ABDOMINAL WALL DEFECTS

Dr. Catherine B. Canete

OMPHALOCOELE

• Anterior abdominal wall defect at the base of the umbilical cord with herniation of the umbilical contents

Incidence

• Small omphalocoele 1:5000 • Large omphalocoele 1:10000 • Male to female ratio 1:1 • Pacific Islanders have low risk for omphalocoele

Pathophysiology

• Failure of the midgut to return to abdomen by the 10 th week of gestation

Clinical Findings

• Covered clinical defect of the umbilical ring • Defect may vary from 2-10 cm • Sac is composed of amnion, Wharton’s jelly and peritoneum

• 50% have accompanying liver, spleen, testes/ovary • >50% have associated defects • Location: – Epigastric – Central – Hypogastric • Cord attachment is on the sac

GASTROSCHISIS

• Defect of the anterior abdominal wall just lateral to the umbilicus

Incidence

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

Pathophysiology

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

Lateral folds

• Form – Lateral abdominal wall – Future umbilical ring

Clinical Findings

• Defect to the right of an intact umbilical cord allowing extrusion of abdominal content • Opening  5 cm • No covering sac

• Bowels often thickened, matted and edematous • 10-15% with intestinal atresia

MANAGEMENT

• ABC • Heat Management – Sterile wrap or sterile bowel bag – Radiant warmer • Fluid Management – IV bolus 20 ml/kg LR/NS – D10¼NS 2-3 maintenance rate

• Nutrition – NPO and TPN • Gastric Distention – OG/NG tube • Infection Control – Ampicillin and Gentamicin • Associated Defects

• Conservative treatment – Reduction by squeezing the sac – Painting sac with escharotic agent • 0.25% Silver nitrate • 0.25% Merbromin (Mercurochrome)

• Surgical Management – Skin Flaps – Primary Closure – Staged Closure • Staged repair using silo pouch

Skin Flaps

Primary Closure

Staged Closure

UMBILICAL HERNIA

• Defect in linea alba, subcutaneous tissue and skin covering the protruding bowel • Frequent in premature infants

PRUNE BELLY SYNDROME

• Thin, flaccid abdominal wall • Dilation of bladder, ureter and renal collecting system • 1:30,000-50,000 • 95% are male

BLADDER EXTROPHY

• Defective enfolding of caudal folds • 3.3 in 100,000 births • Associated with prolapsed vagina or rectum, epispadias, bifid clitoris or penis

PENTALOGY OF CANTRELL

• Omphalocoele • Anterior diaphragmatic hernia • Sternal cleft • Ectopia Cordis • Intracardiac defect

BECKWITH-WIEDEMANN SYNDROME

• Macrosomia • Macroglossia • Organomegaly • Abdominal wall defects • Embryonal tumors

Incidence Delivery Covering Sac Size of Defect Cord Location Omphalocoele Gastroschisis 1:6,000-10,000 1:20,000-30,000 Vaginal or CS Present Small or large CS Absent Small Onto the sac On abdominal wall Bowel Normal Edematous, matted

Other Organs Prematurity IUGR NEC Associated Anomalies Treatment Prognosis Omphalocoele Gastroschisis Liver often out 10-20% Less common If sac is ruptured >50% Often primary 20%-70% Rare 50-60% Common 18% 10-15% Often staged 70-90%