Abdominal Wall Defects: Omphalocele vs' Gastroschisis

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Abdominal Wall DefectsOmphalocele vs.
Gastroschisis

• Joanna Thomson, MS3
• Surgery Clerkship
• March 13, 2007

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Embryology Review

• The Midgut gives rise to
• Duodenum distal to the bile duct
• Jejunum
• Ileum
• Cecum
• Appendix
• Ascending colon
• Hepatic flexure of the colon
• Proximal two-thirds of transverse colon.

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Week 6Physiological Umbilical Herniation

• As a result of rapid growth and expansion of the
  liver, the abdominal cavity temporarily becomes
  too small to contain all the intestinal loops.
• The intestinal loops enter the extraembyronic
  cavity within the umbilical cord during the sixth
  week of development.
• As herniation occurs, the loop undergoes a 90
  degree counterclockwise rotation around the
  superior mesenteric artery.

Source Langmans Medical Embryology. Ninth
Edition.
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Week 10Return to Abdominal Cavity

• During 10th week of development, herniated
  intestinal loops begin to return to the abdominal
  cavity.
• Undergoes additional 180 degree counterclockwise
  rotation about the superior mesenteric artery.
• Factors responsible for this return are not
  precisely known... It is thought that regression
  of the mesonephros (kidney), reduced growth of
  the liver, and expansion of the abdominal cavity
  all play roles.

Source Langmans Medical Embryology. Ninth
Edition.
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Omphalocele

• Herniation of abdominal viscera through an
  enlarged umbilical ring.
• Failure of the bowel to return to the body cavity
  following physiological umbilical herniation.
  Defective mesodermal growth causes incomplete
  central fusion and persistent herniation of the
  midgut.
• Extruded viscera may include LIVER, small and
  large intestines, stomach, spleen, or bladder.
• Covered by amnion and peritoneum
• (May rupture before or at time of delivery)

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Source Omphalocele and Gastroschisis.
eMedicine.
7
Gastroschisis

• Herniation of intestinal loops through the
  anterior abdominal wall.
• Defect lateral to the umbilicus (rightgtleft)
• Abnormal involution of the right umbilical vein
  or vascular accident involving the
  omphalomesenteric artery causes localized
  abdominal wall weakness.
• No sac covers the extruded viscera.
• Having been bathed in the amniotic fluid and with
  compression of the mesenteric blood supply at the
  abdominal defect, the bowel wall may be inflammed
  and edematous. May appear to have a thick,
  shaggy membrane and loops may appear shortened
  and matted together.

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Source Omphalocele and Gastroschisis.
eMedicine.
9
Prenatal Diagnosis

• Elevated maternal serum alpha fetoprotein
• Ultrasound
• Omphalocele Gastroschisis

Source Fetal Diagnosis and Treatment. The
Childrens Hospital of Philadelphia.
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Epidemiology

• Prevalence
• Omphalocele 1/5,000 births
• Gastroschisis 1/10,000 births
• Increasing in frequency, especially in young
  women.
• Mortality
• Omphalocele 25
• Related directly to presence of chromosomal and
  other abnormalities
• Gastroschisis lt5

Source Langmans Medical Embryology, Ninth
Edition.
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Omphalocele Associated Anomalies

• Chromosomal abnormalities (50)
• Trisomies 13, 18, 21
• Congenital heart disease (50)
• Neural tube defects (40)
• Beckwith-Wiedemann syndrome
• LGA, hyperinsulinism, visceromegaly of kidneys,
  adrenal glands and pancreas, macroglossia,
  hepatorenal tumors, cloacal extrophy
• Pentalogy of Cantrell
• omphalocele, ectopia cordis, anterior
  diaphragmatic hernia, intracardiac defect,
  sternal cleft

Source Langmans Medical Embryology, Ninth
Edition.
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Gastroschisis Associated Anomalies

• Additional gastrointestinal problems (25)
• Including atresia, volvulus, stenosis
• Loss of bowel secondary to ischemia
• Compromised bowel function

Source Langmans Medical Embryology, Ninth
Edition.
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Initial Management

• Acute management aimed at maintaining circulation
  to bowel and preventing infection while
  stabilizing infant (temperature/fluids)
• Cover the defect with sterile dressing soaked in
  warm saline to prevent fluid loss
• Nasogastric decompression
• IV fluids with glucose
• Antibiotics

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Surgical Treatment

• Surgery performed to return the viscera to the
  abdominal cavity and close the defect.
• Primary Surgical Closure Success dependent on
  size of the defect and size of the abdominal and
  thoracic cavities.
• Staged Closure Gradual reduction of the
  contents into the abdominal cavity using an
  extra-abdominal extension of the peritoneal
  cavity (termed a silo) and using gentle pressure.
  Usually requires 1-3 weeks, after which the
  defect is then primarily closed.

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Source Omphalocele and Gastroschisis.
eMedicine.