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abdominal wall defects

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					              Congenital abdominal wall defects
 Omphalocele
 pentalogy of Cantrell - omphalocele, cardiac defect, sternal cleft, pericardial defect, central
  tendon diaphragm defect
 cloacal extrophy
 umbilical cord hernia
 gastroschisis
 ectopa cordis thoracis
                                          Omphalocele
 A large defect - greater than 4cm - covered by amniotic membrane that contains midgut and
  other abdominal organs - liver, spleen and/or gonad

                                        Gastroschisis
 Less than 4cm in diameter, has no covering membrane, contains only the midgut with the
  stomach

                                    Umbilical cord hernia
 Less than 4cm, contains only the midgut, is covered by membrane

                                      Pentalogy of Cantrell
 Supraumbilical,omphalocele containing only the liver
 through the translucent sac one can see the heart that has extruded through the diaphragmatic
  defect
 lower sternal cleft
 defect in the central tendon of diaphragm
 defect in the pericardium
 intracardiac abnormality
                                     Ectopia cordis thoracis
 Heart has no pericardium and protrudes from between the two halves of the split sternum with
  the apex pointing up toward the chin
 associated intracardiac anomalies
                                        Cloacal extrophy
 Infraumbilical omphalocele that seldom contains the liver
 extrophy of the bladder and associated epispadias
 diastasis of the pubic rami
 inperforate anus
 ileum prolapses between the two halves of the extrophied bladder

                                           Embryology
 At 3 weeks’ gestation the flat cellular disk of the embryo develops four folds that will enclose
  the body cavities
 two lateral folds form the pleuroperitoneal canals once they meet anteriorly in the midline
 the cephalic fold brings down with it the developing heart


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 the caudal fold brings with it the developing bladder

 At 5 weeks’ gestation gut tube will begin to elongate and develop within the umbilical coelom
    - a cavity in the body stalk on the anterior surface of the embryo
 at 10 weeks’ gestation the gut returns from the space within the umbilical stalk to the
    peritoneal cavity and undergoes rotation and fixation

 Omphalocele represents a failure of the body folds to complete they journey
 cephalic fold defects result in ectopia cordis or the pentalogy of cantrell
 caudal fold defects cause bladder and cloacal extrophy
 gastroschisis is caused by failure of the umbilical coelom to develop - the elongating intestine
  has no space to expand and rupture the body wall
 umbilical cord hernia - failure of the midgut to return to the peritoneal cavity at 10-12 weeks

                                        Possible teratogens
 Cigarette smoking
 vasoconstrictive agents
 birth controll pills
 aspirin
 narcotics
                                     Antenatal diagnosis - US
 Omphalocele can be distinguished from ghastroschisis by the presence of a sac and from
  umbilical cord hernia by the presence of the liver in the defect
 detects associated anomalies:
    in gastroschisis intestinal atresia
    in omphalocele cardiac anomalies


                                Amniotic fluid and serum tests
 Elevated alpha fetoprotein (AFP) in maternal serum and amniotic fluid
 elevated amniotic fluid acetylocholinesterase (AChE)
                                        Obstetric delivery
 Cesarean section to avoid injury to the bowel or tearing of the omphalocele sac
 antenatal intevention - amniotic fluid exchange

                                      Omphalocele - incidence
 1 to 2,5 per 5000 live births
 male preponderance

                               Omphalocele - associated conditions
 Cardiac
 chromosomal
 Down’s syndrome
 macrosomia
 gastroesophageal reflux


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 cryptorchidism
 musculoskeletal
 neural tube defects
Intestinal atresia
Meckel’s diverticulum
                                    Gastroschisis - incidence
 2 to 4,9 per 10.000 live births
 male preponderance

                              Gastroschisis associated conditions
 Intestinal atresia
 small for gestational age
 premature
 gastroesophageal reflux
 cryptorchidism

                                Omphalocele - operative closure
 Primary closure
 reduction of intestine contained in a preformed Silastic silo
                                  Omphalocele - initial care
 Surgery is urgently needed to increase a chance for primary closure
 nasogastric tube should be placed early to keep the intestines decompressed
 ventilator support and supplemental oxygen should be supplied as needed
 cardiology evaluation and echocardiography

                                   Gastroschisis - initial care
 Patient is frequently premature and closer attention must be paid to heat preservation,
  respiratory support
 increased fluid needs and heat loss - surface area of exposed intestine
 the faster the bowel can be reduced, the more likely primary closure can be achieved
                              Gastroschisis - operative technique
 Surgeon holds the umbilical cord up and loop by loop reduces the intestine
 it is helpful to evacuate meconium from the rectum by anal dilatation

                                  Umbilical cord hernia - operation
 This defect is easily reduced by holding the sac upward and gently massaging the bowel into
  the peritoneal cavity
                          Ectopia cordis thoracis and cephalic fold defect
 It is difficult to replace the heart in the thoracic cavity without kinking the great vessels
 wide intrathoracic dissection around the heart and great vessels has been advocated to increase
  the space within the chest
 pentalogy of Cantrell - sternal cleft and pericardial defect need no special treatment
 immediate skin closure of the omphalocele allows the patient to grow and have the
  intracardiac defect treated later



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                                      Caudal fold defect
 Initial management consist of closure of the omphalocele and creation of colostomy

                                          Complications
 Gastroschisis - prematurity
 omphalocele - associated anomalies
 gastroschisis - gastrointestinal tract anomalies
 too tight closure
 delayed recovery of bowel function
                                             Outcome
 Gastroschisis - 90% survival rate
 omphalocele - 70-95% survival rate - mortality related to the associated cardiac and
  chromosomal anomalies
 there are few survivors of any form of ectopia cordis

 long term complication - short bowel syndrome




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posted:2/25/2012
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