Anterior abdominal wall defects

1. ANTERIOR ABDOMINAL DEFECTS
*GASTROSCHIS
IS
*OMPHALOCELE
Dr. Hussein Iman SHO – SURGERY
Dr. Felix – Paed Surgeon

2. Omphalocele (Exomphalos)
Incidence: 1 in 5000 live births
• Gut contents are normally extruded out in
the 5th week of fetal life
•During this time the pleuro peritoneal
cavities which are in unison get divided into
thoracic
and abdominal cavities by the newly formed
diaphragm (around 7th week)
•around 9th week, the extruded gut contents
come back into the abdominal cavity.
•If there is failure on part of the gut contents to come back into the abdominal
cavity in entirety, then a part of the gut remains outside.
• This mass of tissue is ensheathed by a membrane called amnion
•this membrane affords protection against both infection and loss of extracellular
fluid.
• typically the umbilical cord is at the apex of the mass.

3. Gastroschisis
Incidence: 1 in 5000 live births
• Gut contents are normally extruded out in the 5th
week of fetal life
•During this time the pleuro peritoneal cavities which
are in unison get divided into thoracic and
abdominal cavities by the newly formed diaphragm
(7th week)
• around 9th week, the extruded gut contents come
back into the abdominal cavity.
• unlike an omphalocele, gut contents enter back in
entirety at 9th week.
•owing to a disruption in blood supply from the omphalomesenteric artery, there is
ischemia and atrophy of several layers of abdominal wall at base of the umbilical
cord.
• This leads to an area of weakness in the abdominal wall.

4. Gastroschisis
•It is through this weakness that gut
contents pouch out later in foetal life. There
is no membrane covering the mass and
therefore no protection is afforded against
infection or loss of extra cellular fluid.
•As the gut lies exposed (without a
membrane) it tends to irritate the uterine
lining increasing the chances of premature
delivery.
•typically the umbilical cord is at one side of
the mass

5. Associated congenital anomalies
•Are more with omphalocele than Gastroschisis
1. Bowel atresia
2. Imperforate anus
3. Congenital heart disease (20%)
4. Bladder exostrophy
5. Beckwith Weidman syndrome: Mental retardation, hypoglycemia, congenital
heart disease, large tongue and omphalocele
6. Other defects predominantly involving the gut such as malrotation.

6. Antenatal diagnosis
•Involves assessment of α fetoprotein levels which are high in
abdominal wall defects.
•Maternal Serum α fetoprotein level is also assessed but is less sensitive than α
fetoprotein from amniotic fluid.
• Levels of these markers are high in omphalocele.
• USG helps in definitive diagnosis
• USG additionally helps in picking up coexistent congenital anomalies.

7. Preoperative care
•Obtain I.V. access
• Assess for associated congenital anomalies
• Manage respiratory insufficiency.
• Aspirate from the nasogastric tube.

8. Perioperative care
1. Anticipate difficulty airway in a neonate with large tongue as in Beckwith
Wiedemann syndrome
2. IV or inhalational induction may be preferred. Rapid sequence induction is also
found to be useful.
3. Endotracheal intubation (nasal tube) and IPPV are required.
4. Maintenance with volatile anesthetic with oxygen and air.
5. If extubation is not planned for at the end of surgery then judicious use of opoids
is accepted.
6. A caudal epidural confers good post operative analgesia.
7. An arterial line is helpful in monitoring blood pressure and arterial blood gases.
8. Since a large volume of tissue is exposed to room air, the amount of loss in
terms of fluids can be substantial and need to be replenished.
9. To this end, organ perfusion needs to be maintained at optimal levels, especially
so when the abdominal contents are compressing the inferior vena cava and
compromising cardiac output.

9. Perioperative care
11.During surgery intra-abdominal pressure increases, lung compliance falls, and
ventilation usually becomes more difficult. Ventilatory rate and pressure along
with the FIO2 usually need to be increased. A slight degree of head up may be
helpful.
12. To summarise, the chief concerns in these surgeries are fluid loss replacement
and maintaining ventilation.
13.Fluid loss must be minimised by covering the gut contents outside the
abdominal cavity with a sterile bag containing saline.

10. Perioperative care
14.Fluid loss replacement is best done with balanced salt solution with 5% albumin.
15.It is best to avoid N2O to prevent further abdominal distension.
16.Adequate muscle relaxation is important to facilitate better closure of abdominal
wall, but if the defect is large then a forceful closure may hamper circulation to
bowel, Kidneys and lower limb. In fact use of pulse oximetry to assess perfusion
in the lower limb is avidly advocated.

11. When to attempt a primary closure in a single
sitting as opposed to multiple sittings…?
• Intragastric pressure is measured.
• If it is below 20 mm of Hg then a primary closure is done in a single sitting.
• If it is above 20 mm of Hg then a delayed closure technique is adopted.
If closure is difficult through conventional approaches…?
• A wide silo is incorporated into the abdominal wall covering the viscera.
• Every 2-3 days the silo is reduced either bedside or on the OT table with or
without Ketamine.
• A hurried reduction impedes circulation and compromises oxygenation
• After several stages of such reduction final solution is to achieve complete
closure under general anesthesia with muscle relaxation.
• Surgery may not be an immediate solution, but probably remains the only
effective one.

12. Post operative care
• Coexistent pulmonary hypoplasia (especially in Omphalocele) requires careful
consideration during ventilation
Too little risks inadequate
oxygenation
Too much results in barotrauma
• Better not to extubate
• Postoperative complications include
 Post operative hypertension
 Edema of extremities

13. Post operative care
• Post operative hypertension
Increased intra abdominal pressure
Decreased renal perfusion
Increased renin secretion
Activation of renin-angiotensin-aldosterone
system
Hypertension

14. THANK YOU