1. Abdominal Wall Defects Priscilla Joe, MD Children’s Hospital and Research Center at Oakland

6. Omphalocele Membrane sac arising from the umbilical cord covers intestines Outer membrane layer consists of amnion and inner lining of peritoneum Size ranging from small->giant defects containing liver, small and large bowel, stomach, spleen, ovaries, and testes Associated with foreshortened bowel and malrotation Small abdominal cavity and pulmonary hypoplasia

8. Gastroschisis No membrane covering Abdominal wall defect typically 2-4cm diameter Lateral to the right side of the umbilical cord Usually contains midgut and stomach Thickened, atretic, and possibly ischemic bowel Associated with malrotation

9. Embryology of Gastroschisis Failure of vascularization of the abdominal wall due to abnormal involution of the right umbilical vein or a vascular accident of omphalomesenteric artery causes abdominal wall weakness and subsequent rupture Rupture of a small omphalocele with absorption of the sac and growth of a skin bridge between the abdominal wall defect and umbilical cord

10. Embryology of Omphalocele Normally, midgut returns to the abdomen by 10 th week of gestation Somatic layers of cephalic, caudal, and lateral folds join to close abdominal wall With omphalocele, folds fail to close

11. Gastroschisis and Omphalocele Combined incidence of 1 in 2000 births Male-to-female ratio is 1.5:1 Overall survival > 90%

12. Gastroschisis Increasing incidence Associated with young maternal age and low gravida Associated with prematurity and low birth weights

13. Omphalocele Incidence has remained constant Increased risk with advanced maternal age Probable genetic predisposition Associated syndromes and anomalies (45-55%): - gastrointestinal - cardiac - trisomy 13, 18, 21 - OEIS complex (omphalocele, bladder extrophy, imperforate anus, spinal defects - Beckwith-Wiedemann - pentalogy of Cantrell - cleft palate - pulmonary hypoplasia May be associated with maternal use of valproic acid

14. Beckwith-Wiedemann

15. Pentalogy of Cantrell

16. Diagnosis AFP synthesized in fetal liver and excreted by fetal kidneys and crosses placenta by 12 weeks Elevated maternal MSAFP in neural tube defects, abdominal wall defects, duodenal or esophageal atresia 40% false positive rate Fetal ultrasound after 14 weeks gestation Amniocentesis and fetal echocardiography

17. Treatment NGT to low intermittent suction Use of bowel bags, saran wrap Conservation of body heat and fluid losses Antibiotics Careful positioning to avoid kinking of mesenteric vessels 1.5 times maintenance fluids with isotonic fluids

18. Surgical Management Operative repair within 2-4 hours of birth Primary closure for smaller defects Delayed primary closure for large defects –Avoid compromised ventilation and abdominal compartment syndrome –Use of silo with sequential reduction of abdominal contents –Later fascial closure

20. Mortality/Morbidity Short gut syndrome NEC Gut dysmotility and prolonged ileus Sepsis Complications from associated anomalies/syndromes