Abdominal wall defects

Abdominal Wall Defects
Dr. Faheem ul Hassan Andrabi
M Ch Resident
Prof Nisar A Bhat
Head & Professor
Pediatric & Neonatal Surgery

During 3rd week, 2 layered disk is converted into 3 layers called
the germ layers

Embryology
mesoderm organizes into
paraxial mesoderm, adjacent to the neural tube
intermediate mesoderm, immediately lateral
to the paraxial mesoderm and
lateral plate mesoderm

Embryology
lateral plate mesoderm splits into 2 layers:
 A parietal (somatic) layer that
will adhere to the ectoderm and a
 Visceral (splanchnic) layer
that will remain adjacent to the gut tube

Embryology
Parietal mesoderm is
closely associated with
ectoderm and is called the
somatopleure
It is this combination that
forms the lateral body folds

Embryology
Lateral body wall folds
begin to move ventrally
to close the ventral body
wall

Embryology
Gut returns to the
embryonic cavity and
the lateral body folds
fuse to form the
abdominal wall

Embryology
If lateral body wall folds fail to grow or fuse,
ventral wall defects arise
Right fold lags behind in development compared
with the left. This may explain why gastroschisis
usually occurs on the right side

Embryology
abnormal closure of the lateral body wall folds
In the thorax ectopia cordis
in the abdomen gastroschisis
In the pelvic region bladder exstrophy

Omphalocele-
Omphalocele is a large defect (>4 cm) covered by
amniotic membrane
It usually contains
midgut and
other abdominal organs including the liver
often the spleen and gonad.

Omphalocele-
Umbilical cord hernia is less than 4 cm and contains
only the midgut,
It is often confused with omphalocele.
The differences are that it contains only midgut, never
liver and
abdominal wall above the defect is normal, (with the rectus muscles
meeting in the midline at the xiphoid)

Omphalocele- Embryology
Omphalocele is caused by a failure of intestinal loops to
return to the body cavity following normal physiological
herniation into the umbilical cord.

Because the loops of bowel are in the cord, they are
covered by membranes (amnion)

Ectopia cordis
Cardiac defects
Omphalocele
Cleft sternum
Diaphragmatic,
pericardial defects

Omphalocele- ultrasound
diagnosis is usually made antenatally by ultrasound
Omphalocele can be distinguished from gastroschisis by the
presence of a sac and from umbilical cord hernia by the presence
of the liver in the defect

Omphalocele- Clinical features
It is the second most common AWD after
gastroschisis.
Incidence is 1 to 2.5 per 5000 live births
there is a male preponderance.
Patients with omphalocele are more likely to be
large for gestational age (macrosomia or > 4 kg
in birth weight

cardiac abnormality 45%
VSD, ASD, ectopia cordis, tricuspid
atresia, coarctation of the aorta,
persistent pulmonary hypertension of the newborn
Chromosomal abnormalities 20%
Musculoskeletal and neural tube defects
Gastroesophageal reflux is more likely

Omphalocele- initial management
A nasogastric (NG) tube should be placed early to
decompress the intestines.
A rectal examination aids this with evacuation of
meconium.
Maintenance of body temperature is especially
important.
Ventilator support and supplemental oxygen should be
supplied as needed.

Omphalocele- initial management
Although the bowel in omphalocele is protected by the
sac, operation is still urgently needed to increase the
chance for primary closure.
Cardiology evaluation for heart defects is necessary,
although the results will not delay repair.
Nonoperative initial treatment (painting the sac with
an antiseptic) is still useful when operative closure is
not possible

Methods to determine whether the fascial closure is
too tight:
a saphenous vein intravenous line that will not drip
by gravity or
intravesical or NG tube pressure greater than 20
cm of H2O
Peak inspiratory pressure > 25 cm of H2O

Omphalocele- Management
If the fascial closure is judged to be too tight,
one can consider only skin closure
prosthetic silo that will allow slow reduction of the
abdominal viscera over a 1-week period.

giant omphalocele is a separate category of defect that
is particularly difficult to treat.
there is no standard definition of this entity in terms
of size or amount of herniated viscera
Giant omphalocele as one with 75% or more of the
liver in the sac

Omphalocele- Options of treatment for GO
painting the sac with antiseptic,
the use of skin flaps with grafting to the open areas
remaining
use of tissue expander
And split-thickness skin grafting

Omphalocele- Treatment of giant omphalocele
Paint and Wait followed by delayed closure usually 6-12
months later when the viscero-abdominal disproportion
normalises
Epithelialization may be promoted by
alcohol dressings
2% mercurochrome silver sulfadiazine
povidone iodine
Currently alginates and other materials are used

Delayed closure
The Lazaro da Silva’s technique consists of the
bilateral longitudinal fibroperitonealaponeurotic
transposition, resulting in three different layers of
closure.

Delayed closure
Other technique is to place a sphygmomanometer
cuff on top of the hernia and compress the hernia
contents by controlled inflation of this cuff daily.
Reduction of the ventral hernia is achieved after
several months after which primary hernia repair is
achieved.

Delayed closure
The use of tissue expanders after initial
nonoperative treatment is described by De Ugarte
The tissue expanders are placed within the
intramuscular layers of the abdominal wall

Operative treatment
Primary closure by
Prosthetic materials like Goretex, Dacron, Marlex,
Teflon
Biodegradable materials like Surgisis

Operative treatment
Staged closure
Skin flaps
Silo/silastic sheet
Sequential manual reduction or ligation of
the sac is performed with or without general
anesthesia.

Gastroschisis; Embryology
The term
gastroschisis is derived
from Greek roots
meaning ”stomach
cleft”, but the correct
term may be
laparoschisis (belly
cleft).

failure of the umbilical coelom to develop.
The elongating intestine then has no space to expand
and ruptures out the body wall just to the right of the umbilicus

An alternate explanation is that
the yolk sac and associated vitelline structures
fail to incorporate into the umbilical cord, thus
allowing the midgut to exit the abdomen at the
point lateral to umblicus

Gastroschisis; Risk factors
● Young maternal age
● Hispanic race
● Poor maternal education
● Low socioeconomic status
● Lack of prenatal care
● Multiparity
● More than one elective abortion
● Short interval between menarche and first pregnancy
● Maternal diet (low alpha-carotene, low total
glutathione, high nitrosamines)
● Low pregnancy body mass index

Gastroschisis; teratogens
● Cyclooxygenase inhibitors (aspirin, ibuprofen)
● Decongestants
● Acetaminophen
● Maternal smoking
● Alcohol
● Illicit drugs (eg, cocaine, amphetamine)
● X-ray irradiation in early pregnancy

Gastroschisis; ultrasound
● Prenatal diagnosis by ultrasound is based on the visualization of
a herniated free-floating bowels without membrane and a
normal umbilical cord

Gastroschisis; ultrasound
●Serial ultrasound is mandatory to rule out complications like
bowel obstruction,
peritonitis,
Bowel perforation and
IUGR.
A diameter greater than 11 mm is a predictive sign for postnatal
complications like obstruction

Gastroschisis: Markers
Elevated AFP and AChE in both maternal serum
and amniotic fluid is seen in ABWD.
The rise is more in Gastroschisis > Omphalocele

Gastroschisis: clinical features
Most common of the abdominal wall defects
The incidence is about 2 to 5 per 10,000 live births
with a male preponderance.
More common in premature newborns

•defect is small (usually less than 4
cm)
•Occurs to the right of the umbilicus
•Abdominal wall musculature is
normal
•No sac or remnant of a sac
•Mid gut is herniated through defect
(Possibly duodenum, stomach, colon
or gonad)

The anomalies associated with gastroschisis are
intestinal atresia (5%)
gastroesophageal reflux (16%) and
undescended testicle (15%), usually corrects
spontaneously
dysmotile bowel

Gastroschisis: initail management
First approach is aimed to prevent
Heat loss
Fluid loss
onset of infection,
ischemic or traumatic injury to the intestine.

Gastroschisis: Initial management
Heat preservation
Resiratory support
Adequate fluid administration
As the patient is usually premature and bowel is exposed
are of prime importance

Start IV line
Place monitoring equipment
Place patient in bowel bag
Place NGT (evacuate stomach)

route of delivery does not affect outcome in Gastroschisis
Cesarean delivery is not mandatory but allows team to be
assembled
rapid transfer from the delivery room to the operating
room (<1 hour) will also lead to a greater likelihood of
primary closure

Gastroschisis: closure
The aim of surgical treatment of gastroschisis is to restore
the integrity of the anterior abdominal wall and reducing
the herniated viscera within the abdominal cavity.
The surgeon can proceed with the primary fascial closure or
reduction of the content over time by a Silo.

Silo allows a gradual return of the viscera in the abdomen
without respiratory and hemodynamic instability
It is important to monitor the intra-abdominal pressure
during surgery.
The high intra-abdominal pressures may be responsible
also for hemodynamic alterations during primary closure

the best approach to treat gastroschisis remains
controversial
Primary closure of the abdominal wall is still considered to
be the ideal correction of gastroschisis by some authors.
Staged closure is associated with
fewer days on mechanical ventilation,
Decreased length of hospital stay,

Gastroschisis: Silo closure
IVP has been successfully used as a criterion to gauge
whether to perform primary or staged closure.
Initially proposed by Nakayama et al., the IVP when kept
below 20 mm Hg, it was associated with lower rates of
complication after primary closure.
Nakayama M, Horikawa D, Nagai H, Tamiya K, Fujita S, Namiki A.
Utility of intra-bladder pressure monitoring during closure of abdominal
wall defects in newborn infants. Masui. 1992;41:1647-50

Gastroschisis:
Close primarily if possible
Silo reduction is good alternative
Don’t make the closure too tight
Wait to feed the patient (14 days)
Slow advances on feeds
Expect high residuals and bilious aspirates
Rectal stimulation

Gastroschisis: post-op complications
Necrotizing Enterocolitis
Short gut syndrome
Malabsorption
Obstruction
TPN-associated cholestasis
Developmental delay

Gastroschisis: post-op complications
More complicated post-operative course is seen in
Intestinal perforation
Atresia
Necrotic Segments
Volvulus
Characterized by: prolonged ileus & time to tolerate
feeds, longer length of stay, increased infectious
complication & mortality.

Bladder Exstrophy
Bladder exstrophy is a rare midline defect
It exists as part of a larger spectrum of
abnormalities, collectively known as the
exstrophy-epispadias complex (EEC).

EEC- Epidemiology
Incidence of 1 in 10,000 and 1 in 50,000 live births
Male to female ratio of between 2-4:1
Familial occurrence has been reported
Reports of bladder exstrophy among identical
twins have been demonstrated
However, no clear pattern of inheritance has been
characterized

EEC- risk factors
Risk factors include
Caucasian race
young maternal age
maternal multiparity
assisted-reproductive technologies such as in
vitro fertilization

EEC- embryology
Rupture of the cloacal
membrane after fusion
with the urorectal
septum results in
bladder exstrophy,
rupture before fusion
gives rise to the more
severe presentation of
cloacal exstrophy

EEC- clinical presentation
The three most common presentations of EEC are
epispadias,
classic bladder exstrophy (CBE), and
cloacal exstrophy (CE)
Complete epispadias is the least severe form of EEC
CBE (Classical bladder exstrophy) is the most common
presentation of EEC.
Cloacal exstrophy CE is the most severe of the three
presentations

Generally full term,
an everted posterior bladder plate is seen in the lower midline
The mucosa of the exposed bladder is typically smooth and pink.
The umbilical cord exits from the superior-most border of the
bladder plate, and a small umbilical hernia may be present.

There is significant widening of the pubic symphysis
Anus is anteriorly displaced.
Levator ani complex is also divergent, leading to weakness in the
pelvic floor.

EEC- associations
inguinal hernias
Renal anomalies including ectopic, horseshoe,
hypoplastic, dysplastic kidneys, and megaureters may
be observed
Vesicoureteral reflux occurs in the vast majority of
children after bladder closure,
Due to abnormal uretero-vesical angle and short submucosal
tunnel

Due to Continued exposure and chronic inflammation
bladder may become
thickened and polypoid
Later on Fibrotic and rigid bladder plate that is
unsuitable for closure

EEC- male genital defects
open and everted urethral plate can be seen joining the
exposed bladder.
Phallus is short with a flattened, everted glans.
Chordee may be present
The prepuce is located on the penile ventrum
The ejaculatory ducts are typically normal and exit at
the exposed verumontanum in the posterior urethra.

EEC- male genital defects
The base of the penis and scrotum are widely separated
Lateral displacement of corporal bodies under pubic
bones
In CE, the phallus is typically split completely between
the diastatic pubis, with each half often of unequal size

EEC- female genital defects
The clitoris is bifid with
divergence of the mons pubis, labia, and clitoral halves
The urethra and vagina are shortened
introitus is anteriorly displaced.
Vaginal orifice is often stenotic.
The uterus and adnexa are typically normal(though vaginal and
uterine duplication have been reported).
Uterine prolapse occurs commonly in female patients, secondary to the inherent
weakness in pelvic floor support.

EEC-
The ureters in BE and CE patients enter the bladder at
an abnormal angle leading to vesicoureteral reflux
(VUR) in all patients following bladder closure
the upper urinary tract is malformed in about one third
of all EEC cases (more commonly in CE patients)

EEC- musculoskeletal
The bladder and urethra are exposed through a
triangular defect in the lower abdominal wall.
The opening extends from the umbilicus above
to the intra- symphyseal band inferiorly.

Umbilical hernias are common
Divergent distal rectus abdominis muscles.
BE patients have a mean pubic diastasis of 4.8
cm,
External rotation of both the anterior and
posterior segments of the pelvis (Box or open
Book Pelvis)

larger sacrum
malrotation and asymmetry in bone segments
(CE> BE)
pelvic floor musculature abnormalities (CE> BE)
which contribute to incontinence in these
patients and predispose females to uterine
prolapse

Anteriorly displaced anus and anal sphincter
predisposes exstrophy patients to fecal
incontinence.
BE patients occasionally have omphalocele,
imperforate anus, rectal stenosis, and rectal
prolapse ,

CE patients almost always have some
gastrointestinal defect.
These include omphalocele, imperforate anus,
rudimentary hindgut
Duplicated cecum, can also be found separating
the CE patient’s two bladder plates

EEC- neurospinal abnormalities
Approximately 7% of BE patients will have a spinal
abnormality (spina bifida occulta, scoliosis, and hemivertebrae)
Nearly all CE patients demonstrate significant
neurospinal deficits including neural tube defects,
vertebral anomalies

These associated neurospinal anomalies necessitate
prompt neurological evaluation with spinal US and MRI
These anomalies can further aggrevate urinary and
bowel incontinence

Antenatal US
absence of bladder filling,
low-set umbilicus,
widened pubic rami,
small genitalia,
lower abdominal mass
Prolapsed ileum in CE patients may look like an “elephant trunk” on
US .

EEC- initial management
the umbilical cord should be ligated with a silk suture
instead of traditional plastic clip
The exposed bladder mucosa should be moistened with
saline and protected with a nonadherent sheet of
plastic
Renal US may be obtained to exclude hydronephrosis
and/or other upper tract abnormalities.
Prophylactic antibiotics should be administered.

EEC- timing of primary closure
proponents of early bladder closure (within 72 h) argue
that prompt closure allows:
earlier bladder cycling,
improved bladder expansion, and
decreased risk of precancerous changes
Those delaying bladder closure state that
it does not cause metaplastic changes,
can allow for concomitant epispadias repair

EEC- Modern staged reconstruction of
Exstrophy MSRE
The first stage is the abdominal wall and bladder
closure
Females also undergo genitoplasty and urethroplasty with this
first procedure.
The second stage in males is to close the urethral
epispadias with a modified Cantwell-Ransley repair at 6
to 12 months of age
Following epispadias repair, the patient’s bladder
capacity is measured annually

Exstrophy MSRE
In third stage MSRE a
continence procedure such as the Young-Dees-
Leadbetter BNR, is carried out (usually before school
age and bladder capacity of 85 ml).
This stage is combined with ureteral reimplantation to
repair VUR.

Exstrophy MSRE
Children who are not candidates for BNR or who fail to
achieve urinary continence after the procedure may
require bladder neck transection, AC, and continent
Urinary diversion CUD.

EEC- Complete Primary Repair of Exstrophy
(CPRE)
CPRE combines
primary abdominal wall and bladder closure with
epispadias repair and
partial tightening of the bladder neck.
Furthermore, bilateral ureteral reimplantation can
safely be done

(CPRE)
Advantages of CPRE
may decrease costs,
decrease the morbidity associated with multiple
operations,
stimulate early bladder growth.

(CPRE)
While CPRE is thought to reduce the number of
surgeries for BE, many children
still require surgery for resulting
hypospadias,
Persistent vesicoureteral reflux,
incontinence, or
failed primary closure

EEC- Osteotomy
The advantages of osteotomy are
easy re-approximation of the symphysis
diminished tension on the abdominal wall closure,
placement of the urethra deep within the pelvic
ring,
enhancing bladder outlet resistance

EEC- Osteotomy
Osteotomy should be done
when bladder closure is performed more than 72 h
after birth.
pelvis is not malleable or
if the pubic bones are greater than 4 cm apart at the
time of initial examination

EEC- Osteotomy
The patient remains supine in traction for approx 4 wk
(to prevent dislodgement of tubes and destabilization of the pelvis ).
The external fixator is kept on for approx 6 wk until
adequate callous is seen.
Newborns who undergo closure without osteotomy in
the first 48 to 72 h of life are immobilized in Modified
Bryant’s traction (hips have 90° of flexion).
MBT should be maintained for 4 wks

EEC- Osteotomy
Modified Buck’s traction along with external fixating device used in 18-mo-old with
prior failed exstrophy closure.

EEC- Osteotomy
Modified Bryant’s traction in newborn with bladder exstrophy not
requiring osteotomy.

EEC- Complications
The most common complications of both Cantwell-
Ransley and complete penile disassembly epispadias
repair are
Persistent chordee,
urethrocutaneous fistula, and
wound dehiscence
glans and/or corporeal ischemia in Mitchell repair’s
(due to venous congestion) .

EEC- Complications
Major contributing factors for dehiscence include
wound infection,
abdominal distension,
bladder prolapse, and
loss of ureteral and/or suprapubic catheters within 6
days of closure

EEC- Complications
Other complications are
bladder prolapse,
bladder outlet obstruction, and
vesicocutaneous fistula
penile loss following penile disassembly

EEC- Complications
Other complications are
bladder prolapse,
bladder outlet obstruction, and
vesicocutaneous fistula (2-26%)
penile loss following penile disassembly
Diminished fertility
development of adenocarcinoma and transitional
cell carcinoma (undergone augmentation cystoplasty).

Cloacal exstrophy
is a rare condition
occurring in 1 of 200,000 to 400,000 live births
Cloacal exstrophy is also
referred to as the OEIS complex (omphalocele,
exstrophy, imperforate anus, and spinal defect)

Cloacal exstrophy
Survival rates were initially dismal
With advances in the neonatal care survival rates are
approaching 90%

Cloacal exstrophy; Prenatal diagnosis
Early prenatal diagnosis allows parental counseling and
allows for consideration of MTP
Diagnosis has major Criteria and Minor Criteria

Major Criteria
Nonvisualization of the bladder
a large, midline, infraumbilical AWD
or cystic anterior abdominal wall structure
omphalocele and myelomeningocele

Minor Criteria
lower extremity defects
renal anomalies
Ascites
widened pubic arches
Narrow thorax
Hydrocephalus and
single umbilical artery

Cloacal exstrophy; Initial management
enclosing the infant’s lower torso in a bowel bag or
moistening surfaces with saline and covering with
sterile plastic wrapping
Note genetic sex and size of hemibladder plates
Determine renal function, electrolyte, and hematologic
status
Karyotyping if gender has not been previously
determined

Cloacal exstrophy; Initial management
MRI may be advisable for detection of occult lesions
Parents should be counseled regarding
gender assignment,
surgical reconstruction,
potential functional deficits, and
Expected quality of life.

Cloacal exstrophy; principles of repair
The surgical management undertaken in the newborn
period (48 to 72 hours)
Early operation minimizes bacterial colonization of
exposed viscera and may decrease the need for pelvic
osteotomy

Cloacal exstrophy; Goals of repair
secure abdominal wall and
Bladder closure,
preservation of renal function,
prevention of short gut syndrome,
creation of functionally and cosmetically acceptable
genitalia, and
attainment of urinary and fecal continence

Cloacal exstrophy; Goals of repair

Abdominal wall defects

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