Paraduodenal hernia

Last revised by Joshua Yap on 20 Jan 2024

Paraduodenal hernias are internal hernias due to failure of the descending or ascending colonic mesentery to fuse with the posterior parietal peritoneum. Left paraduodenal hernia is more common and can cause closed-loop bowel obstruction and infarction.

The patient may have a history of recurrent positional post-prandial pain and can present acutely with pain and vomiting due to small bowel obstruction.

  • the more common of the two paraduodenal hernias (75%)

  • small bowel herniates through a single layer of distal colonic mesentery into a retroperitoneal fossa of Landzert (2% incidence at autopsy) that accompanies this abnormality

  • there is congenital failure of fusion of the descending colon mesentery to the parietal peritoneum in the left upper quadrant

  • the less common of the two paraduodenal hernias (25%)

  • small bowel herniates through a layer of the ascending colon mesentery into the associated retroperitoneal fossa of Waldeyer

  • there is congenital failure of fusion of the ascending colon mesentery to the parietal peritoneum in the right lower quadrant

  • associated with small bowel malrotation

These hernias usually appear as an encapsulated mass-like cluster of small bowel loops. A closed-loop obstruction may develop and strangulation may occur with engorged vessels, mesenteric edema and free fluid. This can progress to infarction.

Vacular landmarks around the neck of the internal hernia help to make a confident diagnosis:

Small bowel loops may form a cluster in normal patients. Thin patients may be especially challenging since it may be difficult to follow the course of the collapsed loops of small bowel.

Roux-en-Y loops (e.g. bariatric surgery or liver transplant) can be complicated by internal hernias.

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Cases and figures

  • Case 1a: right paraduodenal hernia
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  • Case 1b: right paraduodenal hernia
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  • Case 2b: Left paraduodenal internal hernia
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  • Case 2a: Left paraduodenal internal hernia
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  • Case 3: right paraduodenal hernia
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  • Case 4: right paraduodenal hernia
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  • Case 5: left paraduodenal hernia
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  • Case 6: left paraduodenal hernia
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  • Case 7: left paraduodenal
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  • Case 8: left paraduodenal
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  • Case 9: right paraduodenal
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  • Case 10
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  • Case 11: with closed loop obstruction
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  • Case 12: SBO due to left paraduodenal hernia
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