Risks of the Gastric Bypass

As with any surgical procedure, the gastric bypass gastrectomy has a risk profile which is important to before proceeding. The following is a comprehensive list of issues which can occur. Most of these complications are very rare and 90–95% of patients have no issues.

This list is extensive and is not intended to worry you, but simply inform you about the range of possible complications, regardless of how rare the issue may be.

Possible Short Term Complications

Acute complications include (but are not limited to):

  • Bleeding – This occurs in less than 1 in 100 patients after the procedure. This may require blood transfusion or rarely reoperation.
  • Infection – If an infection develops it may require treatment with antibiotics and can occasionally require reoperation.
  • Leak – A leak of fluid can occur through the new join between the stomach and intestines if it does not heal well. This can happen in the first few days after surgery and may require reoperation. If these leaks persist they can leak to the skin or wound (fistula) or cause a persistent fluid infection in the area (abscess). If this happens, length of hospital stay may be extended to weeks or even months after surgery, and it may be a life-threatening problem. This occurs in less than 1% of cases.
  • Ulcers – Just like ulcers can occur in a normal stomach, they can also occur in the new stomach pouch after a gastric bypass. For this reason, patients need to take anti-ulcer medication for 3 months after surgery. Sometimes ulcers can still develop and require additional therapy to manage.
  • Damage to organs – Any keyhole procedure can be complicated by unintentional injury to the organs near the area of operation. This may require a repeat operation to repair the damaged organs.
  • Blood clots – Deep Venous Thrombosis (clots in the veins) and pulmonary embolus (clots in the lungs).
    Pneumonia/ chest infection.

We take measures aimed at reducing these risks, but if complications occur, additional treatment may be necessary.

Possible Long Term Complications

  • Wound hernia – Any wound of the abdominal wall has a chance, anytime in future, of developing a hernia (some of the bowel or fat from inside the abdomen can get stuck underneath the skin). If this happens it needs to be assessed, and if it is red, hot and painful it should be seen to quickly as it may be an emergency.
  • Anastomotic stricture – It is important to keep the new connection between the stomach and the intestines small so as to achieve the right amount of weight loss. Sometimes this means the connection is too tight (less than 1 in 10 patients). If this occurs it may require stretching under endoscopy (camera into the stomach).
  • Internal hernia – Occasionally the loops of bowel in the abdomen can become entangled and get stuck. If this occurs, a reoperation is required to fix the problem. If there are any unexpected abdominal complaints it is important to be assessed quickly by the surgeon.
  • Adhesions – Any procedure in the abdomen can cause adhesions (scar tissue). This can occur any time after the operation and can sometimes cause problems with the bowel getting stuck or twisted. This may require hospitalisation and may even require re-operation.
  • Failure of weight loss/weight regain – This usually occurs when dietary advice is not followed. If you eat too much food at once this can stretch the small stomach pouch making it easier to take larger volumes at meal times in the future.
  • Dumping syndrome – Dumping syndrome is a group of signs and symptoms that usually occurs due to poor food choices. It is the result of high sugar foods passing too quickly into the small intestine. Symptoms can include cramping, nausea, dizziness, weakness and fatigue. More information about dietary advice to avoid dumping will be provided during your visit to the dietitian.

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