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8/13/2019 Congental Abdominal Wall Defects
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Congenital Abdominal
Wall Defects
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Introduction
Omphalos was the center stone in the
Temple of Apollo in Delphi. The term
was modified to name the center point of
a newborn infant, from which the termumbilical cord emanated. In Latin, umbo
denoted the ornamental stud at the
center of a shield, from which the term
for the umbilicus area was derived. The
Anglo-Saxon, nafe, meaning hub of a
wheel, was converted to navel.
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Uncommon in other animals, abdominal wall
hernias are among the most common of all
surgical problems. They are a leading cause
of work loss and disability and are sometimes
lethal.
Knowledge of herniasof the abdominal wall
(usual and unusual) and protrusions thatmimic hernias is an essential component of
the armamentarium of the general and
pediatric surgeon. Three types of herniaare
shown below.
http://emedicine.medscape.com/article/775630-overviewhttp://emedicine.medscape.com/article/932680-overviewhttp://emedicine.medscape.com/article/1297226-overviewhttp://emedicine.medscape.com/article/934824-overviewhttp://emedicine.medscape.com/article/934824-overviewhttp://emedicine.medscape.com/article/1297226-overviewhttp://emedicine.medscape.com/article/1297226-overviewhttp://emedicine.medscape.com/article/1297226-overviewhttp://emedicine.medscape.com/article/932680-overviewhttp://emedicine.medscape.com/article/775630-overview8/13/2019 Congental Abdominal Wall Defects
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A 3-month-old girl with a large right
inguinal hernia.
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In this baby with gastroschisis, the bowel is
uncovered and presents to the right inferior
aspect of the cord
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Hernia of the umbilical cord
(omphalocele).
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Recent studies
In a study of 780 laparoscopic inguinalherniorrhaphies (in 569 patients), Coelho et al
investigated the types of intraoperative andpostoperative complications that can result from theprocedure. The authors found that hernias recurredin 14 patients (2.5%) and that intraoperativecomplications occurred in 28 patients (4.9%), the
most common of which was extensivesubcutaneous emphysema. Postoperativecomplications developed in 35 patients (6.2%).Small bowel perforation occurred in 1 patient, and
bladder perforation occurred in another. One cohortmember developed an extensive, preperitoneal
Mycobacterium massiliense infection. No cohortmembers died. The authors concluded that despitehaving a low mortality rate, laparoscopic inguinalherniorrhaphy can result in life-threateningcomplications
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History of the Procedure
Hippocrates used the Greek hernios for bud or bulge todescribe abdominal hernias. Statues of the era portray this
condition. The Ebers papyrus, from approximately 1550 BCE,
detailed the use of a truss. Celsius used transillumination to
differentiate a herniafrom a hydroceleand advocated gradual
pressure (taxis) in the management of incarcerated hernia
(also called irreducible hernia). The earliest recorded surgicalefforts were to reducethe hernia through a scrotal incision, to
remove the sac and the testis, and to close the area with
sutures that spontaneously extruded.
As the church forbade physicians from surgical procedures,
nonphysicians (barbers) began developing therapy for surgical
problems. De Chauliac advocated escharotics with gradual
cicatrization accompanied by prolonged bed rest as the
solution for inguinal hernias. Par followed the operation of
Gerald of Metz using a cerclage wire of gold to retard further
intestinal protrusion into the scrotum.
http://emedicine.medscape.com/article/428055-overviewhttp://emedicine.medscape.com/article/426142-overviewhttp://emedicine.medscape.com/article/1015147-overviewhttp://emedicine.medscape.com/article/178393-overviewhttp://emedicine.medscape.com/article/149608-overviewhttp://emedicine.medscape.com/article/1534321-overviewhttp://emedicine.medscape.com/article/1534321-overviewhttp://emedicine.medscape.com/article/1534321-overviewhttp://emedicine.medscape.com/article/1534321-overviewhttp://emedicine.medscape.com/article/149608-overviewhttp://emedicine.medscape.com/article/178393-overviewhttp://emedicine.medscape.com/article/1015147-overviewhttp://emedicine.medscape.com/article/426142-overviewhttp://emedicine.medscape.com/article/428055-overview8/13/2019 Congental Abdominal Wall Defects
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In 1700, Littre reported an omphalomesenteric duct trapped in ahernia. Richter described an incarcerated but nonobstructinghernia in 1785. Hunter, in 1756, detailed the embryologic originof the indirect inguinal hernia. DeGimbernat advocated cuttingthe ligament that is eponymically associated with him inmanagement of incarcerated femoral hernia. Teale reported thefirst prevascular femoral hernia in 1846.
Other eponyms associated with inguinal hernias relate toanatomical descriptions by Camper (fascia) (1801), Cooper(ligament) (1804), Cloquet (hernia) (1817), Grynfeltt (hernia)(1866), Hesselbach (triangle) (1814), Laugier (hernia) (1833),Nuck (canal) (1650-1692), Petit (hernia) (1783), and Scarpa(fascia) (1814). Scarpa also previously described a slidinghernia and a spigelian hernia in 1645.
The advent of antisepsis by Lister in 1865 paved the way for amore precise surgical approach to hernia. Finally, physicianscould expect success of an operation not being disrupted by
infection. In 1871, Marcy felt that closure of the fascia adjacentto the internal ring would provide a reliable repair of the inguinalhernia. Over a decade later, Bassini (1884) formulated anapproach to hernia repair that remains the foundation of themodern hernia repair, namely, reconstruction of the floor of theinguinal canal.
http://emedicine.medscape.com/article/1534281-overviewhttp://emedicine.medscape.com/article/1534281-overviewhttp://emedicine.medscape.com/article/1534281-overviewhttp://emedicine.medscape.com/article/1534281-overview8/13/2019 Congental Abdominal Wall Defects
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Problem
Operative management of hernias,despite being described since antiquity
and constituting an essential part of the
general surgeon's repertoire of operations,
remains controversial. By definition, ahernia is an abnormal protrusion from
one anatomical space to another. Variants
on the definition of hernia exist with
regard to congenital abdominal walldefects. In this lecture, we will define
these protrusions, their presentations, and
their treatment.
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Note the translucent sac in this baby with
a large omphalocele.
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Note a baby with gastroschisis(the midgut viscera
protrude through a central abdominal fascial defect
and are not covered by a sac)
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Frequency
As much as 10% of the population developssome type of hernia during life. More than ahalf million hernia operations are performedin the United States each year. Fifty percentare for indirect inguinal hernias, with amale-to-female ratio of 7:1, while 25% arefor direct inguinal hernias. Fourteen percentare umbilical (female-to-male ratio, 1.7:1),5% are femoral (female-to-male ratio,1.8:1), and 10% are incisional (female-to-male ratio, 2:1). The prevalence of allvarieties of hernias increases with age.
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Etiology of the inguinal canal pathology
The embryology of the groin and of testicular
descent largely explains indirect inguinal hernias.An indirect inguinal hernia is a congenital herniaregardless of the patient's age. It occurs because of
protrusion of an abdominal viscus into an open
processus vaginalis. If the processus containsviscera, it is called an indirect inguinal hernia. Ifperitoneal fluid fluxes between the space and theperitoneum, it is a communicating hydrocele. Iffluid accumulates in the scrotum or spermatic cord
without exchange of fluid with the peritoneum, it isa noncommunicating scrotal hydrocele or ahydrocele of the cord. In a girl, fluid accumulationin the processus vaginalis results in a hydrocele of
the canal of Nuck.
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The inguinal canal forms by mesenchymecondensation around the gubernaculum,which is Latin for rudder because it guidesthe testis into the scrotum. During the firsttrimester, the gubernaculum extends fromthe testis to the labioscrotal fold. The
processus vaginalis and its fascial coveringsalso form during the first trimester. Abilateral oblique defect in the abdominalwall develops during the sixth or seventhweek of gestation as the muscular wall
develops around the gubernaculum. Theprocessus vaginalis protrudes from theperitoneal cavity and lies anteriorly,laterally, and medially to the gubernaculum
by the eighth week of gestation.
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Pathophysiology of inguinal hernias
The pinchcock action of the musculature of theinternal ring during abdominal muscularstraining prohibits protrusion of the intestine intoa patent processus. Paralysis or injury to themuscle can disable the shutter effect. In addition,the transversus abdominis aponeurosis flattensduring tensing, thus reinforcing the inguinalfloor. A congenitally high position of theaponeurotic arch might preclude the buttressing
effect. Neurapraxic or neurolytic sequelae ofappendectomy or femoral vascular proceduresmay contribute to a greater incidence of hernia inthese patients.
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Repetitive stress as a factor in herniadevelopment is suggested by clinical
presentations. Increased intra-abdominalpressure is seen in a variety of disease states andseems to contribute to hernia formation in these
populations. Elevated intra-abdominal pressureis associated with chronic cough, ascites,
increased peritoneal fluid from biliary atresia,peritoneal dialysis or ventriculoperitonealshunts, intraperitoneal masses or organomegaly,and obstipation. (See images below.) Otherconditions with increased incidence of inguinal
hernias are extrophy of bladder, neonatalintraventricular hemorrhage, myelomeningocele,and undescended testes. A high incidence (16-25%) of inguinal hernias occurs in prematureinfants; this incidence is inversely related toweight.
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A 6-month-old boy with a
ventriculoperitoneal shunt, decreased
activity, and acute scrotal swelling.
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A 6-month-old boy with a ventriculoperitoneal shunt, decreased
activity, and acute scrotal swelling (same patient as in above image).
Abdominal radiograph shows incarcerated shunt within a
communicating hydrocele. Repair of the hydrocele relieved the
increased intracranial pressure.
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The rectus sheath adjacent to groin hernias is thinnerthan normal. The rate of fibroblast proliferation is lessthan normal, while the rate of collagenolysis appearsincreased. Sailors who developed scurvy had anincreased incidence of hernia. Aberrant collagen states,such as Ehlers-Danlos syndrome, fetal hydantoinsyndrome, Freeman-Sheldon syndrome, Hunter-Hurlersyndrome, Kniest syndrome, Marfan syndrome, andMorquio syndrome, have increased rates of hernia
formation, as do osteogenesis imperfecta, pseudo-Hurler polydystrophy, and Scheie syndrome. Acquiredelastase deficiency also can lead to increased herniaformation. In 1981, Cannon and Read found thatincreased serum elastase and decreased alpha1-
antitrypsin levels in people who smoke contribute toan increase in the rate of hernia in those who smokeheavily. The contribution of biochemical or metabolicfactors in the creation of inguinal hernia remainsspeculative.
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Umbilical hernias
Umbilical hernias in children are secondary to failure of
closure of the umbilical ring, but only 1 in 10 adultswith umbilical hernias reports a history of this defect asa child. The adult umbilical hernia occurs through acanal bordered anteriorly by the linea alba, posteriorly
by the umbilical fascia, and laterally by the rectussheath. Proof that umbilical hernias persist from
childhood to present as problems in adults is only hintedat by an increased incidence among black Americans.Multiparity, increased abdominal pressure, and a singlemidline decussation are associated with umbilicalhernias.
Congenital hypothyroidism, fetal hydantoin syndrome,Freeman-Sheldon syndrome, Beckwith-Wiedemannsyndrome, and disorders of collagen and polysaccharidemetabolism (such as Hunter-Hurler syndrome,osteogenesis imperfecta, and Ehlers-Danlos syndrome),should be considered as possibilities in children withlarge umbilical hernias.
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Congenital abdominal wall defects
The underlying embryogenic factor inomphalocele and gastroschisis is deficientclosure of the developing anterior wall at theumbilical stalk. Variations in lateral foldmigration can result in omphalocele and
gastroschisis.4 In addition, most children withomphalocele and all children withgastroschisis have intestinal malrotation, astheir extracoelomic location precludes normalattachment of the intestines to the posteriorperitoneum.
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Improper development of other portions of the abdominal wallleads to specific anomalies. In 1967, Duhamel proposed thatmaldevelopment of the superior (cephalad) of the 4 folds
producing the abdominal wall leads to the thoracic, sternal and
diaphragmatic, and abdominal wall defects that make up theupper midline syndrome or pentalogy of Cantrell. In thissyndrome, there is a bifid sternal cleft, anterior diaphragmaticdefect, anterior pericardial defect, epigastric omphalocele, andcongenital cardiac defects. Maldevelopment of the inferior(caudal) fold produces pelvic, hindgut, sacral, genital, and
bladder defects. Lower midline syndrome includes a
hypogastric omphalocele, extrophy of the bladder or cloaca,vesicointestinal fissure, colonic atresia, imperforate anus, sacralvertebral defects, and often meningoceles.
Lateral fold maldevelopment results in omphalocele andgastroschisis. It has been postulated that an omphalocele resultsfrom persistence of the umbilical stalk in the somatopleure.
Approximately 20% of infants with omphaloceles have anassociated chromosomal abnormality, such as trisomy 13,trisomy 18, trisomy 2, or Klinefelter syndrome. Anomphalocele-exstrophy-imperforate anus-spinal defects(OEIS) complex is characterized by a combination ofomphalocele, exstrophy of the bladder, an imperforateanus, and spinal defects.
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Over 50% of infants with omphaloceles have associatedneurologic, urinary tract, cardiac, and skeletal anomalies. The
liver is present in the omphalocele sac in 35% of patients. Insmall omphaloceles, there is a high coincidence of Meckeldiverticulum. Maternal smoking is associated with an increasedprevalence of omphalocele and gastroschisis. An increasedincidence of abdominal wall defects is related to surface wateratrazine and nitrate levels.6
Gastroschisis is thought to be the result of a failure of theumbilical coelom to develop to an appropriate size. Theintestine then ruptures out of the body wall to the right of theumbilicus, where a slight weakness exists secondary toresorption of the right umbilical vein early in gestation.Gastroschisis is associated with intestinal atresias in 10-15% ofcases, likely due to an interruption of the vascular supply to the
intestine. Experimentally, administration of the insecticidemethylparathion has produced gastroschisis. Transplacentaltransmission of such teratogens helps explain gastroschisis insiblings with different fathers.
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Other hernias
Aberrant formation of the decussations of the linea alba,leading to a midline pattern of single anterior and posterior
lines, predisposes to the formation of epigastric hernias
(epiploceles). Abnormal orientation of the semilunar and
semicircular lines, in combination with obesity, increased
intra-abdominal pressure, aging, and rapid weight loss,
leads to the production of spigelian hernias. Internal supravesical hernias probably arise from congenital
deficiency in the fasciae. The perihernial fasciae or
musculature may be malformed in lumbar, femoral, and
other abdominal hernias. Interparietal hernias are often a
product of ectopic testicular descent. Multiparity and age
produce laxity of the pelvic floor to cause obturator herniasand perineal hernias.
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Presentation
History and physical examination
remain the best means of diagnosing
hernias. The review of systems should
carefully seek out associated conditions,such as ascites, constipation, obstructive
uropathy, chronic obstructive
pulmonary disease, and cough.
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Inguinal hernia
The diagnosis of hernia is usually made because apatient, parent, or provider sees a bulge in theinguinal region or scrotum. This bulge may beintermittent as the herniating viscus may or maynot enter the space depending on intra-abdominal
pressure. In infants, the only symptom of a herniamay be increased irritability, especially with alarge hernia. Hernias in older children and adultsmay be accompanied by a dull ache or burning
pain, which often worsens with exercise or
straining (eg, coughing). Neuralgia of theilioinguinal nerve may present with a suddenstabbing pain in the distribution.
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A 5-years-old boy with a history of irritability
and vomiting for 36 hours. Local signs of
this magnitude preclude reduction attempts.
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A boy of 6 months with bilateral inguinal
hernias
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A child with 48 hours incarcerated inguinal
hernia. The bowel necrosis occurred.
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Hydrocele
A hydrocele usually transilluminates onexamination. However, gas-filled intestines alsotransilluminate, thus precluding diagnosticaspiration. If the scrotal size vacillates or one cansqueeze fluid from the sac into the peritoneum, acommunicating hydrocele is present.Communicating hydroceles without an obvioushernia component should be repaired electively.Hydroceles are insignificant if they are present at
birth, bilateral, soft, and peritesticular; do notpersist beyond 6 months; and do not fluctuate in
size. Since most physiologic noncommunicatinghydroceles resolve spontaneously, an operation isgenerally confined to those older than 1 year,those that develop communication, or those thatappear painful to the child (see image below).
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Bilateral hydroceles in a boy of 2 years
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An acute hydrocele may present in childhood as
a rapidly growing, painful scrotal swelling
simulating an incarcerated hernia. Palpation of
the cord structures at the internal ring while
assessing their mobility helps distinguish
between these 2 entities. A hydrocele is more
mobile, has a defined proximal margin, and is
not thick. A hydrocele of the cord presents in the
inguinal canal as a nontender, rubbery, round
mass.
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An abdominoscrotal hydrocele extends from the
abdominal cavity through the inguinal canal into
the scrotum. With an infant, a digital rectal
examination with careful internal examination of
the ring can differentiate an incarcerated hernia
from a hydrocele. The child should have an
operation for clarification if the situation is
equivocal or if the intra-abdominal component is
causing mass effect on other organs or obstructivesymptoms.
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Other hernias
Hernias are the leading cause of intestinal
obstruction in the world. Hidden hernias, such as
obturator, femoral, or lumbar hernias, should be
considered as causes of bowel obstruction.
Intense pain is suggestive of strangulation with
ischemic bowel. Torsion of the bowel on entry
into the sac may lead to precipitous symptoms,
while a more gradual onset of pain arises from
progressive lymphatic, venous, and then finally
arterial compromise secondary to occlusion at the
neck of the sac.
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Congenital abdominal wall defects
Maternal serum alpha-fetoprotein screening can
help identify ventral wall defects in the fetusduring the second trimester. Prenatalultrasonography can define the location of theabdominal wall defect, the status of the viscera,its involvement with associated structures, and
the presence of additional malformations.Recognition of a small omphalocele or hernia ofthe umbilical cord stalk may not occur until afterdelivery. This may result in compromise of thesmall bowel or damage to an omphalomesenteric
duct as the cord is clamped. Therefore, the cordshould be clamped well away from the abdomenin an infant with an unusual cord base or widenedumbilical cord base to prevent iatrogenic injury tothe intestine.
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Inguinal hernias
In general, the presence of an inguinal hernia in the
absence of mitigating factors dictates repair toprevent the complications of prolonged exposure,such as incarceration, obstruction, and strangulation.
Although pressure reduction of an incarceratedhernia is generally safe, failure to reduce is not
infrequent and mandates prompt exploration. Signsof inflammation or obstruction should obviateattempts at reduction. Difficult reduction should
promptly be followed by repair. Unintentionalreduction of the intestine with vascular compromise
leads to perforation and peritonitis with highmorbidity and mortality rates. En masse reductionfollowing vigorous attempts at reducing a herniawith a small fibrous neck results in ongoingcompromise of the entrapped bowel.
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Umbilical hernias
Umbilical hernia repair in the adult is indicated for
incarceration, a small neck in relation to the size of the hernia,ascites, chromatic skin change, or rupture. The approach to
management of an umbilical hernia in a child relates to the
natural history of umbilical hernias and their importance in
adulthood. Most umbilical hernias close spontaneously in
children during the preschool-aged period. Therefore, repair of
an umbilical hernia is not indicated in children younger than 5
years unless the child has a large proboscoid hernia with thin,
hyperpigmented skin or is undergoing an operation for other
reasons or if the hernia causes familial or social problems. The
size of the fascial defect rather than the size of the external
protrusion predicts potential for spontaneous closure. Walkerdemonstrated that fascial rings measuring less than 1 cm in
diameter usually close, while rings larger than 2 cm seldom
close spontaneously. Therefore, many pediatric surgeons will
repair umbilical hernias with large fascial defects (>2.5 cm)
li th th ll t t