internal herniation

Internal
herniation with bowel ischemia after Roux-en-Y gastric bypass surgery.. The different intermesenteric internal herniation sites after Roux-en-Y gastric bypass surgery: 1 = transmesocolic hernia, 2 = jejunojejunostomy mesenteric hernia, 3 = Petersen hernia [4].
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Internal
herniation with bowel ischemia after Roux-en-Y gastric bypass surgery.. Axial CE CT of the abdomen shows the mushroom sign (red line).
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Internal
herniation with bowel ischemia after Roux-en-Y gastric bypass surgery.. Coronal CE CT of the abdomen shows a diffuse haziness of the herniated mesentery (arrows)
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Internal
herniation with bowel ischemia after Roux-en-Y gastric bypass surgery.. Axial CE CT of the abdomen shows enlarged small bowel loops with thin walls and decreased contrast enhancement (white arrows) compared to normal loops (blue arrows). Note the free paracolic fluid on both sides.
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Internal
herniation with bowel ischemia after Roux-en-Y gastric bypass surgery.. Axial CE CT of the abdomen shows enlarged small bowel loops with thin walls and decreased contrast enhancement (white arrows) compared to normal loops (blue arrows). Note the free paracolic fluid on both sides.
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Intermesenteric
internal hernia after Roux-en-Y gastric bypass. There is a ‘‘mushroom’’ appearance as the bowel loops course through a relatively narrow opening and then expand.
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Internal
hernia through the foramen of Winslow. Axial image depicting the dilated caecum (C) in the lesser sac between the stomach (S) anteriorly and the pancreas (P) posteriorly.
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Dünndarmischämie
bei innerer Hernierung: Im linken Hemiabdomen zeigen sich aufgespannte, deutlich hypodense (minder- bis nicht mehr perfundierte) Dünndarmschlingen. Vergleiche normale Schlingen im rechten Hemiabdomen. Intraperativ zeigt sich partiell schon nekrotischer Dünndarm bei Einklemmung in einer inneren Hernie.
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Internal
hernia through the foramen of Winslow. Abdominal radiograph shows a gas-containing colonic segment in the centre of the upper abdomen between the liver and the gastric air bubble.
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Intermesenteric
internal hernia after Roux-en-Y gastric bypass. Hydro-air levels
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Intermesenteric
internal hernia after Roux-en-Y gastric bypass. CT examination showed mesenterial root haziness and congestion (orange arrowhead) with clustered small bowel loops (red arrows) noted tightly contiguous to the distorted mesenterial fat in the left hypochondrium region.
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Intermesenteric
internal hernia after Roux-en-Y gastric bypass. Whirl Sign (red arrow): swirling appearance of the mesenteric vessels. Note also the anastomosis point (green arrow).
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Intermesenteric
internal hernia after Roux-en-Y gastric bypass. Aferent bowel loops (orange arrow) and eferent bowel loops (green arrow)
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Radiopaedia • CC-by-nc-sa 3.0 • de

Internal hernias (alternative plural: herniae) are protrusions of the viscera through the peritoneum or mesentery but remaining within the abdominal cavity.

Epidemiology

Internal hernias have a low incidence of <1% and represent a relatively small amount of presentations, of ~5% .

Clinical presentation

The most common presentation is an acute obstruction of small bowel loops that develops through normal or abnormal apertures.

Internal hernias not infrequently self-resolve, making imaging at the time of symptomatology vital.

Pathology

The orifice that the small bowel herniates through is usually a pre-existing anatomic structure, such as foramina, recesses, and fossae (e.g. fossa of Landzert).

Pathologic defects of the mesentery and visceral peritoneum, such as from congenital maldevelopment of the mesenteries, and surgery also create potential internal herniation orifices.

Types 

Radiographic features

In contemporary practice, virtually all patients undergo CT, which is the gold standard imaging modality for assessment of bowel obstruction and suspected internal hernias. Traditionally barium studies were performed and may still on occasion be used in niche circumstances.

CT

The appearance depends on the particular internal hernia. Common features include:

  • encapsulation of distended bowel loops within an abnormal location
  • arrangement or crowding of small bowel loops within a hernial sac
  • evidence of obstruction with segmental dilatation and stasis
  • mesenteric vessel abnormalities
    • engorgement, crowding, twisting, stretching of mesenteric vessels
Fluoroscopy

The appearances on barium studies vary depending on the type and site of the internal hernia:

  • clustering of small bowel loops
  • distended bowel proximal to the site of obstruction
  • abnormal site or displacement of normal parts of the gastrointestinal tract
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu innere Hernien:
Bauchwandhernien
 
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peritoneal
cavity
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