Ventral Abdominal Wall DefectsZachary J. Kastenberg,

MD,* Sanjeev Dutta, MD,

MBA†

Author Disclosure

Dr Kastenberg has

disclosed no financial

relationships relevant

to this article. Dr.

Dutta has disclosed he

is a consultant for

Stryker Endoscopy.

This commentary does

not contain

a discussion of an

unapproved/

investigative use of

a commercial product/

device.

Educational Gap

A better understanding of the prenatal, postnatal, and surgical management of gastro-

schisis and omphalocele is needed to further improve care of affected infants.

AbstractOmphalocele and gastroschisis are the two most common congenital abdominal walldefects requiring neonatal intensive care. Historically treated as a single entity, theyrepresent two distinct pathologies with different clinical management algorithmsand associated outcomes. With improvements in prenatal diagnosis, neonatal intensivecare, and pediatric surgical practices, good long-term outcomes are possible in the ab-sence of catastrophic bowel injury or debilitating associated anomalies.

Learning Objectives After completing this article, readers should be able to:

1. Recognize that omphalocele and gastroschisis represent two distinct pathologies with

different genetic and embryologic origins.

2. Be aware that initial management requires cardiopulmonary stabilization and

protection of the eviscerated bowel or omphalocele sac.

3. Understand that small defects are often closed primarily, but definitive management

of larger defects often requires serial reduction with silo placement (gastroschisis) or

epithelialization with delayed closure (omphalocele).

4. Acknowledge that good long-term outcomes are common for both defects in the

absence of catastrophic bowel injury or significant associated anomalies.

IntroductionOmphalocele and gastroschisis are the most common congenital abdominal wall defectsrequiring neonatal intensive care. Omphalocele is a midline defect characterized by eviscer-ated abdominal contents covered by a protective sac (Fig 1). It is associated with advancedmaternal age and karyotype abnormalities. Gastroschisis, in comparison, is a defect in theabdominal wall located just lateral to the umbilicus that exposes the eviscerated abdominalcontents to the amniotic fluid (Fig 2). As a consequence, omphalocele is rarely associatedwith intestinal injury, whereas gastroschisis may be complicated by inflamed, volvulized,atretic, and/or perforated intestine. Gastroschisis is associated with young maternal age,maternal smoking, alcohol use, illicit substance abuse, and use of over-the-counter vasoac-tive medications and salicylates. Historically, omphalocele had an incidence twice that ofgastroschisis; however, the incidence of gastroschisis has more recently increased for rea-sons that are unclear. Both defects now occur at a rate of w1 to 3 per 10,000 live births.

PathogenesisOmphalocele

Omphalocele is a congenital malformation resulting from incomplete body wall foldingduring embryogenesis. The defect is most commonly located at the base of the umbilical

*Resident in Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA.†Associate Professor of Surgery, Department of Surgery, Stanford University School of Medicine, Lucile Packard Children’s Hospital,

Stanford, CA.

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stalk in the midline, with less common variants occurringin the epigastric and infraumbilical regions. The eviscer-ated contents, which include small bowel and sometimescolon and liver, are contained within a protective saccomprising peritoneum, Wharton’s jelly, and amnion.Other solid viscera are occasionally involved. Unlike

gastroschisis, omphalocele is associated with other anom-alies 50% to 70% of the time, with up to 50% of affectedinfants having significant congenital cardiac disease.

The intact sac of the omphalocele that partitions theviscera from the amniotic fluid usually protects it fromthe prolonged ileus characteristic of gastroschisis. Becauseof the broad base of the defect, strangulation is unlikely.However, a ruptured omphalocele is often complicatedby ileus, the severity of which seems to be related to thelength of exposure of the viscera to the amniotic fluid inutero. Ileocolonic volvulus is also a possibility that maynot be initially apparent.

The immediate and long-term outcomes of childrenwho have omphalocele are directly related to the severityof the associated anomalies. In addition to congenital cardiacdisease, omphalocele is frequently associated with geneticanomalies and syndromic presentations. Approximately10% of affected infants will have Beckwith-Wiedemannsyndrome (gigantism, macroglossia, omphalocele, and hy-poglycemia secondary to pancreatic hyperplasia). Otherassociations of multiple anomalies include CHARGE(coloboma, heart defects, choanal atresia, mental retarda-tion, and genitourinary and ear anomalies) and VAC-TERL (vertebral, anal, cardiac, tracheoesophageal, renal,and limb deformities).

GENETICS. Associated karyotype abnormalities arefound in w30% of infants who have omphalocele, themost common being trisomy 13, 18, and 21. Pituitaryhomeobox 2, insulin-like growth factor 2, cyclin-dependentkinase inhibitor 1C, and a polymorphism in the methyl-enetetrahydrofolate reductase gene (677C-T) have allbeen associated with omphalocele, but the exact extentto which these genes are involved in its pathogenesis re-mains uncertain.

EMBRYOLOGY. The anatomic pathology (and subse-quent clinical management) of an omphalocele is inti-mately related to the events of embryogenesis and fetaldevelopment. The third week of gestation is character-ized by the formation of the trilaminar germ disc com-posed of endoderm, mesoderm, and ectoderm. Therapid growth of the ectoderm and mesoderm (the outertwo layers) leads to ventral folding of the embryo aroundthe endoderm (the main precursor of the visceral organs).This process involves four body wall folds (cranial, caudal,and two lateral folds), which in normal developmentapproximate in the midline to form the umbilical ring.The sixth week of gestation is characterized by physio-logic herniation of the midgut through the umbilicalring, with subsequent intestinal rotation (270 degrees,

Figure 1. Omphalocele.

Figure 2. Gastroschisis.

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counterclockwise) and spontaneous reduction of the her-niated bowel by week 10 of gestation. An omphalocelearises from incomplete folding of the lateral body wall foldsand incomplete reduction of the physiologic intestinal her-niation. The umbilical stalk persists as a broad-based pro-tective sac composed of peritoneum and amnion separatedby a layer of Wharton’s jelly (mucopolysaccharides).

Variants of omphalocele occur in the epigastrium andthe infraumbilical region and are the result of incompletefolding of the cranial and caudal body wall folds, respec-tively. Epigastric omphalocele in combination with sternalcleft, ectopia cordis/cardiac defects, pericardial defects,and diaphragmatic hernia is known as the Pentalogy ofCantrell. Infraumbilical omphalocele, often associatedwith bladder or cloacal exstrophy, occurs in conjunctionwith imperforate anus and spinal defects to form the OEISassociation (omphalocele, exstrophy of the bladder, imper-forate anus, and spinal defects).

GastroschisisGastroschisis is an abdominal wall defect that almost al-ways occurs 1 to 2 cm to the right of the umbilicus. Un-like omphalocele, the eviscerated structures do not havea protective sac and are therefore in direct contact withthe amniotic fluid in utero. This contact leads to the char-acteristic edematous, foreshortened, fibrin-covered smallbowel. Gastroschisis typically occurs as an isolated mal-formation, and morbidity in the neonatal period is almostalways directly related to the extent of gastrointestinaldisease.

Approximately 10% of infants born with gastroschisiswill have a concurrent intestinal atresia or stenosis, a pro-cess likely related to in utero vascular compromise fromvolvulus or compression of the bowel at the abdominalwall. As with omphalocele, intestinal nonrotation is fre-quently present in affected individuals. Prolonged ileusthat delays enteral feeding is encountered to some extentin virtually all infants who have gastroschisis. This out-come is thought to be secondary to the effects of in uteroexposure of the bowel to amniotic fluid. Animal studieshave shown that complete amniotic fluid replacementprevents the development of characteristic bowel inflam-mation; this finding has not, however, been translated in-to clinically useful therapy.

Gastroschisis is frequently associated with intrauterinegrowth restriction, with w20% to 60% of affected infantsborn below the 10th percentile for birthweight. Thecause for this phenomenon is not well understood butis potentially related to both placental anomalies and di-rect nutritional wasting secondary to the exposed viscera.Conversely, omphalocele is not associated with

intrauterine growth restriction but rather is found in neo-nates who are often large for gestational age.

Gastroschisis is also associated with prematurity inw30% of affected individuals. This population is notimmune to the complications of prematurity and lowbirthweight. Necrotizing enterocolitis is frequently en-countered both before and after correction of the abdom-inal wall defect and can be a catastrophic complication.Similar to premature infants who do not have gastroschisis,necrotizing enterocolitis tends to occur after the initiationof enteral feeds and is more common in infants weighingless than 2500 g at birth.

GENETICS. The genetic basis for gastroschisis, as withomphalocele, is not well defined. Gastroschisis is mostoften sporadic, but there are reports of familial cases, in-cluding concordance for the defect in monozygotic twins,dizygotic twins, and distant relatives. Multiple genes havebeen implicated in the development of gastroschisis, in-cluding those encoding endothelial nitric oxide synthase,intracellular adhesion molecule 1, and atrial natriureticpeptide. Polymorphisms within these genes are associatedwith a nearly twofold increase in the odds of developinggastroschisis; this figure increases to greater than fivefoldwhen combined with maternal smoking.

EMBRYOLOGY. Unlike omphalocele, the embryologicetiology of gastroschisis is a debated topic for which anumber of theories have emerged over the last 50 years.Importantly, the association with endothelial nitric oxidesynthase and intracellular adhesion molecule 1, alongwith the significant influence of maternal smoking, lendssupport to theories of vasculogenic pathogenesis. In 1980,deVries suggested that untimely involution of the rightumbilical vein leads to apoptosis in the surrounding mes-enchyme and resorption of the body wall. This theory isfavored because it explains the right-sided preponder-ance of the defect and fits with the genetic associationsdescribed earlier. Interestingly, there are rare cases ofleft-sided gastroschisis found in the setting of left um-bilical vein resorption. Others have suggested that earlyinvolution of the vitelline artery causes body wall ischemiaand necrosis. Counterarguments to this second theory,however, note that segmental vessels from the aorta, notthe vitelline vessels, typically perfuse the abdominal wall.Other theories of pathogenesis include rupture of the um-bilical membrane before reduction of the physiologic vis-ceral herniation (essentially a ruptured omphalocele),teratogenic interference with mesenchymal differentiation,and failed fusion of the yolk sac with the umbilical stalk,leaving the yolk sac as a lead point for herniation. Definitive

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evidence is lacking in each case, and this remains an area ofboth active debate and investigation.

Differential DiagnosisPrune-belly (Eagle-Barrett) syndrome is defined as thecongenital absence of abdominal wall musculature, bilat-eral cryptorchidism, and ureteral, bladder, and urethralanomalies. It is a rare condition, with an incidence ofw1 per 50,000 live births with a strong male preponder-ance. The characteristic flaccidity and wrinkling of the ab-dominal skin is a direct result of the absent musculaturebut rarely causes functional impairment. The outcomesassociated with prune-belly syndrome are directly relatedto the severity of the genitourinary anomalies. Prune-belly syndrome is differentiated from omphalocele bycontainment of the abdominal viscera within a continuouslayer of skin and the presence of a normal umbilicus.

Umbilical hernias occur in roughly 80% of neonateswith birthweights <1200 g and in 20% of neonates withbirthweights <2500 g, and they represent incompleteclosure of the umbilical ring after separation of the um-bilical stalk. They are differentiated from other congenitalabdominal wall defects by the presence of epithelializedskin overlying the defect and the presence of an intact,but enlarged, umbilical ring. The majority of umbilicalhernias will spontaneously resolve in the first few yearsof life. Therefore, they are typically repaired before 5years of age for urgent indications (incarceration, obstruc-tion, or pain) only. A variant of an umbilical hernia, aso-called “umbilical cord hernia,” resembles a small om-phalocele and is easily repaired postnatally with reductionof the contents and ligation of the base of the cord.

ManagementPrenatal Care

Routine prenatal ultrasound often provides the initial di-agnosis of an abdominal wall defect. Ultrasound has a sen-sitivity of w60% to 75% and a specificity of w95% forboth omphalocele and gastroschisis. As is the case withultrasound in many settings, utility is affected by the tim-ing of the study and operator experience. After the inutero diagnosis of an abdominal wall defect, comprehen-sive fetal imaging, including echocardiography and mag-netic resonance imaging, should be performed to identifyany associated anomalies.

Laboratory studies have little diagnostic or prognosticvalue with the exception of maternal serum a-fetoprotein(AFP) levels. Maternal serum AFP is commonly used toscreen for chromosomal abnormalities and neural tubedefects, and is also helpful in screening for abdominal walldefects. Gastroschisis is associated with high levels of

maternal serum AFP (approximately seven to nine multi-ples of themean), whereas omphalocele typically has amoremodest elevation (approximately fourmultiples of themean).

Elevated AFP levels or positive ultrasound findingsshould lead to consideration of amniocentesis or chorionicvillus sampling. High-risk pregnancies are identified by thepresence of significant karyotype abnormalities and allowfor parental counseling and mobilization of health care re-sources. After prenatal diagnosis, referral for delivery at acenter with access to both a neonatologist and a pediatricsurgeon is an important next step in management.

The mode and timing of delivery for both omphaloceleand gastroschisis are controversial. Sonographic evidenceof fetal bowel dilation and thickened bowel wall has beensuggested as an indication for induced preterm delivery,and some authors suggest that cesarean delivery is pre-ferred in the setting of omphalocele to avoid sac rupture.There is currently no definitive evidence, however, to rec-ommend induced preterm delivery or elective cesarean de-livery for neonates who have abdominal wall defects.

Postnatal CareBoth omphalocele and gastroschisis present with varyingdegrees of severity, and the involvement of both a neona-tologist and a pediatric surgeon is mandatory to achievethe best possible outcomes. The basic principles of initialmanagement include cardiopulmonary stabilization fol-lowed by protection of the exposed viscera or omphalo-cele. An important initial consideration for neonates whohave either gastroschisis or omphalocele is thermoregula-tion because the exposed viscera predispose to hypother-mia, particularly with gastroschisis. Immediate measuresinclude protection with saline-soaked dressings and place-ment of a “bowel bag” to limit insensible fluid and heatlosses. The surgeon must then assess the viability of theexposed intestine and consider the severity of any asso-ciated anomalies while formulating a comprehensivecare plan with the neonatologists. Both the embryo-logic and pathophysiologic distinctions between om-phalocele and gastroschisis lead to differences in theoptions for definitive treatments (discussed in the fol-lowing sections).

OMPHALOCELE. Immediate management considera-tions for omphalocele include airway protection with in-tubation and mechanical ventilation if necessary, fluidresuscitation (omphalocele predisposes to increased in-sensitive fluid loss, although not as dramatically as gastro-schisis), gastric decompression, and protection of the sacwith saline-soaked dressings. After initial stabilization,efforts are directed toward identifying any associated

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anomalies. This evaluation includes a detailed physical ex-amination, karyotype analysis, echocardiography, and re-nal ultrasonography.

The definitive management of omphalocele dependson both the size of the defect and the integrity of thesac (intact or perforated). A “giant omphalocele” (basediameter >4 cm) with an intact sac is treated with dailyapplication of silver sulfadiazine to promote progressiveepithelialization (Figs 3A and 3B). A body wrap is placedand progressively tightened to facilitate reduction of theabdominal contents and to reestablish the peritoneal do-main. Elective repair of the fascial defect is performed af-ter a minimum of 6 months but typically after 2 years ofage. If the sac is ruptured, a loose silo fashioned from si-lastic mesh is secured to the edges of the defect and usedto cover the intestine. Sequential cinching of the silo inthe midline allows gradual reduction of the bowel and re-establishment of abdominal domain, after which the silois removed and a second interposition mesh is placed toachieve abdominal wall closure. It is rarely possible toachieve primary facial closure.

Small omphaloceles, which are more frequently asso-ciated with karyotype abnormalities, are either closed pri-marily or epithelialized with delayed closure. If primaryclosure is considered, the eviscerated structuresmust be re-ducible without inducing an abdominal compartmentsyndrome. This is typically defined as bladder pressure>20 mmHg or central venous pressure >4 mmHg.The presence of associated anomalies requiring more ur-gent intervention also precludes primary closure.

GASTROSCHISIS. As with omphalocele, the initial man-agement of gastroschisis begins with airway protection,fluid resuscitation, placement of an orogastric tube,and protection of the eviscerated structures with moistdressings and a protective covering (“bowel bag”). If seg-ments of necrosis or perforation are present, immediatesurgical resection is required. No attempt is made at pri-mary anastomosis in the presence of ongoing inflamma-tion, and any identified atretic segments are often leftuntouched. If the peritoneal cavity will accommodate,the eviscerated structures are reduced, stomas are createdif necessary, and the abdomen is closed. If there are bowelanomalies, reexploration and reestablishment of intestinalcontinuity are planned only after resolution of bowel in-flammation in 6 weeks’ time.

If resection is needed, it is imperative to preserve asmuch bowel length as possible to avoid long-term paren-teral nutrition dependence. This process typically requiresat least 30 cm of small bowel if the ileocecal valve is leftintact or >50 cm if the ileocecal valve is removed. The

development of short bowel syndrome is dependent ona number of factors other than bowel length, however,including gestational age, quality of remaining bowel,and the presence of the ileum for absorption of vitaminB12 and fat-soluble vitamins.

Figure 3. A giant omphalocele A. before and B. after fullepithelialization.

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If the bowel is viable at birth, the options for definitivemanagement include reduction with primary closure orserial reduction with delayed closure. When the eviscer-ated structures are reducible without causing an abdom-inal compartment syndrome or respiratory compromise,primary closure is a reasonable course of action. Delayedclosure involves placement of a preformed silo witha spring-loaded base over the eviscerated structures, withanchoring of the atraumatic spring deep to the fascial de-fect (Fig 4A). This procedure can be done either at thebedside or in the operating roombased on the stability of the infantand surgeon preference. Serial reduc-tion is then accomplished by once- ortwice-daily ligation of the silo untilthe eviscerated contents are entirelyreduced (Figs 4B and 4C).

After reduction (either primaryor delayed), the defect is typicallyrepaired by suturing the fascial de-fect and attempting a cosmetic re-construction of the skin defect andumbilicus. Sutureless closure has beenproposed as an alternative to thetraditional sutured closure and isgaining popularity, with emergingreports of decreased length of me-chanical ventilation and improvedcosmesis at the umbilicus (Figs 5A–5D). This technique involves pri-mary or staged reduction of theintestine followed by placementof a plastic-occlusive dressing overthe defect (without any attempt atsuture closure of the defect). If pri-mary reduction is achieved and a suf-ficient length of umbilical cord isintact, the cord can be used as a bi-ological bowel cover under the plas-tic dressing. With silo reduction, thecord is typically already removed, inwhich case a nonabrasive absorptivesponge such as Mepitel� (MölnlyckeHealth Care US, LLC, Norcross,GA) is placed between the plasticdressing and the bowel. The woundis then allowed to heal by secondaryintention. The umbilical ring closesby contraction, and full epithelializa-tion is achieved by 2 weeks. Thechild is typically left with a sometimes

sizable umbilical hernia, which in most cases closes by 1year of age.

Postreduction ManagementAntibiotics are continued for 48 hours after reduction orsilo placement. In the absence of other major physio-logic or anatomic anomalies, attention is focused on pro-viding adequate caloric intake and electrolyte homeostasis.Because prolonged ileus is almost always encountered,parenteral nutrition is initiated early in all cases of

Figure 4. Delayed closure is performed when the abdominal domain is insufficient forprimary reduction. A. A silo with a spring-loaded base is placed, and; B. the silo is tieddown over several days until; C. complete reduction is achieved.

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gastroschisis. Selective use of parenteral nutrition is ap-propriate for infants who have an omphalocele. Enteralfeeding is initiated as early in the postnatal period as pos-sible and can be started even while waiting for definitiveclosure of the abdominal wall defect. We initiate trophicenteral feeding as soon as gastric tube output decreasesand titrate to meet caloric requirements as tolerated. Avariation of this method, the so-called minimal enteralfeeding, has been shown to decrease the length of depen-dence on parenteral nutrition, rates of nosocomial infec-tions, and length of hospitalization. Given the frequencyof prolonged ileus in the setting of gastroschisis, the eval-uation for mechanical obstruction (ie, small bowel

contrast study) is not undertaken until the sixth weekof life followed by elective repair of any identified intes-tinal stricture or atresia.

OutcomesThe outcomes associated with omphalocele are directlyrelated to the presence of associated anomalies. Isolatedomphalocele has a mortality rate of w10%, but this fig-ure increases to nearly 60% when other anomalies arepresent. The most common complications related to theomphalocele include ileus, wound infection, and sepsis,all of which occur inw15% of affected individuals. Con-comitant cardiopulmonary disease and chromosomal

Figure 5. “Sutureless” closure is performed after complete reduction. A. An occlusive plastic dressing is applied over the defect,which is plugged using either non-adherent gauze or; B. the child’s intact umbilical cord. C. Epithelialization occurs after 7–14 daysand the child is left with an umbilical hernia. D. Most hernias close by one year of age, and an excellent cosmetic result is achieved.

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anomalies are the leading causes of death in the acutesetting.

In comparison, the outcomes associated with gastro-schisis are directly related to the severity of the gastroin-testinal disease. The overall mortality rate is w4% to 7%,and the majority of those deaths are in the setting of gas-trointestinal catastrophe (eg, extensive necrosis, multipleatresias, short bowel syndrome). The most common sur-vivable complications of gastroschisis are prolonged ileus,catheter-related infections, and sepsis, all of which occurin w15% to 30% of affected individuals.

If survival is achieved in the neonatal period, excellentlong-term outcomes are now relatively common for bothisolated omphalocele and uncomplicated gastroschisis.Childhood studies cite higher rates of learning disabilitiesin survivors of abdominal wall defects; however, adultsurvivors attain levels of education and positions of em-ployment similar to the general population. Furthermore,roughly nine of 10 adult survivors of omphalocele or gas-troschisis consider themselves to be in generally goodhealth. The most common complaints in this populationinclude abdominal scarring and intermittent abdominaldiscomfort and/or symptoms of gastroesophageal reflux.

SummaryOmphalocele and gastroschisis represent two distinctpathologies with different genetic, embryologic, and envi-ronmental components. Aggressive resuscitative measuresalong with patience in reduction and closure of the defectallow for preservation of gastrointestinal function in themajority of cases. Long-term survival with excellent func-tional outcomes is possible in the absence of catastrophicbowel injury or significant associated anomalies.

Suggested ReadingCantrell JR, Haller JA, Ravitch MM. A syndrome of congenital defects

involving the abdominal wall, sternum, diaphragm, pericardium,and heart. Surg Gynecol Obstet. 1958;107(5):602–614

Carpenter MW, Curci MR, Dibbins AW, Haddow JE. Perinatalmanagement of ventral wall defects. Obstet Gynecol. 1984;64(5):646–651

Christison-Lagay ER, Kelleher CM, Langer JC. Neonatal abdominalwall defects. Semin Fetal Neonatal Med. 2011;16(3):164–172

deVries PA. The pathogenesis of gastroschisis and omphalocele.J Pediatr Surg. 1980;15(3):245–251

Ginn-Pease ME, King DR, Tarnowski KJ, Green L, Young G,Linscheid TR. Psychosocial adjustment and physical growth inchildren with imperforate anus or abdominal wall defects.J Pediatr Surg. 1991;26(9):1129–1135

Islam S. Advances in surgery for abdominal wall defects: gastro-schisis and omphalocele. Clin Perinatol. 2012;39(2):375–386

Katz LA, Schultz RE, Semina EV, Torfs CP, Krahn KN, MurrayJC. Mutations in PITX2 may contribute to cases of omphaloceleand VATER-like syndromes. Am J Med Genet A. 2004;130A(3):277–283

Klück P, Tibboel D, van der Kamp AW, Molenaar JC. The effect offetal urine on the development of the bowel in gastroschisis.J Pediatr Surg. 1983;18(1):47–50

Koivusalo A, Lindahl H, Rintala RJ. Morbidity and quality of life inadult patients with a congenital abdominal wall defect: a ques-tionnaire survey. J Pediatr Surg. 2002;37(11):1594–1601

Lammer EJ, Iovannisci DM, TomL, Schultz K, ShawGM. Gastroschisis:a gene-environment model involving the VEGF-NOS3 pathway.Am J Med Genet C Semin Med Genet. 2008;148C(3):213–218

Lansdale N, Hill R, Gull-Zamir S, et al. Staged reduction ofgastroschisis using preformed silos: practicalities and problems.J Pediatr Surg. 2009;44(11):2126–2129

Ledbetter DJ. Congenital abdominal wall defects and reconstruc-tion in pediatric surgery: gastroschisis and omphalocele. SurgClin North Am. 2012;92(3):713–727, x

Mac Bird T, Robbins JM, Druschel C, Cleves MA, Yang S, HobbsCA; National Birth Defects Prevention Study. Demographicand environmental risk factors for gastroschisis and omphalocelein the National Birth Defects Prevention Study. J Pediatr Surg.2009;44(8):1546–1551

Moore TC, Stokes GE. Gastroschisis; report of two cases treated bya modification of the gross operation for omphalocele. Surgery.1953;33(1):112–120

Riboh J, Abrajano CT, Garber K, et al. Outcomes of suturelessgastroschisis closure. J Pediatr Surg. 2009;44(10):1947–1951

Sadler TW. The embryologic origin of ventral body wall defects.Semin Pediatr Surg. 2010;19(3):209–214

Segel SY, Marder SJ, Parry S, Macones GA. Fetal abdominal walldefects and mode of delivery: a systematic review. Obstet Gynecol.2001;98(5 pt 1):867–873

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American Board of Pediatrics Neonatal–PerinatalContent Specifications

• Know the pathogenesis, clinicalmanifestations, and associatedabnormalities of gastroschisis.

• Know the approach to management, thecomplications, and the difficulties inproviding enteral nutrition to neonateswith gastroschisis.

• Know the pathogenesis and associated anomalies associatedwith omphalocele.

• Know the approach to management, clinical manifestations,the differential diagnosis of, and the complications oftreatment of omphalocele in neonates.

• Realize the association of major congenital anomaliesinvolving the gastrointestinal tract and abdominal wall withthose involving other organs.

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NeoReviews QuizNew minimum performance level requirementsPer the 2010 revision of the American Medical Association (AMA) Physician’s Recognition Award (PRA) and credit system, a minimum performancelevel must be established on enduring material and journal-based CME activities that are certified for AMA PRA Category 1 CreditTM. In order tosuccessfully complete 2013 NeoReviews articles for AMA PRA Category 1 CreditTM, learners must demonstrate a minimum performance level of 60%or higher on this assessment, which measures achievement of the educational purpose and/or objectives of this activity.

Starting with 2012 NeoReviews, AMA PRA Category 1 CreditTM can be claimed only if 60% or more of the questions are answered correctly. If youscore less than 60% on the assessment, you will be given additional opportunities to answer questions until an overall 60% or greater score isachieved.

1. A prenatal diagnosis of gastroschisis is made for a 20-year-old mother who will deliver at your institution.Which of the following is true for the mother/fetus regarding this diagnosis?

A. Compared with omphalocele, the diagnosis of gastroschisis is much more likely to be associated with otheranomalies, with 50% having congenital heart disease.

B. The most common abdominal wall defect in gastroschisis occurs 1 to 2 cm to the left of the umbilicus.C. Gastroschisis is associated with prematurity in w30% of affected patients.D. Although there is a lack of a continuous protective sac, the intestines are usually covered by a thick coating

of Wharton’s jelly.E. Approximately one-half of infants who have gastroschisis have pseudo-gigantism and will be large for

gestational age.

2. A 30-year-old mother has a previous child who had gastroschisis. She is now pregnant again and asks aboutthe possibility of prenatal diagnosis of gastroschisis. Which of the following is true?

A. Because it is a gross abdominal wall defect, ultrasound at 18 to 20 weeks should have 100% sensitivity,although specificity for gastroschisis may be 80% to 90%.

B. Gastroschisis is associated with decreased levels of maternal serum a-fetoprotein on the prenatal screen.C. If gastroschisis is detected, the mother should opt for a cesarean delivery between 30 and 32 weeks’

gestational age.D. Maternal smoking is associated with increased risk of developing gastroschisis, particularly in the context

of polymorphisms within certain genes such as those encoding endothelial nitric oxide synthase.E. The standard of care has moved to fetal surgery at 24 weeks to repair the defect in utero to reduce

inflammation of the intestines.

3. A mother who has a known prenatal diagnosis of omphalocele in the fetus presents in active labor at 37 weeks’gestational age. Which of the following is an appropriate aspect of initial management for this mother andinfant?

A. Tocolysis should be initiated to avert delivery until 39 weeks.B. There is clear evidence that cesarean delivery will improve prognosis for both the mother and infant.C. After birth, the omphalocele should be protected with saline-soaked dressings and placement of a “bowel

bag.”D. Intubation of the infant in the delivery room should be avoided to prevent bowel distension, and blow-by

oxygen can be given if the patient is cyanotic.E. In almost all circumstances, if the patient is stable from a respiratory standpoint, the patient should be

taken to the operating room directly after delivery.

4. A male infant who has gastroschisis is born at 33 weeks’ gestational age. On initial examination, the bowelgenerally looks healthy and viable. Which of the following is an appropriate aspect of clinical management forthis infant?

A. The patient should be stabilized in the NICU for at least 1 week of antibiotics before any surgery orprocedure.

B. The patient should be taken to the operating room on the first day, have any suspicious necrotic segmentsremoved, with primary anastomoses at those segments and primary closure of the abdomen.

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C. The patient should be started on feedings first, and if not tolerated within 1 week, started on parenteralnutrition at that time.

D. Because the amniotic fluid can cause inflammation to the exposed bowel, the patient should have thebowel soaked in an antibiotic-infused solution within the “bowel bag” or silo for at least 2 days.

E. If the eviscerated structures are reducible without causing abdominal compartment syndrome orrespiratory compromise, primary closure may be a reasonable option.

5. A 35-weeks’-gestational-age female infant who has gastroschisis is now 2 weeks old and has had definitiveclosure of her defect. Which of the following is appropriate in terms of nutrition management for this infant?

A. Because the patient is now 2 weeks old and 37 weeks’ corrected age, parenteral nutrition can bediscontinued if her weight is back up to birthweight, with the goal of preventing liver disease.

B. Enteral feedings should be started at 40 weeks’ gestation or later; feedings will not be tolerated until thattime, and parenteral nutrition will supply adequate calories.

C. Trophic enteral feedings can be started when gastric output via the orogastric tube decreases.D. Before any feedings, a small-bowel contrast study should be performed to assess for patency of the

intestines.E. In most cases of gastroschisis, definitive closure leads to active bowel function, and an infant at this age

should be able to feed ad libitum without other nutrition supplementation in the next 2 to 3 days.

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DOI: 10.1542/neo.14-8-e4022013;14;e402NeoReviews 

Zachary J. Kastenberg and Sanjeev DuttaVentral Abdominal Wall Defects

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