Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Pediatric Surgery 1 Abdominal Wall Defects PPT-Powerpoint Presentations and lecture notes
ABDOMINAL WALL DEFECTS :
OMPHALOCELE AND GASTROSCHISIS
ABDOMINAL WALL DEFECTS
? A type of congenital defect that allows the abdominal organs
to protrude through an unusual opening (blue arrows)that
forms on the abdomen.
CONTENTS
? Embryology
? Types
? Gastroschisis
? Omphalocele
? Management
? Outcome
? Differences
EMBRYOLOGY
? Closure of the body wall begins at 3 weeks' gestation and results
from growth and longitudinal infolding of the embryonic disks.
? The cephalic fold forms the thoracic
and epigastric wall.
? The lateral folds form the lateral
abdominal walls.
? The caudal fold contributes the
hindgut, bladder, and hypogastric
wall.
? These four folds meet in the midline to
form the umbilical ring.
? During 6th week of gestation, rapid growth
of intestines causes herniation of the
midgut into the umbilical cord.
? Week 10, the midgut is returned to the
abdominal cavity and the small bowel and
colon assumes a fixed position.
? Any disruption in process may result in an
abdominal wall defect.
TYPES
1. Ectopia cordis thoracis ? cephalic
fold defect.
2. Pentalogy of Cantrell- cephalic fold
defect.
3. Omphalocele ? Failure of folding.
4. Umbilical cord Hernia ? Small
defect and normal abdominal wall.
5. Gastroschisis ?
6. Cloacal exstrophy ? caudal fold
defect.
GASTROSCHISIS- Most common
? Incidence : 2 to 4.9 per 10,000 live
births.
? Herniation of intestinal loops
through full-thickness defect in
anterior abdominal wall.
? Defect lateral to the
umbilicus (right>left), usually
less than 4cm in size.
? No sac covers the extruded
viscera (usu. only intestines).
? Preterm babies (28%).
? Young mothers (<25years).
Etiology:
? In-utero vascular accident.
2 theories
1. Involution of the right umbilical vein causes
necrosis in the abdominal wall leading to a
right-sided defect.
2.Right omphalomesenteric artery prematurely
involutes
? Other theories:
?In-utero rupture of omphalocele.
?Abnormal midline fusion of the
abdominal folds.
ASSOCIATED ANOMALIES
? 10-20% - intestinal stenosis or
atresia that results from
vascular insufficiency to the
bowel.
? `Vanishing bowel'- very small
defect strangulates bowel
development.
ANTENATAL CONSIDERATIONS
? Diagnosis can often be made < 20 weeks
of pregnancy by ultrasound.
? Amniotic fluid and serum tests of AFP and
amniotic fluid acetylcholinesterase
(AChE)- raised in abdominal wall defects.
? Opportunity to counsel the family
(Increased risk :
- Intrauterine growth retardation
(IUGR),
- Fetal death, and
- Premature delivery).
? Prepare for optimal postnatal care.
Mode of delivery.
? Optimal mode- debated.
- Proponents of LSCS: Vaginal delivery
may damage bowel.
- Studies have failed to show difference
in outcome between Caesarean and
vaginal delivery.
- The delivery method should be at the
discretion of the obstetrician and the
mother
Timing of delivery
? Considerations :
1. Because bowel edema and peel formation increase
as pregnancy progresses.
2. LBW and preterm negatively influences outcome,
with neonates weighing <2 kg having
- increased time to full enteral feeding,
- ventilated days, and
- duration of parenteral nutrition.
? The presumption is that earlier delivery based on serial
measurements of the bowel may decrease the incidence
of intestinal complications.
PERINATAL CARE
? Outcome depends on - amount of intestinal damage that
occurs during fetal life.
? Combination of exposure to amniotic fluid and constriction
of the bowel at the abdominal wall defect.
? Intestinal damage impaired motility and mucosal absorptive
function prolonged need for total parenteral nutrition and
severe irreversible intestinal failure.
? Prenatal diagnosis provides a potential opportunity
to modulate mode, location, and timing of delivery
in order to minimize these complications.
Neonatal resuscitation and management
? Gastroschisis causes significant
evaporative water losses from
the exposed bowel.
1. Warm saline-soaked gauze,
placed in a central position on the
abdominal wall and wrapped with
plastic wrap.
2. IV Fluid resuscitation.
3. Gastric decompression.
4. Baby right side down- prevent
mesenteric pedicle kinking.
5. IV antibiotics.
SURGICAL MANAGEMENT
? The primary goal of every surgical repair is to
return the viscera to the abdominal cavity while
minimizing the risk of damage to the viscera.
? Options include:
(i) Primary reduction with operative closure of the
fascia;
(ii) silo placement, serial reductions, and delayed
fascial closure;
Primary closure ? with fascial closure
? In neonates considered to possess sufficient intraabdominal
domain to permit full reduction of the herniated viscera.
? Warm bowel and clean the peel; check quickly for intestinal
anomalies.
Primary closure- without fascial closure
? Umbilicus as an
allograft.
? Prosthetic non
absorbable mesh.
? Prosthetic biosynthetic
absorbable options ?
dura or porcine small
intestinal submucosa.
Staged closure
? Bowel placed into
? Spring loaded silo
- Silastic sheet silo
? Delivery room or OT.
? Bowel is reduced once or twice
daily into the abdominal cavity
as the silo is shortened by
sequential ligation.
? Once contents entirely
reduced, definitive closure.
? Usually takes 1-14 days.
Intra-abdominal pressure
? Either as intravesical or intragastric pressure, can be used to
guide the surgeon during reduction.
? Pressures >20 mmHg are correlated with decreased perfusion
to the kidneys and bowel.
? Following reduction, monitor:
- Physical examination,
- Urine output, and
- lower limb perfusion
With a low threshold to reopen a closed abdomen for signs of
abdominal compartment syndrome
? Gangrenous intestinal loop within the silo.
Management of associated intestinal
atresia or perforation
? Upto 10 % cases associated.
? Usually jejunal and ileal.
? Options
- Resection and end to end anastomosis
- Stoma
- Initial gastroschisis repair and 4-5 weeks later, atresia
surgery.
Postoperative Course
? Abnormal intestinal motility.
? Abnormal nutrient absorption.
? Delayed enteral feeding.
? Prokinetics.
? Parenteral nutrition.
OMPHALOCELE- 2nd Most common
? Incidence is 1.5 to 3 per 10,000 live births.
? Omphalocele represents a failure of the body folds to complete
their journey.
? Herniated viscera covered by a membrane consisting of
peritoneum on the inner surface, amnion on the outer surface,
and Wharton's jelly between the layers.
OMPHALOCELE (EXOMPHALOS)
? The umbilical vessels insert into the
membrane and not the body wall.
? The hernia contents include a variable
amount of intestine, often parts of the
liver, and occasionally other organs.
?
OMPHALOCELE (EXOMPHALOS)
? Whatever the insult may be that causes it, this aberration
occurs early in embryogenesis- more associated anomalies.
ANTENATAL CONSIDERATIONS
? Distinguished by presence of sac and
presence of liver.
? Other associated anomalies-
ultrasound especially for cardiac and
chromosomal studies.
? Increased levels of AFP and AChE
? Risks of :
- IUGR (5-35%)
- Fetal death
- Premature labour (5-60%)
PERINATAL CARE
? Neither caesarean nor vaginal delivery superior.
? Most practitioners choose to deliver neonates with large
omphaloceles by cesarean section because of the fear of liver
injury or sac rupture during vaginal delivery.
? Delivery at tertiary perinatal centre- immediate access to expert
care.
? No advantage of preterm delivery.
NEONATAL RESUSCITATION AND MANAGEMENT
? Careful attention to cardiopulmonary status- unsuspected
pulmonary hypoplasia- requires immediate intubation and
ventilation.
? Directed cardiac evaluation:
- auscultation,
- four-limb blood pressures, and
- peripheral pulse examination.
? Dressed with saline soaked gauze and an impervious dressing to
minimize fluid and temperature losses.
? If sac ruptured, then treat as gastroschisis.
? IV fluids and nasogastric tube.
SURGICAL MANAGEMENT
? Treatment options in infants with omphalocele
depend on:
- The size of the defect,
- gestational age, and
- the presence of associated anomalies.
? Options:
1. Primary closure
2. Staged closure
PRIMARY CLOSURE
? Only when the baby is stable and defect is small.
? Steps:
- Excising the omphalocele membrane,
- reducing the herniated viscera, and
- closing the fascia and skin.
STAGED CLOSURE
? If the covering sac is intact, then there is no urgency to perform
operative closure.
? `Escharotic therapy', which results in gradual epithelialization of
the omphalocele sac.
? Usually takes many
months for the sac to
granulate and epithelialize.
? Options:
1. Silver sulfadiazine
2. Mercurochrome
3. Povidone iodine
4. Gentian violet
? Mercurochrome
- scarificant and disinfectant.
- reports of mercury poisoning.
? Povidone iodine - systemic
absorption of the iodine-
transient hypothyroidism.
? Gentian violet ?
Antibacterial and
antifungal.
STAGED CLOSURE
? Sac is epithelialized or sturdy enough to withstand external
pressure
Compression is done with elastic bandages and serially
increased until the abdominal contents are reduced.
VENTRAL HERNIA REPAIR
VENTRAL HERNIA REPAIR
1. Flaps that mobilize the muscle, fascia, and
skin of the abdominal wall toward the
midline and allow midline fascial
closure.
2. Tissue expanders-to
create an abdominal
cavity big enough to
house the viscera.
3. Prosthetic patches in
abdominal wall.
Long-term outcomes
GASTROSCHISIS
? Generally excellent.
? Many patients with atresia do very
well as long
as the bowel is not irreversibly
damaged during fetal life.
? Majority - will achieve normal
growth and development after an
initial catch-up period in early
childhood.
Long-term outcomes
OMPHALOCELE
? Most infants recover well with no long
term issues, provided that there are no
significant structural or chromosomal abnormalities.
? Long term medical problems occur in patients with large
omphaloceles:
- gastroesophageal reflux,
- pulmonary insufficiency,
- recurrent lung infections or asthma, and
- feeding difficulty with failure to thrive,
reported in up to 60% of infants with a giant omphalocele.
OMPHALOCELE
GASTROSCHISIS
INCIDENCE
1.5-3: 10,000
2 -4.9: 10,000
SAC
Present
Absent
ASSOCIATED ANOMALIES
Common
Uncommon
DEFECT
At umbilicus; 1-15 cm Right of umbilicus; <4cm
MATERNAL AGE
Average
Younger
SURGICAL MANAGEMENT
Non urgent
Urgent
PROGNOSTIC FACTORS
Associated anomalies
Bowel condition
MORTALITY
<5%
~ 25%
This post was last modified on 08 April 2022