Abdominal wall defect

Abdominal wall defect

1. ABDOMINAL WALL DEFECTS

2. Introduction Abdominal wall defects are a type of congenital defects that allows the stomach , the intestines , or other organs to protrude through an unusual opening that forms on the abdomen . During the development of the fetus , many unexpected changes occur inside the womb .

3. Definition Abdominal wall defects are birth defects that allows the stomach or intestines to protrude

4. Types The two main abdominal wall defects are ; Omphalocele Gastroschisis

5. OMPHALOCELE Definition It is a defect in abdominal wall musculature and skin with protrusion of abdominal viscera contained within a membranous sac.

6. Incidence Small omphalocele 1:5,000 Large omphalocele 1:10,000 Male to female ratio 1:1 Pacific Islanders have low risk for omphalocele 70% associated with congenital anomalies such as Bowel atresia , Imperforated anus , Trisomes 13, 18, 21, Beckwith – Wiedman Syndrome

7. Etiology Due to failure of midgut to return to abdomen by the 10 th week of gestation during midgut rotation

8. Pathophysiology Failure of the midgut to return to abdomen by the 10 th week of gestation

9. Risk Factors Increased maternal age more than 40 years Twins High gravida Consecutive births

10. Clinical Features Covered clinical defects of the umbilical ring Defects may vary from 2-10cm Sac is composed of amnion, Wharton’s jelly & peritoneum The umbilical cord insert directly into the sac in an apical or lateral position Small one contains intestinal loops only Large one contains liver , spleen , bladder , testes/ovary

11. Diagnosis About 90% of Omphalocele & Gastroschisis diagnosed prenatally Alpha – feto – protein synthesised in fetal liver & excreted by fetal kidney & crosses placenta by 12 th weeks. Prenatal ultrasound after 14 th week gestation is the confirmatory test

12. Prenatal Ultrasound Findings are Abdominal organs herniated outside the abdominal cavity with an abnormal insertion of umbilical cord into the membrane rather than into abdominal wall The mass contents are intestinal loops , liver , spleen , gonads etc

13. Management Evaluation for associated anomalies & monitoring of fetal growth Echocardiography: high risk for CHD Prenatal monitoring of fetal growth : high risk of IUGR Other specific evaluation for associated pulmonary hypoplasia Prenatal counseling about the expected hospital course & the long term prognosis

14. After Delivery The initial evaluation & resuscitation to a babies with an omphalocele is Follow same protocol & sequence of all newborns Should be handled carefully to prevent the omphalocele membrane from tearing After initial stabilization for the newborn should be inspected to confirm that it is intact & then covered with a non adherent dressing to protect the sac

15. Primary closure Small defects (<4cm) excision of the sac and closure of the fascia and skin over the abdominal contents

16. Mesh patch Medium defects(6-8cm) Consecutive Large defects (1o-12cm)apply topical application – Beta-dine ointment or silver sulfadiazine to make intact sac till the baby is bigger & more able to tolerate major operations

17. Long Term Outcomes Small will recovery well The outcomes determine by the severity of associated anomalies , so babies with giant omphalocele have increased morality & morbidity GERD Hernias Respiratory infection Failure to thrive

18. GASTROSCHISIS Definition It is the defect in the abdominal wall was displaced to the right of the umbilicus and eviscerated bowel was not covered by a membrane

19. Incidence 1:20,000-30,000 Sex ratio 1:1 10-15% have associated anomalies 40% are premature /SGA

20. Etiology Failure of migration and fusion of the lateral folds of the embryonic disc on the 3 rd – 4 th week of gestation Disruption of the right omphalomesenteric artery as midgut returns to abdomen by 10 th week of gestation causing ischemia of the abdominal wall and weakness then herniation Rupture of omphalocele Folic acid deficiency

21. Pathophysiology Abnormal involution of right umbilical vein Rupture of a small omphalocele Failure of migration and fusion of the lateral folds of the embryonic disc on 3 rd -4 th week of gestation

22. Risk Factors Young maternal age Low gravida Prematurity Low birth –weight secondary to IUGR

23. Clinical Features Defect to the right of intact umbilical cord allowing extrution of abdominal content No covering sac Bowels often thickened, matted, and edematous Evisceration of the bowel leads to malrotation Constriction of the base may cause intestinal stenosis , atresia , and volvulus Undecended testicles

24. Diagnosis About 90% of Gastroschisis & Omphalocele diagnosed prenatally Polyhydramnios MSAFP Amniocentesis

25. Prenatal Ultrasound The diagnostic prenatal ultrasound findings of Gastroschisis are extra abdominal loops of bowel without covering sac

26. Management After Delivery The perfusion of the herniated contents should be carefully evaluated . If bowel ischemia or infarction suspected immediate surgical consultation is indicated . If the viscera are well perfused, it is important to next place a clear plastic bag over the exposed bowel as a temporary covering to minimize evaporative heat and fluid loss .

27. Pre-operative Management Heat management -sterile wrap or sterile bowel bag -radiant warmer Fluid management -IV bolus 20ml/kg LR/NS -D10 ¼ NS 2-3 maintenance rate

28. Nutrition - TPN(central venous line) Abdominal Distention - OG/NG tube - urinary catheter Infection control - Broad spectrum antibiotics Closure of the defect ABC

29. Surgical Management Skin flabs Primary closure : Use of own baby umbilical stump as biological dressing to seal gastrochisis defect without attempting a primary fascial closure Staged closure : In 1969 ,Allen and Wrenn adapted Schuster’s technique to treat gastroschisis

30. Long Term Outcomes Almost always with intestinal malformation Hernias at the site of repair Intestinal atresia Short bowel syndrome

31. Conclusion Abdominal wall defects are type of congenital defect that allows the stomach , the intestines ,or other organs to protrude through an unusual opening that forms on the abdomen .