndrome

Blind loop syndrome is caused by an overgrowth of bacteria in the intestine.

The overgrowth of bacteria might cause diarrhoea and augment the malabsorption effect of the gastric bypass. If symptoms remain, oral antibiotics might be needed.

Vitamin and mineral deficiencies

You will need to adhere to the recommendations that our bariatric physician and dietitian will make in order to avoid a too low or a too high supply of nutrients to your body.



Iron is usually absorbed slowly and will need plenty of stomach acid to help its absorption.  After bypass surgery, the stomach acid is distributed differently, and this might cause a lower absorption of iron from ingested foods.


Vitamin B12

Vitamin B12 needs a special protein produced in the stomach to be properly absorbed. Therefore the level of vitamin B12 absorption will be affected by surgery.

Vitamin B12 is very important for our nerve cell function and deficiencies can lead to numbness or anaemia.


Vitamin D and calcium

Calcium needs vitamin D and stomach acid to be absorbed in our bowel. A lack of calcium will cause weaker bones and can eventually affect the small glands behind our thyroid glands.

Vitamin D has other functions as well, influencing our immunity, skin and hair. Keeping an appropriate level of both is fundamental for good health.


Other vitamins, minerals, and trace elements are also disturbed unless proper replacement is ensured.


Protein deficiency, hair loss, nail weakness and decreased energy

  • Proper diet and vitamin supplements are very important to avoid all of these issues
  • Hair loss could follow any stress, surgery or significant drop in calories consumed. If an appropriate amount of protein is consumed and the vitamin levels are optimal, hair loss should be a temporary experience. It is not common for hair loss to be permanent

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