Internal hernia following Roux-en-Y gastric bypass

Case contributed by Dr Vikas Shah


One day of acute onset lower abdominal pain. History of surgical procedure two years earlier.

Patient Data

Age: 40
Gender: Female

This is a case of an internal mesenteric hernia but not a Petersen's type (see below). There is abnormal clustering of small bowel loops in the lower abdomen, with pinching of the mesenteric vessels and mild fat stranding around the involved loops. Some enhance poorly, raising the possibility of ischemia. This is in keeping with a mesenteric hernia, which may have been iatrogenic but this is difficult to surmise purely from the images. These are most commonly seen at the site of the jejunojejunostomy. At surgery, a hernia sac was identified and the small bowel loops, whilst being ischemic were not necrotic and no resection was necessary.

Case Discussion

One of the concerns in someone presenting with acute abdominal pain after this surgery is an internal hernia. This used to be seen more commonly than now, due to an iatrogenic defect in the transverse mesocolon where the small bowel was brought up to anastomose onto the stomach. However, the procedure has changed and is now done with an "antecolic" approach meaning that the transverse mesocolon is not breached. However, other small mesenteric defects may still be created - leading to herniation of small bowel loops behind the gastrojejunostomy. This is know as a Petersen's hernia.

This particular case is neither a transmesocolic nor a Petersen's hernia - the hernia is through a mesenteric defect presumably secondary to a defect created at surgery.

Learning points: 

  • contrast enhanced CT is the test of choice in someone presenting with abdominal pain following Roux-en-Y gastric bypass surgery.
  • keep a high index of suspicion for internal hernia formation
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Case information

rID: 37822
Published: 24th Jun 2015
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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