A presentation that will help clinicians attain the basic diagnostic skills required to effectively manage patients.

1. SURGERY
ABDOMINAL WALL DEFECTS
DR. CHONGO SHAPI (BSc. HB, MBChB)

2. ABDOMINAL WALL DEFETCTS
CONGENITAL UMBILICAL HERNIA
Definition
-Fascial defect at the umbilicus is frequently present in the
newborn, particularly in premature infants.
Pathology
-The defect may have invagination of the intestines or
omentum with an overlying skin covering
-Its size may actually increase with increase in intra-
abdominal pressure.
-Protrusion of bowel through the umbilical defect rarely
results in incarceration in childhood
-most dangerous defects are less than 2cm.
Etiology
-Unknown
Incidence
-Incidence thus decreases with age as the natural tendency is
to close spontaneously.
-Is very common 1;1000
-Majority .50 % are small defects less than 1cm in size-belly
button umbilical hernia in those < 2years.
Race
-The incidence is highest in blacks.
Clinical presentation
-Most asymptomatic.
-Omentum trapped in the hernia causes reflex vomiting
without intestinal obstruction.
-Classical presentation is reducing mass in the umbilical area
with or without vomiting associated with intermittent
abdominal pain.
-the hernia may become obstructed, strangulated and present
as acute abdomen.
Course
- In most children, the umbilical ring progressively
diminishes in size and eventually closes.
- -Fascial defects less than 1 cm in diameter close
spontaneously by 5 years of age in 95% of cases.
-When the fascial defect is greater than 1.5 cm in diameter, it
seldom closes spontaneously.
-Surgical repair is indicated when
1) The intestine becomes incarcerated
2) Symptomatic hernia.
3) when the fascial defect is greater than 1 cm, in
girls over 2 years
4) All children over 4 years of age.
5) Cosmesis
-In girls must be repaired because the defect may worsen in
pregnancy.
-some patients with umbilical defects develop acquired
umbilical hernia due to increase in abdominal pressure due to
ascitis
Mortality/Morbidity
-Intestinal obstruction and infection
-2-12% recurrence after the corrective operation.
-- A central venous catheter is required to monitor central
venous pressure and blood gases in anticipation of
postoperative hypovolemia from third space losses and for
TPN.
-An umbilical artery catheter can be maintained without
interfering with the repair.
-A bladder catheter can be used to monitor intra-abdominal
pressure.
OMPHALOCELE
Introduction
-Omphalocele is a congenital defect of the peri-umbilical
abdominal wall in which the coelomic cavity is covered
only by peritoneum and amnion (membrane covering).
-There are two kinds of omphalocele: fetal and embryonic.
-Fetal omphalocele is a small abdominal defect (< 4 cm
wide) with herniation of bowel into a sac of amnion that has
the umbilical vessels located at the apex of the sac. This is
due to failure in development n the periumbilical abdominal
wall after the first 8 weeks of gestation.
Other anomalies are present in less than 10% of these
patients. About 15% of congenital abdominal wall defects
are fetal omphaloceles.
-Embryonic omphalocele is due to failure of abdominal wall
closure in the embryonic stage of development (before the
eighth week).
-It is characterized by a wide abdominal wall defect, usually
greater than 4 cm in width, in which the amnion does not
protrude far beyond the abdomen, and the umbilical cord
joins the abdominal wall at the perimeter of the defect rather
than at the apex.
-Liver as well as bowel is herniated. Multiple anomalies are
present in 50% of these cases, such as
▪ Congenital heart defects (20%) (tetralogy of
Fallot; atrial septal defect)
▪ Trisomies 21, D, and E;
▪ Diaphragmatic hernia
▪ Renal anomalies.
▪ Pentalogy of Cantrell -omphalocele is is
epigastric in position and there is a defect in the
diaphragm and pericardium, allowing pericardial
herniation of bowel, a split or shortened lower
sternum, ventricular septal defect, and
diverticulum from the heart--and a small thorax
which may result in pulmonary hypoplasia
▪ Beckwith-Wiedemann syndrome, in which a
midabdominal omphalocele is associated with a
baby who is large for gestational age and who has
macroglossia, visceromegaly of the kidneys,
adrenal glands, and pancreas, hypoglycemia in
early infancy, and a high frequency of
hepatoblastoma, Wilms' tumor, or adrenocortical
carcinoma; and
▪ Hypogastric omphalocele associated with cloacal
exstrophy and spinal dysraphism.
Treatment
-Omphaloceles with small abdominal defects can be treated
by excising the omphalocele sac and reapproximating the
linea alba and skin.
- Acute management of omphalocele involves covering the
defect with a sterile dressing soaked with warm saline to
prevent fluid loss.
- A nasogastric tube should be placed on suction to minimize
intestinal distention and allow decompression
-Intravenous fluids and glucose, and antibiotics
Treatment & Prognosis
-Small defects may be closed primarily after manually
stretching the abdominal cavity.

3. - Most large embryonic omphaloceles cannot be closed
without staging the procedure which gradual reduction of
the omphalocele contents into the abdominal cavity and a
secondary closure.
-Without removing the amniotic sac, a silicone rubber sheet is
formed into a tube (silastic silo), which is sutured to the skin at
the perimeter of the omphalocele membrane.
-The silo is progressively compressed to invert the amniotic
sac and its contents into the abdomen and to bring the edges
of the linea alba together by stretching the abdominal wall
muscles.
-This requires a number of days.
- Postoperatively, third-space fluid losses may be extensive;
fluid and electrolyte therapy, therefore, must be carefully
monitored.
GASTROSCHISIS
Introduction
Gastroschisis is a defect in the abdominal wall that usually is
to the right of a normal insertion of the umbilical cord. There
is no membrane or sac and no liver or spleen outside the
abdomen.
-Gastroschisis is associated with no anomalies except
intestinal atresia.
-The herniation is thought to occur as a rupture through an
ischemic portion of the abdominal wall.
-It is probably produced by rupture of an embryonic
omphalocele sac in utero.
-The remnants of the amnion are usually reabsorbed. The
skin may continue to grow over the remnants of the amnion,
and there may be a bridge of skin between the defect and the
cord.
- The small and large bowel herniate through the abdominal
wall defect.
-Having been bathed in the amnionic fluid, and with
compression of the blood supply at the abdominal defect, the
bowel wall has a very thick, shaggy membrane covering it.
-The loops of intestine are usually matted together, and the
intestine appears to be abnormally short.
-The membrane thickens during delay in surgical closure and
compromises the outcome
Complications
-Since the bowel has not been contained intra-abdominally,
the abdominal cavity fails to enlarge, and it frequently cannot
accommodate the protuberant bowel.
-Over 70% of the infants are premature, but associated
anomalies occur in less than 10% of cases.
-Nonrotation of the midgut is present.
-Intestinal atresia occurs frequently, because segments of
intestine that have herniated through the defect become
infarcted in utero.
-Frequently, a staged approach is required. Initially, the
bowel should be covered by forming a tube from silicone-
coated fabric and incorporating the protuberant bowel into
the tube (silo). The end of the tube is tied off. As edema and
shaggy membrane of the protuberant intestine are absorbed,
the bowel will readily reduce into the abdominal cavity.
-A gastrostomy is valuable in postoperative care of the baby,
because gastrointestinal function is often slow to return.
-The death rate for infants with gastroschisis has been greatly
reduced by this technique.
-Poor gastrointestinal function and episodes of sepsis,
presumably from compromised bowel, may occur.
- Total parenteral nutrition may be necessary for several
weeks.
NB.
Diagnosis may be done in utero of the last 2 disorders by
doing an U/S-at 16 and 32 weeks
-Alpha fetal protein raised in both cases.
-Cytology on the amniotic fluid for other associated
disorders.