Prenatal and postnatal management of omphalocele

PRENATAL DIAGNOSISPrenat Diagn 2008; 28: 626–632.Published online in Wiley InterScience(www.interscience.wiley.com) DOI: 10.1002/pd.2008

REVIEW

Prenatal and postnatal management of omphalocele

Stephanie Mann1,2*, Thane A. Blinman2,3 and R. Douglas Wilson1,2

1Center for Fetal Diagnosis and Treatment, Children’s Hospital of Philadelphia, 34th Street and Civic Center Boulevard,Philadelphia, PA, USA2University of Pennsylvania School of Medicine, 34th Street and Civic Center Boulevard, Philadelphia, PA, USA3Division of General, Thoracic, and Fetal Surgery, Children’s Hospital of Philadelphia, 34th Street and Civic Center Boulevard,Philadelphia, PA, USA

Omphalocele is one of the most common abdominal wall defects seen in the prenatal period. Once thisdiagnosis is confirmed, it is important to check the fetal karyotype and thoroughly assess the fetus for othermalformations. Prenatal management involves serial assessment of fetal growth and prenatal testing to ensurefetal well-being. Closure of the abdominal wall and replacement of organs into the abdominal cavity canbe done directly if the omphalocele is small or in a staged manner if the omphalocele is large. Successfuloutcomes for these neonates can be optimized with a multidisciplinary team approach to prenatal and postnatalmanagement. Copyright 2008 John Wiley & Sons, Ltd.

KEY WORDS: omphalocele; abdominal wall defect; umbilical hernia

INTRODUCTION

Omphalocele is one of the most common anteriorabdominal wall defects seen in the prenatal period. Theoverall incidence of omphalocele is approximately 1 in3000 live births (Paidas et al., 1994; Axt et al., 1999;Barisic et al., 2001). However, it has been noted inseveral epidemiologic reviews that the incidence of thisabdominal wall defect varies by ethnicity and geographicorigin (Tan et al., 1996; Salihu et al., 2003, 2004).

Omphalocele is a midline defect in the anteriorabdominal wall that results in herniation of abdominalcontents into a membrane-covered sac. The contentsof the sac, which is composed of an inner layer ofperitoneum and an outer layer of amnion, can includesolely intestine or can also contain liver and stomach.Omphaloceles are classified as small (bowel, stomach,and no liver), giant (bowel, stomach, and liver) andruptured (Kamata et al., 1996; Tsakayannis et al., 1996;Biard et al., 2004).

Beginning at the 6th postconception week, rapidelongation of the gut and increased liver size resultin crowding of the intraabdominal space. As a result,intestinal loops are pushed out of the abdominal cavityinto the proximal umbilical ring. During the 10th week,the intestine returns to the abdominal cavity and theprocess is completed by the 12th week. Persistence ofintestine or the presence of other abdominal viscerain the umbilical cord results in an omphalocele. Theembryogenesis of this defect remains to be elucidated;however, it is thought that there is a failure of abdominal

*Correspondence to: Stephanie Mann, Children’s Hospital ofPhiladelphia, 34th Street and Civic Center Boulevard, WoodCenter 5131, Philadelphia, PA 19104, USA.E-mail: [email protected]

wall closure at the umbilical ring that results froma defect in lateral folding in the embryo (Vermeij-Keers et al., 1996). Hence, omphalocele is part of aspectrum of body wall anomalies that include Pentalogyof Cantrell, which is associated with an abnormality incranial folding and bladder/cloacal exstrophy, which isdue to a defect in caudal infolding (Ghidini et al., 1988).

Although omphaloceles can occur as isolated anoma-lies, up to 70% of these defects can be associated withother malformations and can be attributed to a singlegene disorder, chromosomal abnormalities, or geneticsyndromes (Boyd et al., 1998; Stoll et al., 2001). Asso-ciated malformations range in severity as well as num-ber. The most common accompanying malformationinvolves the heart, as up to 50% of fetuses with omphalo-celes will have cardiac defects that include muscularventricular septal defects, atrial septal defects, or coarc-tation of the aorta (Gibbin et al., 2003). A recent reviewof malformations associated with omphalocele suggeststhat there is a correlation between defect size and spe-cific malformations; omphaloceles that contain liver andother viscera are more likely to have accompanyingcardiac, renal, and limb anomalies. In contrast, smalleromphaloceles that contain intestine only are more likelyto have coexisting gastrointestinal (GI) anomalies (i.e.intestinal atresias and duplication cysts and central ner-vous system (CNS) malformations (i.e. absence of thecorpus callosum or hydrocephalus) (Groves et al., 2006).

Single gene mutations have been suggested as apotential etiology for some omphaloceles associatedwith multiple anomalies. Specifically, mutations in theFLNA gene have been implicated in the otopalatodig-ital syndrome spectrum disorders, an X-linked groupof conditions that are characterized by abnormalities inthe axial and appendicular skeleton and are associatedwith extraskeletal malformations such as omphalocele

Copyright 2008 John Wiley & Sons, Ltd. Received: 11 July 2007Revised: 21 December 2007

Accepted: 9 March 2008

PRENATAL AND POSTNATAL MANAGEMENT OF OMPHALOCELE 627

(Robertson et al., 2003; Robertson, 2007). Omphaloce-les can also occur as part of a syndrome, the most com-mon of which is Beckwith–Wiedemann, a syndrome thatis marked by macroglossia, organomegaly, and hypo-glycemia. Another association is with the Pentalogy ofCantrell, and the OEIS (omphalocele, exstrophy, imper-forate anus, and spinal defects) complex in which exstro-phy can involve the bladder or cloaca (Martinez-Friaset al., 2001; Vasudevan et al., 2006). Associated chro-mosomal disorders are found in 30–40% of omphaloce-les and include trisomy 13, 18, 21, Turner’s syndrome,and triploidy (Lakasing et al., 2006). The risk of achromosomal abnormality varies with maternal age atdiagnosis, contents of the omphalocele and complexityof associated anomalies (Getachew et al., 1992; Groveset al., 2006). Aneuploidy is more likely to be foundin the smaller omphaloceles that contain bowel only(Nyberg et al., 1989; Benacerraf et al., 1990).

The precise etiology of omphalocele has yet to bedetermined; however, certain risk factors are known tobe associated with this abdominal wall defect. Althoughmaternal age greater than 35 is a risk factor for someof the trisomies associated with omphalocele, mater-nal age per se does not appear to be an independentrisk factor for omphalocele (Tan et al., 1996; Stollet al., 2001). However, a recent study suggests thatyounger paternal age (<25 years) may be a risk fac-tor (Yang et al., 2006). The association between theuse of assisted reproductive technology (ART) and con-genital malformations has been demonstrated in sev-eral large epidemiologic reviews (Allen et al., 2006;Zhu et al., 2006); however, the specific association withomphalocele has not been confirmed (Hansen et al.,2002; Kallen and Finnstrom, 2005). However, there isevidence to suggest that the genomic imprinting disorderBeckwith–Wiedemann Syndrome, one of the commonomphalocele-associated conditions, is increased in off-spring of women who conceived after ART (Gosdenet al., 2003; Maher et al., 2003). As with other congeni-tal anomalies, the role of periconceptional vitamin use isbeing investigated as a therapy for preventing omphalo-cele. Though far from conclusive, both epidemiologicdata (Botto et al., 2002; Botto et al., 2004) and resultsfrom molecular genetic studies (Rauch et al., 2000) sug-gest that regular use of periconceptional multivitaminsmay reduce the incidence of nonsyndromic omphalocele.

PRENATAL MANAGEMENT

Prenatal screening by maternal serum testing and ultra-sound in the second trimester allows identification ofthe majority of omphaloceles. An elevation in mater-nal serum alphafetoprotein (MSAFP) can be a markerof an omphalocele. However, the variable sensitivity ofMSAFP precludes using this marker as a screening testfor omphalocele (Palomaki et al., 1988).

As a result of technological advancements with ultra-sound, the prenatal diagnosis of omphalocele has signifi-cantly improved during the past 30 years with ultrasounddiagnosis of this abdominal wall defect being confirmedas early as 10–14 weeks (Snijders et al., 1995; van

Zalen-Sprock et al., 1997). Recently, it has been sug-gested that the fetal nuchal translucency (NT) ultrasoundexamination used to detect fetuses at risk for aneuploidyor cardiac anomalies may also aid in the early diagno-sis of a structural anomaly such as omphalocele (Soukaet al., 2006; Weiner et al., 2007).

Migration of intestinal loops into the umbilical cordnormally occurs between 8 and 12 weeks of gestation;the intestinal loops return into the abdominal cavity in allnormally developing fetuses after 12 completed weeksof gestation (van Zalen-Sprock et al., 1997). Therefore,before 12 weeks it is difficult to differentiate betweena small omphalocele with only bowel herniation versusnormal physiological midgut herniation. If the intestineremains herniated into the umbilical cord after 11 weeks,the presence of bowel loops in the umbilical cord isno longer physiologic. However, protrusion of the liverand/or stomach is abnormal in any situation; therefore,if these findings are seen on a first-trimester ultrasoundthe diagnosis of omphalocele is likely.

Once confirmed, ultrasound evaluation should iden-tify which viscera are present in the sac, the relation-ship between the umbilical cord and the abdominalwall defect, and the presence or absence of ascites(Figure 1). As discussed above, the increased associ-ation with other congenital malformations and geneticsyndromes such as Pentalogy of Cantrell, amniotic bandsyndrome, OEIS syndrome (omphalocele, exstrophy ofthe bladder, imperforate anus, spinal defects) and Beck-with–Wiedemann syndrome necessitates a meticulousassessment of all fetal organs. Since as many as 50% offetuses with an omphalocele can have a congenital heartdefect, a detailed fetal echocardiogram is recommended(Tulloh et al., 1994; Gibbin et al., 2003). In addition tothe increased occurrence of congenital heart disease, thecardiac axis can also be abnormal in these fetuses, asthe physiologic herniation of the midgut occurs at thesame time as the developing heart undergoes verticaland horizontal rotation (Boulton et al., 2006).

Another imaging modality that may be useful fordelineating the aberrant anatomy in fetuses with an

Figure 1—Ultrasound image of a giant omphalocele containing liverand bowel. Stomach is intraabdominal

Copyright 2008 John Wiley & Sons, Ltd. Prenat Diagn 2008; 28: 626–632.DOI: 10.1002/pd

628 S. MANN ET AL.

omphalocele is ultrafast magnetic resonance imaging(MRI). Although not necessary for making the diagnosisof omphalocele, MRI may be useful for viewing anatom-ical details where visualization is limited by maternalbody habitus or amniotic fluid volume (Pumberger et al.,2003). Other potential applications include volumetriccalculations of lung volume (Cannie et al., 2006) orexteriorized abdominal contents (Takada et al., 2006)that may be useful in prenatal counseling and in deliveryplanning.

A karyotype is recommended because of the highincidence of chromosomal abnormalities associated withomphaloceles. Serial ultrasounds are recommended toassess growth and amniotic fluid volume as thesefetuses are at increased risk of fetal growth restrictionand polyhydramnios. Beginning at 30–32 weeks, closeprenatal surveillance that includes weekly nonstresstesting and biophysical profiles is recommended tomonitor fetal well-being as fetuses with omphaloceles,especially those in which there are other congenitalanomalies are at increased risk for intrauterine death(Hughes et al., 1989; Tucci and Bard, 1990).

INTRAPARTUM MANAGEMENT

Ideally, delivery should occur at a tertiary care centerwith the requisite neonatal and surgical support staffavailable to manage these neonates. Although it is clearthat there is no benefit to delivery prior to 37 weeksfor fetuses with omphalocele, the mode of deliveryfor these fetuses remains controversial. Retrospectivereviews examining fetal outcome with respect to modeof delivery have demonstrated no benefit to cesareandelivery (Sipes et al., 1990; Segel et al., 2001; Antebyand Yagel, 2003). However, these studies did not stratifyoutcome by size of the omphalocele. Owing to thepotential intrapartum risk of dystocia, sac rupture, andtrauma to abdominal viscera, delivery of fetuses withgiant omphaloceles should be by cesarean section.Since labor per se does negatively impact neonataloutcome and there are no studies that show a benefitto cesarean delivery, fetuses with small omphalocelescan be delivered vaginally (Lewis et al., 1990).

POSTNATAL MANAGEMENT

Newborn

Special care must be exercised immediately at deliveryto avoid damage to the sac and its fragile contents.Rupture of the sac increases the risk of infection andcan lead to intestinal or hepatic trauma, but worse,destroys options for delayed closure strategies. Theumbilicus should be divided with a generous stumpsince, especially in smaller omphaloceles, abdominalcontents may project into the cord more distally thanappreciated.

Stabilization of the infant is the immediate con-cern upon delivery of a newborn with an omphalo-cele. Depending on the type and severity of associated

defects, pulmonary or cardiac compromise may requireimmediate intubation and ventilatory support. Peripheralintravenous (and, if required, arterial) access should beplaced immediately, but no attempt should be made touse the umbilical vessels for access. An oro- or naso-gastric sump tube is placed to suction to keep the bow-els decompressed until stable. With large omphaloceles,fluid and heat loss are accelerated, and the omphalocelesac should be covered and stabilized with gauze. Somepractitioners have the mistaken idea that the omphalo-cele should be kept very moist, and wrap the babieswith saline-soaked guaze. This practice can only speedhypothermia. Better practice is loose coverage of thesac with Xeroform or other moist, nonadherent dress-ing, followed by a mildly compressive gauze wrap thattravels around the omphalocele and also has some mul-tiple wraps around the abdomen in order to stabilize thesac and contents. Some clinicians add a layer of plas-tic wrap (such as Saran-Wrap) to diminish evaporativefluid losses. However constructed, what is most impor-tant is that the wrap does not distort the sac, be too tightat the base, or restrict ventilation. Once stabilized, thebaby can be transported to the neonatal intensive careunit (NICU) for surgical evaluation and definitive care.

Preliminaries to repair

There is little urgency to the closure of an omphalo-cele; as with congenital diaphragmatic hernia, delayallows cardiopulmonary stabilization, cataloguing ofassociated defects, and formation of a safe surgicalplan. Early pulmonary compromise from associated pul-monary hypoplasia or other defects may necessitate useof oscillator ventilation, nitric oxide, or even ECMO.Cardiac defects are likely; therefore, an early, repeatechocardiogram allows proactive management. Childrenwith Beckwith–Wiedemann syndrome require vigilantmanagement of glucose. If karyotyping has not beendone prenatally, it should be considered since confirma-tion of Trisomy 13 or 18 will alter the clinical strategy.

Surgical priorities

The goals of omphalocele repair are (1) return of theviscera to the abdominal cavity and (2) closure ofboth fascia and skin. Omphalocele, like gastroschisis,usually produces a drastically diminished abdominaldomain, and forceful reduction of viscera into this smallspace may produce abdominal compartment syndrome(ACS). In ACS, high intraabdominal pressure causesrespiratory competition (high peak pressures, and risingCO2) and diminished blood flow to viscera and kidneys(oliguria, and acidosis), as well as reduced venousreturn (hypotension). The resultant hypercarbia, acidosis,oliguria, and hypotension may spawn a positive feedbackcycle, rapidly worsening unless abdominal pressure issurgically released. Surgeons have devised a number ofstrategies to avoid this problem and still achieve a soundclosure. The surgeon chooses according to the size of thedefect relative to the child, the volume of viscera thatmust be reduced, and the physiologic context producedby the child’s comorbidities.



Surgical closure techniques for omphalocele haveproliferated since the Gross technique reported in 1948(Gross, 1948). Gross mobilized and closed only theskin over the defect, preserving the sac beneath, butmaking no attempt to reduce the viscera into theabdominal cavity. Later, the resulting large ventralhernia would be closed at a second stage. Althoughsurvival was improved, this technique did little toincrease the intraabdominal space, the viscera remainlargely outside the abdominal cavity, in a skin-coveredsac, leaving final closure a problem. Since then, surgeonshave devised a number of techniques that produce betterresults and can be selected as indicated.

Direct closure

For small (<5 cm defect in a full term infant) omphalo-celes (including ‘hernia of the cord’), direct closure isthe best method. While these defects are the easiest tomanage surgically, they can be the most difficult medicalpatients: risk and severity of comorbidities (especiallychromosomal defects) do not correlate with size of thedefect.

Closure of these defects is straightforward. The sacis carefully excised, taking care to ligate the umbilicalvessels. Skin flaps are raised along the border, expos-ing the remaining fascia. Although variably displaced,the usual fascial layers and rectus and oblique musclesare still present. The fascia is usually closed vertically,reducing the viscera, and leaving the baby with narrow-ing at the waist that loosens as the baby grows. Somesurgeons will manually stretch the oblique muscles andfascia before approximating the midline. During closureof the fascia, communication between the anesthesiolo-gist and surgeon is essential to ensure that ACS is notcreated. If the pressure is too high, the surgeon musttemporize, and has several options:

• Temporary bridging of the fascia with Gore-tex orother mesh that can be removed and the fasciaclosed after the child has grown. This method mayhave a higher infection risk because of the long-term placement of a foreign object beneath thin,relatively poorly perfused flaps (Pampaloni et al.,1998; Sakellaris et al., 2002).

• Bridging of the fascia with Alloderm, Surgisys orsimilar ‘biocompatible’ product (Saxena and Willital,2002) that will incorporate into the fascia and not beremoved (Alaish and Strauch, 2006). This method hasnot been reported with large series, and the infectionand hernia risk is undefined. Similarly, Bawazir hasreported success with absorbable mesh (polyglycan)(Bawazir et al., 2003).

• Temporary closure of the skin only, with return to theoperating room and repair of the ventral hernia later.This method is essentially the Gross technique, andmay be more useful as a backup strategy than as aprimary method. This is an especially poor methodfor small defects with a large amount of unreducedviscera since the small defect can trap the visceraoutside the fascia.

• Some form of transposition of the abdominal muscula-ture, either by lateral division of the external oblique,or by creating flaps from the internal fascia of rec-tus adominus that are closed in the midline (Zaccaraet al., 2003).

• Conversion to a staged technique, such as placinga silo of polypropylene (with an inner, nonadherentlayer) (Ozbey, 2005) or silastic mesh (see below).

Various combinations and modifications of these basicstrategies may be used depending on the patient’sspecific circumstances and the surgeon’s experience.During closure, monitoring of bladder pressure maybe useful, with one group advocating the keeping ofbladder pressure below 20 mmHg to avoid pressurerelated postoperative complications (Lacey et al., 1993).

Staged reduction and closure

Larger omphaloceles that have either a very largeabdominal defect or a large amount of viscera protrudingthrough a smaller defect cannot be closed primarily. Inthese cases, the surgeon applies some type of temporarycoverage that includes some form of pressure (gravityand compression) that slowly and gradually drive theviscera back into the abdomen as edema diminishes, thebabies lose body water, and the abdominal wall stretchesand grows.

The oldest variation of this method that is still usedtoday was described by Schuster (1967). The Schusterrepair consists of sewing sheets of Teflon or Silasticmesh to the rectus sheath and gradually tightening theclosure of the two sheets over around 7–10 days untilthe midline fascia can be closed primarily. This meshdwells beneath the abdominal skin, which is reopenedwith each tightening procedure every 2–3 days. The sacis typically left intact.

Similarly, Silastic sheeting can be sewn to the fasciaaround the edges of the defect in such a manner asto create a ‘silo’ containing the viscera. The silo issuspended above the baby allowing gravity to pull theviscera back into the abdominal cavity. Many surgeonsalso place ties or sutures every 48 h in order to compressthe silo. Similarly, the silo may be compressed withbandages. Once the viscera are nearly fully reduced, aprimary repair can be completed.

‘Paint and wait’

Some omphalocele patients are too unstable for anysurgical intervention. For example, a 2-kg 32-weekEGA-premature neonate with pulmonary hypoplasia, apatent ductus arteriosus (PDA), and a large omphalocelecontaining most of the abdominal viscera will nottolerate even the moderate pressures required for stagedreduction. In this and similar cases, the safest courseis ‘paint and wait’. Here, the sac is coated with anantimicrobial agent that allows the sac to toughen intoan eschar. As the sac contracts and the baby grows,the viscera are very slowly returned to the abdominalcavity. Much later, the large ventral hernia can beclosed primarily or with a biocompatible membrane


630 S. MANN ET AL.

as describe above. This method is a poor choice foromphaloceles with a ‘mushroom’ shape; for example,where large amounts of viscera ‘mushroom’ abovea relatively narrow abdominal wall defect, since theviscera may become trapped outside the cavity, as seenwith the Gross procedure.

A number of agents have been used with thismethod. Classically, the sac would be painted with Mer-curochrome (Mebromine), a strong antiseptic and scle-rosant. In the USA, the FDA-banned Mercurochromealong with other mercury containing agents althoughthe risk of toxicity was reported to be miniscule, andno adverse reactions were seen. Others have used beta-dine solution, which is effective, but there are reportedcases of induced hypothyroidism attributed to absorptionof iodine (Cosman et al., 1988). Silver nitrate solutionwas a plausible choice, but its disadvantages (producesindelible stains on most objects it contacts; requires fre-quent reapplication; can leach electrolytes) have effec-tively barred its use. Silver sulfadiazine (Silvadene) iscurrently the most widely used agent since it has broad-spectrum activity, little toxicity, and needs only dailyapplication. Others have experimented with other silver-impregnated burn dressings, but data are limited.

Other adjuncts

Other methods of expanding the abdominal domainhave been tried. Historically, pneumoperitoneum wasused by Ravitch after a Gross procedure in order togently stretch the abdominal cavity and facilitate delayedclosure of the ventral hernia (Ravitch, 1963). In thistechnique, air is intermittently instilled via a stopcockand catheter directly into the peritoneal cavity, butproblems such as infection, compartment syndrome,air embolism, subcutaneous emphysema, etc. precludedgeneral adoption. Others have used implanted tissueexpanders with better success (Foglia et al., 2006). TheVAC suction wound closure device has also been used,with reported good results (Kilbride et al., 2006).

Surgical management of comorbidities

In patients with small omphaloceles and without majorcomorbidities, care after closure may be straightforward:diet is advanced and ventilators are weaned accordingto standard clinical endpoints; however, this is not theusual case. Meanwhile, those with giant omphalocelesare likely to require any number of interventions to man-age cardiac, pulmonary, and other surgical problems.Surgical treatment of cardiac disease is well beyond thescope of this article, but a number of other problemsmay require a surgeon’s attention.

Abdominal wall problems may surface. Soon afterclosure, for example, patients may manifest indirectinguinal hernias, and these can become disturbinglylarge. Incarceration with strangulation is rare if the inter-nal ring is widely dilated, but incarceration and evenstrangulation can occur. The mere presence of a hernia,however, is not a mandate for an early repair. The her-nias may be acting as a ‘pop-off’ for abdominal domain,and forced reduction and repair could exacerbate any

ongoing ventilatory competition. Furthermore, the per-sistently elevated intraabdominal pressure and relativelypoor tissue strength combine to make a low tension,robust closure unlikely; therefore, recurrence risk of her-niation is high. The more prudent course is to allowpatients to resolve their pulmonary problems to a largeextent (see below) and to grow. Close observation ofthe hernias until the child has better pulmonary reserveand tissue integrity is probably a safer strategy, even ifthe delay until repair lasts until 2 years of age or older.Then, simple high ligation may not be adequate to closethe very dilated internal ring. Furthermore, these patientsmay have pantaloon hernias (combined direct and indi-rect defects). In either case, ligation of the sac usuallyneeds to be combined with a floor repair.

Meanwhile, ventral hernias may appear. Recurrentventral hernias may surface at any time depending on themethod of closure, the tension on the original closure,whether mesh was left permanently, and whether infec-tions occurred in the wound. In some cases, there areolder children in whom attempts were made to close theabdomen with polypropolene mesh, and some of thesechildren now have hernias and enterocutaneous fistulas.These difficult problems require extensive dissection ofthe abdominal wall for removal of the mesh and stagedplastic surgery for closure.

The same elevated intraabdominal pressure and atten-uated tissue that produces abdominal wall herniasalso acts at the hiatus, and symptomatic gastroe-sophageal reflux is common (Wang et al., 1998). Evenwithout overt hiatal hernia, gastroesophageal reflux(GER) or GER-symptoms may manifest from increasedintraabominal pressure, delayed gastric emptying frommalrotation (which otherwise very rarely requires cor-rection by Ladd’s procedure), or slowed transit times.While the small bowel is generally less affected inomphalocele than gastroschisis, both abdominal walldefects are notorious for producing patients slow totolerate full feeds. Whatever the reason for feedingintolerance, placement of central access for parenteralnutritional support is routine. Much later in the course,patients may require Nissen fundoplasty. While biocom-patible mesh or muscular translocation type closures canmake reoperation challenging, it is not true that previ-ous omphalocele closure is an absolute contraindicationfor laparoscopic Nissen. Alternatively, some GER relief(if less than total control) may be gained by transpylorictube feeds by ND, NJ, or GJ tubes, or even transthoracicfundoplasty (Golladay and Wagner, 1990). Obviously,ND tubes are the simplest to deploy, especially earlyin the course. In any case, good control of reflux alongwith adequate enteral nutrition is essential to improvingpulmonary dysfunction.

Other surgical problems may also manifest. Smallbowel atresia is far less common than in gastroschisis,but can explain bowel that fails to ‘open’ after repair.Adhesive small bowel obstruction can develop anytimeafter closure, and the risk is higher in babies closed withmesh, in babies who develop necrotizing enterocolitis(NEC), and in babies who require ventriculoperitoneal(VP) shunts. Every child with omphalocele also hasmalrotation, and remains at some risk of volvulus, but



most surgeons do not routinely perform a Ladd’s proce-dure during repair. Any of these conditions can producebilious emesis, and differentiating among bowel obstruc-tion, bowel dysfunction, and volvulus requires clinicalvigilance. (Rescorla et al., Surgery, 1990.108.710–714.)

Although common, the exact incidence of pulmonarydisease in omphalocele is not known, in part perhapsbecause the exact nature of these babies’ problems is asyet ill described. While pulmonary hypoplasia (accom-panied by varying severity of pulmonary hypertension)is certainly seen (Biard et al., 2004), many babies withomphalocele also display a pattern of dysfunction dis-tinct from other pulmonary hypoplasia (PHP)-associateddiseases such as congenital diaphragmatic hernia. In par-ticular, babies with giant omphalocele (GO) frequentlyrequire unusual levels of PEEP, and months or evenyears of positive pressure support and tracheostomy.In addition to hypoplasia, there is an appearance ofbronchomalasia or similar obstructive pathophysiologythat seems amenable to PEEP, and makes them highlysensitive to ‘spells’ of breath-holding, desaturation, andbradycardia with agitation. An alternative explanation isthat the hypoplasia demands maximum alveolar recruit-ment to avoid sensations of air-hunger, and some aspectof the abdominal wall defect or closure contributes tochronic alveolar derecruitement and V/Q mismatch. Thisexplanation could explain the GO babies who do wellwith APRV. Whatever the explanation, the pulmonarydysfunction keeps GO babies in the NICU for months,and requires careful titration of ventilatory support.

OUTCOMES

Overall, survival rates for fetuses diagnosed with anomphalocele are highest if the fetal karyotype is normaland there are no associated anomalies (Boyd et al., 1998;Heider et al., 2004; Lakasing et al., 2006). The presenceof additional malformations adversely affects perina-tal mortality as fetuses with an omphalocele have anincreased risk of in utero death and immediate neonataldeath (Hughes et al., 1989; Tucci and Bard, 1990). Sev-eral studies have investigated the impact of defect sizeon outcome and found no relationship between defectsize and fetal or neonatal outcome (Hughes et al., 1989).The impact of liver in the omphalocele is difficult todiscern as results from studies are conflicting. However,in the euploid fetus with an isolated omphalocele, liverpresence does not appear to impact outcome (Tucci andBard, 1990; Heider et al., 2004). The one caveat is thatmost of the studies that have looked at liver position lackthe appropriate power to make definitive conclusionsabout the effect of liver position on neonatal outcome.

Biard et al. specifically reviewed outcomes in fetuseswith giant omphaloceles (Biard et al., 2004). There is a20% risk of fetal demise in this group, a finding that issimilar to the other groups of omphaloceles. Althoughthe survival rate is much higher in neonates with GOswho do not have associated malformations, the majorityof these neonates will have some degree of prolongedrespiratory insufficiency. The degree of postnatal res-piratory dysfunction is the major prognostic factor for

those infants with GOs who do not have associatedlife threatening malformations and (Tsakayannis et al.,1996) has been attributed to a smaller lung area and nar-row chest width that is hypothesized to be a sequelumof aberrant thoracic cage development in this group.

SUMMARY

Omphalocele is an abdominal wall defect that can bediagnosed in the prenatal period. Though the associatedmorbidity and mortality is high, outcomes for fetuseswith this congenital anomaly can be optimized by amultidisciplinary team that includes genetics, perinatal-ogists, pediatric surgeons, and neonatalogists.

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Prenatal and postnatal management of omphalocele