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Jejunoileal bypass

A jejunoileal bypass is one of the first surgeries attempted for severely overweight individuals to help them lose weight

Although a jejunoileal bypass is now not the most common form of weight loss surgery it is still considered under certain circumstances.

This type of weight loss surgery is sometimes referred to as a malabsorptive surgical procedure. This is because, in effect the surgery reduces the amount of nutrients that the body can extract from food rather than restricts the physical amount that is eaten.

If patients have been unable to lose appropriate amounts of weight with conventional, conservative strategies including dieting, increasing activity levels and exercise this may pose a longer-term health risk. Specifically, diabetes, heart and lung disorders are all far more common in severely overweight individuals.

A jejunoileal bypass is an operation that is performed under general anaesthesia. The small intestine is a long tube that transfers any food passed out of the stomach to the lower abdomen for waste removal. While food is transported in this tube, the small intestine allows many of the nutrients to diffuse in to the bloodstream.

During a jejunoileal bypass operation, once the surgical team have safely entered the abdomen, the small intestine is cut near to the stomach and reattached nearer to the bottom of the intestine near to the colon. This allows far less time for any nutrients to be absorbed by the body when food passes through the intestine, thereby leading to weight loss.

What risks are associated with jejunoileal bypass surgery?

There are some general risks and complications with any type of surgery which include:

  • Anaesthetic risk
  • Wound infection
  • Blood clots (due to relative inactivity during recovery)
  • Nausea and fatigue following the operation
    • There are also some more specific risks associated with a jejunoileal bypass. Acute risks following surgery can include:

      • Deep abdominal infection sometimes leading to sepsis
      • Leakage of the stomach contents in to the abdominal cavity

      Longer term health risks are also a problem with a jejunoileal bypass. Due to the surgery bypassing areas of the gut that normally deliver certain nutrients to the body, this can lead to depletion of certain vitamins, minerals and fatty acids. Some health concerns related to this include:

      • Osteoporosis
      • Anaemia
      • Liver problems
      • Chronic diarrhoea

A jejunoileal bypass operation is a significant undertaking. Patients will be required to stay in hospital for several days after this operation to monitor their health. In general, patients will need to have a liquid diet for two weeks immediately after the operation.

If complications do not arise, a jejunoileal bypass can lead to significant weight loss. However, due to the possible nutritional deficiencies this surgery can lead to patients will be closely monitored by specialist dieticians. All patients undergoing a jejunoileal bypass should be aware that they will need to combine this surgery with long term changes to their diet to reduce the possibility of nutritional complications arising.

Specialists offering Jejunoileal bypass

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Mr Bilal Alkhaffaf

Consultant Upper GI and Bariatric Surgeon


The Alexandra Hospital

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Mr Kesava Mannur

Consultant General & Gastrointestinal Surgeon


The London Independent Hospital

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Mr Shaw Somers

Consultant General & Gastrointestinal Surgeon

BSc (Hons), MBChB, FRCS, MD

The Clementine Churchill Hospital

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Prof David Kerrigan

Consultant Bariatric Surgeon

MD with Distinction, FRCS, FRCSEd, MBChB

The Alexandra Hospital

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Dr Muhammed Javed

Consultant General Surgeon


The Alexandra Hospital

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