The myth of gastroschisis

Gastroschisis prevalence patterns in 27 surveillance programs from 24 countries, International Clearinghouse for Birth Defects Surveillance and Research, 1980-2017

BACKGROUND

Gastroschisis is a serious birth defect with midgut prolapse into the amniotic cavity. The objectives of this study were to evaluate the prevalence and time trends of gastroschisis among programs in the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR), focusing on regional variations and maternal age changes in the population.

METHODS

We analyzed data on births from 1980 to 2017 from 27 ICBDSR member programs, representing 24 countries and three regions (Europe+ (includes Iran) , Latin America, North America). Cases were identified using diagnostic codes (i.e., 756.7, 756.71, or Q79.3). We excluded cases of amniotic band syndrome, limb-body wall defect, and ruptured omphalocele. Programs provided annual counts for gastroschisis cases (live births, stillbirths, and legally permitted pregnancy terminations for fetal anomalies) and source population (live births, stillbirths), by maternal age.

RESULTS

Overall, gastroschisis occurred in 1 of every 3268 births (3.06 per 10,000 births; 95% confidence intervals [CI]: 3.01, 3.11), with marked regional variation. European+ prevalence was 1.49 (95%CI: 1.44, 1.55), Latin American 3.80 (95%CI: 3.69, 3.92) and North American 4.32 (95%CI: 4.22, 4.42). A statistically significant increasing time trend was observed among six European+ , four Latin American, and four North American programs. Women <20 years of age had the highest prevalence in all programs except the Slovak Republic.

CONCLUSIONS

Gastroschisis prevalence increased over time in 61% of participating programs, and the highest increase in prevalence was observed among the youngest women. Additional inquiry will help to assess the impact of the changing maternal age proportions in the birth population on gastroschisis prevalence.

Anatomy and embryology of abdominal wall defects

Abdominal wall defects are one of the most frequently encountered human congenital anomalies. They are seen in as many as 1 in 2,000 live births with evidence to suggest that their incidence is increasing. While often discussed together abdominal wall defects consist mainly of two entities namely gastroschisis and omphalocele. There are marked differences in their theories of embryo-pathogenesis, clinical presentation/anatomy and overall outcomes. There is no clear consensus explaining the precise embryological mechanisms leading to the development of abdominal wall defects. Many clinicians and embryologists have attempted to explain the genesis of congenital abdominal wall defects because of failure of progression of various phases of normal embryonic development. This review summarizes the mechanisms involved in normal and abnormal development of the ventral abdominal wall leading to the development of gastroschisis and omphalocele.

Coexisting gastrointestinal and hepatobiliary tract anomalies in omphalocele and gastroschisis: A twenty-year experience in a single tertiary medical center

BACKGROUND

Omphalocele and gastroschisis are the two most common congenital abdominal wall defects; however, no previous study has focused on gastrointestinal and hepatobiliary tract malformations in these two conditions. This study aimed to investigate the demographic characteristics, coexisting congenital gastrointestinal and hepatobiliary tract anomalies, hospital course, and outcomes of patients with gastroschisis and omphalocele.

METHODS

This is retrospective chart review of all patients admitted to one tertiary medical center in Taiwan between January 1, 2000 and June 30, 2020 with a diagnosis of gastroschisis or omphalocele. The medical records were reviewed to obtain demographic data regarding coexisting gastrointestinal and hepatobiliary tract anomalies and outcomes.

RESULTS

Of the 51 patients included, 21 had gastroschisis and 30 had omphalocele. Gastroschisis was associated with a significantly younger maternal age and a higher incidence of small for gestational age. Of the 30 patients with omphalocele, twelve had associated gastrointestinal and hepatobiliary anomalies. Seven of the 21 patients with gastroschisis had gastrointestinal anomalies, and none had hepatobiliary anomalies. Among the omphalocele patients, three (10%) had documented malrotation, and one developed midgut volvulus. Among gastroschisis patients, four patients (19%) had malrotation, and two developed midgut volvulus. There were no statistically significant differences in postoperative complications or mortality rates between those with and without gastrointestinal/hepatobiliary tract anomalies.

CONCLUSION

The diversity of coexisting gastrointestinal and hepatobiliary tract anomalies is higher in the omphalocele than in gastroschisis. In addition, we demonstrate that patients with gastroschisis or omphalocele have a higher rate of intestinal malrotation and midgut volvulus.

The complex search for the cause of gastroschisis

BACKGROUND

To reveal the complex etiology of gastroschisis through two independent cases.

CASES

Case 1 involves gastroschisis recurrence in a consanguineous marriage, and Case 2 concerns a fetus with gastroschisis whose mother had undergone gastroplasty. Methylation array was carried out in both cases (two fetuses with gastroschisis, their two mothers, one father from the consanguineous marriage), and in 16 controls (fetuses and their respective mothers).

CONCLUSION

The two cases presented different noninherited methylation profiles.

Fetal Surgery for Gastroschisis—A Review with Emphasis on Minimally Invasive Procedures

(1) Background: The morbidity of gastroschisis is defined by exposure of unprotected intestines to the amniotic fluid leading to inflammatory damage and consecutive intestinal dysmotility, the viscero-abdominal disproportion which results in an abdomen too small to incorporate the herniated and often swollen intestine, and by associated pathologies, such as in complex gastroschisis. To prevent intestinal damage and to provide for growth of the abdominal cavity, fetal interventions such as amnio exchange, gastroschisis repair or covering have been evaluated in several animal models and human trials. This review aims to evaluate the reported techniques for the fetal treatment of gastroschisis by focusing on minimally invasive procedures. (2) Methods: We conducted a systematic database search, quality assessment and analyzed relevant articles which evaluate or describe surgical techniques for the prenatal surgical management of gastroschisis in animal models or human application. (3) Results: Of 96 identified reports, 42 eligible studies were included. Fetal interventions for gastroschisis in humans are only reported for EXIT procedures and amnio exchange. In animal models, particularly in the fetal sheep model, several techniques of open or minimally invasive repair of gastroschisis or covering the intestine have been described, with fetoscopic covering being the most encouraging. (4) Discussion: Although some promising minimally invasive techniques have been demonstrated in human application and animal models, most of them are still associated with relevant fetal morbidity and mortality and barely appear to be currently applicable in humans. Further research on specific procedures, instruments and materials is needed before any human application.

Complex gastroschisis: a new indication for fetal surgery?

Gastroschisis (GS) is a congenital abdominal wall defect, in which the bowel eviscerates from the abdominal cavity. It is a non-lethal isolated anomaly and its pathogenesis is hypothesized to occur as a result of two hits: primary rupture of the 'physiological' umbilical hernia (congenital anomaly) followed by progressive damage of the eviscerated bowel (secondary injury). The second hit is thought to be caused by a combination of mesenteric ischemia from constriction in the abdominal wall defect and prolonged amniotic fluid exposure with resultant inflammatory damage, which eventually leads to bowel dysfunction and complications. GS can be classified as either simple or complex, with the latter being complicated by a combination of intestinal atresia, stenosis, perforation, volvulus and/or necrosis. Complex GS requires multiple neonatal surgeries and is associated with significantly greater postnatal morbidity and mortality than is simple GS. The intrauterine reduction of the eviscerated bowel before irreversible damage occurs and subsequent defect closure may diminish or potentially prevent the bowel damage and other fetal and neonatal complications associated with this condition. Serial prenatal amnioexchange has been studied in cases with GS as a potential intervention but never adopted because of its unproven benefit in terms of survival and bowel and lung function. We believe that recent advances in prenatal diagnosis and fetoscopic surgery justify reconsideration of the antenatal management of complex GS under the rubric of the criteria for fetal surgery established by the International Fetal Medicine and Surgery Society (IFMSS). Herein, we discuss how conditions for fetoscopic repair of complex GS might be favorable according to the IFMSS criteria, including an established natural history, an accurate prenatal diagnosis, absence of fully effective perinatal treatment due to prolonged need for neonatal intensive care, experimental evidence for fetoscopic repair and maternal and fetal safety of fetoscopy in expert fetal centers. Finally, we propose a research agenda that will help overcome barriers to progress and provide a pathway toward clinical implementation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Is fetal magnetic resonance imaging volumetry of eventrated organs in gastroschisis predictive for surgical treatment?

BACKGROUND

Fetal MRI is increasingly used in congenital abdominal wall defects. In gastroschisis, the role of fetal MRI in surgical therapy is poorly understood. Currently, the type of repair is determined primarily by clinical presentation and institutional preference.

OBJECTIVE

To evaluate the feasibility of fetal MRI volumetry in gastroschisis treatment.

MATERIALS AND METHODS

We included 22 cases of gastroschisis in this retrospective single-center study. Routine fetal MRI scans were acquired between Jan. 1, 2006, and July 1, 2018, at gestational ages of 19-34 postmenstrual weeks. Fetal-MRI-based manual segmentation and volumetry were performed utilizing steady-state free precision and T2-weighted sequences. Acquired parameters included intraabdominal volume, eventrated organ volume and total fetal body volume, and we calculated a volume ratio between eventrated organ volume and intraabdominal volume (E/I ratio).

RESULTS

Primary closure was conducted in 13 cases and silo bag treatment with delayed closure in 9 cases. Prenatal MRI volumetry showed a significantly higher E/I ratio in patients with silo bag treatment with delayed closure (mean [M]=0.34; 95% confidence interval [CI] 0.30, 0.40) than in primary closure (M=0.23, 95% CI 0.19, 0.27; P=0.004). We propose a volume ratio cutoff value of 0.27 for predicting silo bag treatment.

CONCLUSION

Fetal MRI predicted silo bag treatment in patients with gastroschisis in 90% of the cases in our cohort and might facilitate prenatal counseling and treatment planning.

Gastroschisis: A State-of-the-Art Review

Gastroschisis, the most common type of abdominal wall defect, has seen a steady increase in its prevalence over the past several decades. It is identified, both prenatally and postnatally, by the location of the defect, most often to the right of a normally-inserted umbilical cord. It disproportionately affects young mothers, and appears to be associated with environmental factors. However, the contribution of genetic factors to the overall risk remains unknown. While approximately 10% of infants with gastroschisis have intestinal atresia, extraintestinal anomalies are rare. Prenatal ultrasound scans are useful for early diagnosis and identification of features that predict a high likelihood of associated bowel atresia. The timing and mode of delivery for mothers with fetuses with gastroschisis have been somewhat controversial, but there is no convincing evidence to support routine preterm delivery or elective cesarean section in the absence of obstetric indications. Postnatal surgical management is dictated by the condition of the bowel and the abdominal domain. The surgical options include either primary reduction and closure or staged reduction with placement of a silo followed by delayed closure. The overall prognosis for infants with gastroschisis, in terms of both survival as well as long-term outcomes, is excellent. However, the management and outcomes of a subset of infants with complex gastroschisis, especially those who develop short bowel syndrome (SBS), remains challenging. Future research should be directed towards identification of epidemiological factors contributing to its rising incidence, improvement in the management of SBS, and obstetric/fetal interventions to minimize intestinal damage.

Gastroschisis Is Associated With Placental Delayed Villous Maturation

Gastroschisis is a congenital abnormality characterized by visceral herniation through an abdominal wall defect. While the cause of gastroschisis is unknown, it has been linked to risk factors including young maternal age, smoking, and alcohol use during pregnancy. To date, the only established placental correlate is amniocyte vacuolization. Based on our clinical experience, we hypothesized that delayed villous maturation (DVM) is also associated with gastroschisis. We conducted a retrospective slide review of 23 placentas of neonates with gastroschisis. Additionally, we selected 2 control groups of placentas: 1 with a previous diagnosis of DVM and 1 with normal villous morphology. All placentas were randomized and reviewed by 2 perinatal pathologists, who were blinded to the group; DVM and amniocyte vacuolization were assessed. Gastroschisis was associated with increased placental DVM in 65.2% of cases (vs 13.6% of controls; P = .0007) and increased amniocyte vacuolization in 52.2% of cases (vs 9.1% of controls; P = .003) compared to the control group. Based on the normal and DVM groups, kappa agreement between current slide review and initial pathology diagnosis was 0.419, indicating moderate agreement. Our study shows that gastroschisis is associated with placental DVM. This association may be due to (1) a common upstream factor contributing to both gastroschisis and DVM or (2) DVM may be a consequence of the altered placental and amniotic environment in the context of gastroschisis.

Regional cluster of vanishing gastroschisis: A comparative study of antenatal and post-natal outcomes

AIM

Vanishing gastroschisis describes the in utero spontaneous closure of the periumbilical defect. It is usually associated with intestinal loss due to ischaemia, necrosis and atresia. This comparative study aims to investigate the spectrum of pathology, antenatal ultrasound characteristics and post-natal outcomes.

METHODS

Our tertiary centre provides antenatal and post-natal care of major congenital anomalies for a population of 1.6 million. Medical records were retrospectively evaluated for all cases of vanishing gastroschisis from May 2014 to May 2015. Cases of normal variant gastroschisis born during the same period were used for comparison. Maximum antenatael bowel diameter measurements were compared using the Mann-Whitney U-test.

RESULTS

Six infants with vanishing gastroschisis were born during the study period, representing 50% of all live-born gastroschisis. Antenatal ultrasound showed progressively increasing intra-abdominal bowel dilatation, with antenatal intra-abdominal bowel diameter significantly greater in vanishing, than normal, variant gastroschisis (23.2 vs. 4.1 mm, P < 0.01). The classification of vanishing gastroschisis severity comprised two type I, three type II and one type III cases. Complete midgut atresia affected three infants, leading to overall mortality of 50% for the vanishing gastroschisis group versus 0% in the normal variant group (P = 0.05).

CONCLUSION

Vanishing gastroschisis is a severe, often catastrophic variant of gastroschisis. Aetiological factors contributing to the recent high incidence of this rare complication in our population of newborns remain unknown, prompting secondary prevention strategies to salvage the midgut. We propose closer antenatal surveillance for fetuses with intra-abdominal bowel dilatation >10 mm to prompt consideration of earlier delivery to improve morbidity and mortality.

Bioinformatic Analysis of Gene Variants from Gastroschisis Recurrence Identifies Multiple Novel Pathogenetic Pathways: Implication for the Closure of the Ventral Body Wall

We investigated whether likely pathogenic variants co-segregating with gastroschisis through a family-based approach using bioinformatic analyses were implicated in body wall closure. Gene Ontology (GO)/Panther functional enrichment and protein-protein interaction analysis by String identified several biological networks of highly connected genes in UGT1A3, UGT1A4, UGT1A5, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, AOX1, NOTCH1, HIST1H2BB, RPS3, THBS1, ADCY9, and FGFR4. SVS–PhoRank identified a dominant model in OR10G4 (also as heterozygous de novo), ITIH3, PLEKHG4B, SLC9A3, ITGA2, AOX1, and ALPP, including a recessive model in UGT1A7, UGT1A6, PER2, PTPRD, and UGT1A3. A heterozygous compound model was observed in CDYL, KDM5A, RASGRP1, MYBPC2, PDE4DIP, F5, OBSCN, and UGT1A. These genes were implicated in pathogenetic pathways involving the following GO related categories: xenobiotic, regulation of metabolic process, regulation of cell adhesion, regulation of gene expression, inflammatory response, regulation of vascular development, keratinization, left-right symmetry, epigenetic, ubiquitination, and regulation of protein synthesis. Multiple background modifiers interacting with disease-relevant pathways may regulate gastroschisis susceptibility. Based in our findings and considering the plausibility of the biological pattern of mechanisms and gene network modeling, we suggest that the gastroschisis developmental process may be the consequence of several well-orchestrated biological and molecular mechanisms which could be interacting with gastroschisis predispositions within the first ten weeks of development.

An evolutionary and developmental biology approach to gastroschisis

Recent advances have now made it possible to speak of gastroschisis narrowly in morphogenetic terms invoking the Rittler-Beaudoin (R-B) model. This proceeds from the appreciation of gastroschisis as a congenital intestinal herniation (without cover or liver) within the primordial umbilical ring, mostly to the right side of a normally formed umbilical cord. Presently, it is unresolved whether this visceral prolapse represents failure of ring closure before return of the physiological hernia into the abdomen or rupture of the delicate amniotic/peritoneal membrane at the ring's edge to the right of the cord. Animal observations and experiments will be required to address this question effectively. If gastroschisis is, in fact, a primary malformation with the primordial umbilical ring as the developmental field involved, then homology implies potential gastroschisis in all amniotes with corresponding nourishment from yolk sac (aka omphalomesenteric) vessels going into the embryo and excretory products out via the ancient umbilical connection. It also implies homology of corresponding morphogenetic signal transduction cascades. We review the history of gastroschisis, its presumed pathogenesis, and the developmental biology of the amniotic umbilical ring from this perspective. Therefore, based on the animal and human evidence to date, we propose that gastroschisis is a primary midline malformation that involves the umbilical canal from amniotic to peritoneal space and its primordial umbilical ring, either through nonclosure or rupture of the membrane covering the area, mostly to the right, between the cord and the edge of the ring.

Insights into the etiology and embryology of gastroschisis

The development of gastroschisis has long remained an area of interest and controversy. Successive theories about its pathogenesis are herein reviewed and discussed. Two historical assumptions, that omphalocele results from a persistent umbilical hernia, and that gastroschisis does not involve the umbilical cord, are dismissed. Therefore, one can envision gastroschisis for what it is, i.e. a ruptured physiological hernia. The causal agents for this intrauterine accident to occur are yet to be determined. Further bowel damage and complications can be explained by the mesenteric insult.

Understanding gastroschisis and its clinical management: where are we?

Gastroschisis is the commonest developmental defect of the anterior abdominal wall in both developed and developing countries. The past 30 years have seen transformational improvements in outcome due to advances in neonatal intensive care and enhanced integration between the disciplines of maternal fetal medicine, neonatology and pediatric surgery. A review of gastroschisis, which emphasizes its epidemiology, multidisciplinary care strategies and contemporary outcomes is timely. Areas covered: This review discusses the current state of knowledge related to prevalence and causation, and postulated embryopathologic mechanisms contributing to the development of gastroschisis. Using relevant, current literature with an emphasis on high level evidence where it exists, we review modern techniques of prenatal diagnosis, pre and postnatal risk stratification, preferred timing and method of delivery, options for abdominal wall closure, nutritional management, and short and long term clinical and neurodevelopmental follow-up. Expert commentary: This section explores controversies in contemporary management which contribute to practice and cost variation and discusses the benefits of novel nutritional therapies and care standardization that target unnecessary practice variation and improve overall cost-effectiveness of gastroschisis care. The commentary concludes with a review of fertile areas of gastroschisis research, which represent opportunities for knowledge synthesis and further outcome improvement.

Gastroschisis: A Review of Management and Outcomes

We performed an evidence-based review of the obstetrical management of gastroschisis. Gastroschisis is an abdominal wall defect, which has increased in frequency in recent decades. There is variation of prevalence by ethnicity and several known maternal risk factors. Herniated intestinal loops lacking a covering membrane can be identified with prenatal ultrasonography, and maternal serum α-fetoprotein level is commonly elevated. Because of the increased risk for growth restriction, amniotic fluid abnormalities, and fetal demise, antenatal testing is generally recommended. While many studies have aimed to identify antenatal predictors of neonatal outcome, accurate prognosis remains challenging. Delivery by 37 weeks appears reasonable, with cesarean delivery reserved for obstetric indications. Postnatal surgical management includes primary surgical closure, staged reduction with silo, or sutureless umbilical closure. Overall prognosis is good with low long-term morbidity in the majority of cases, but approximately 15% of cases are very complex with complicated hospital course, extensive intestinal loss, and early childhood death.

Management of gastroschisis

PURPOSE OF REVIEW

The diagnosis and treatment of gastroschisis spans the perinatal disciplines of maternal fetal medicine, neonatology, and pediatric surgery. Since gastroschisis is one of the commonest and costliest structural birth defects treated in neonatal ICUs, a comprehensive review of its epidemiology, prenatal diagnosis, postnatal treatment, and short and long-term outcomes is both timely and relevant.

RECENT FINDINGS

The incidence of gastroschisis has increased dramatically over the past 20 years, leading to a renewed interest in causation. The widespread availability of maternal screening and ultrasound results in very high rates of prenatal diagnosis, which enables evaluation of the optimal timing and mode of delivery. The preferred method of surgical closure continues to be an issue of debate among pediatric surgeons, whereas postsurgical treatment seeks to expedite the initiation and progression of enteral feeding and minimize complications. A small subset of babies with complex gastroschisis leading to intestinal failure benefit from the knowledge and expertise of dedicated interdisciplinary teams, which seek to bring novel therapies and improved clinical outcomes.

SUMMARY

The opportunities to increase the knowledge of causation, and identify best practices leading to improved outcomes, drive the ongoing need for collaborative clinical research in gastroschisis.

A genome-wide association study of copy number variations with umbilical hernia in swine

Umbilical hernia (UH) is one of the most common congenital defects in pigs, leading to considerable economic loss and serious animal welfare problems. To test whether copy number variations (CNVs) contribute to pig UH, we performed a case-control genome-wide CNV association study on 905 pigs from the Duroc, Landrace and Yorkshire breeds using the Porcine SNP60 BeadChip and penncnv algorithm. We first constructed a genomic map comprising 6193 CNVs that pertain to 737 CNV regions. Then, we identified eight CNVs significantly associated with the risk for UH in the three pig breeds. Six of seven significantly associated CNVs were validated using quantitative real-time PCR. Notably, a rare CNV (CNV14:13030843-13059455) encompassing the NUGGC gene was strongly associated with UH (permutation-corrected P = 0.0015) in Duroc pigs. This CNV occurred exclusively in seven Duroc UH-affected individuals. SNPs surrounding the CNV did not show association signals, indicating that rare CNVs may play an important role in complex pig diseases such as UH. The NUGGC gene has been implicated in human omphalocele and inguinal hernia. Our finding supports that CNVs, including the NUGGC CNV, contribute to the pathogenesis of pig UH.

When Closure Fails: What the Radiologist Needs to Know About the Embryology, Anatomy, and Prenatal Imaging of Ventral Body Wall Defects

Ventral body wall defects (VBWDs) are one of the main categories of human congenital malformations, representing a wide and heterogeneous group of defects sharing a common feature, that is, herniation of one or more viscera through a defect in the anterior body wall. Gastroschisis and omphalocele are the 2 most common congenital VBWDs. Other uncommon anomalies include ectopia cordis and pentalogy of Cantrell, limb-body wall complex, and bladder and cloacal exstrophy. Although VBWDs are associated with multiple abnormalities with distinct embryological origins and that may affect virtually any system organs, at least in relation to anterior body wall defects, they are thought (except for omphalocele) to share a common embryologic mechanism, that is, a failure involving the lateral body wall folds responsible for closing the thoracic, abdominal, and pelvic portions of the ventral body wall during the fourth week of development. Additionally, many of the principles of diagnosis and management are similar for these conditions. Fetal ultrasound (US) in prenatal care allows the diagnosis of most of such defects with subsequent opportunities for parental counseling and optimal perinatal management. Fetal magnetic resonance imaging may be an adjunct to US, providing global and detailed anatomical information, assessing the extent of defects, and also helping to confirm the diagnosis in equivocal cases. Prenatal imaging features of VBWDs may be complex and challenging, often requiring from the radiologist a high level of suspicion and familiarity with the imaging patterns. Because an appropriate management is dependent on an accurate diagnosis and assessment of defects, radiologists should be able to recognize and distinguish between the different VBWDs and their associated anomalies. In this article, we review the relevant embryology of VBWDs to facilitate understanding of the pathologic anatomy and diagnostic imaging approach. Features will be illustrated with prenatal US and magnetic resonance imaging and correlated with postnatal and clinical imaging.

Left-sided gastroschisis with caecal agenesis: A rare case report

Gastroschisis is a congenital anomaly characterised by a defect in the anterior abdominal wall through which the intestinal contents freely protrude. Defect is located almost always to right of umbilicus. To our knowledge very few cases of left-sided gastroschisis have occurred and presented in literature. We report case of left-sided gastroschisis with caecal agenesis, short gut, and malrotation of intestine.

Abdominal wall defects: prenatal diagnosis, newborn management, and long-term outcomes

Omphalocele and gastroschisis represent the most frequent congenital abdominal wall defects a pediatric surgeon is called to treat. There has been an increased reported incidence in the past 10 years mainly due to the diffuse use of prenatal ultrasound. The early detection of these malformations, and related associated anomalies, allows a multidisciplinary counseling and planning of delivery in a center equipped with high-risk pregnancy assistance, pediatric surgery, and neonatology. At present times, closure of defects, even in multiple stages, is always possible as well as management of most of cardiac-, urinary-, and gastrointestinal-associated malformations. The progress, herein discussed, in the care of newborns with abdominal wall defects assures most of them survive and reach adulthood. Some aspects of transition of medical care will also be considered, including fertility and cosmesis.

A vascular and thrombotic model of gastroschisis

A binary vascular/thrombotic pathogenesis for gastroschisis, a form of congenital bowel herniation, is proposed, where normal right umbilical vein involution creates a possible site for thrombosis adjacent to the umbilical ring. If thrombosis occurs, it weakens the area, explaining overwhelmingly right-sided lesions. The model arises from the existence of two groups of risk factors with different maternal age associations. Older mothers show a greater association with vascular factors (although this may actually represent a lack of any significant maternal age effect), consistent with associations of gastroschisis with congenital heart lesions and with amyoplasia. Alternatively, other predispositions, and especially decreased maternal age, the greatest known risk factor, associate with factors raising maternal estrogen, with evidence that estrogen in turn acts here as a predisposition to thrombosis. Absorption of thrombotic by-products from the amniotic fluid can explain the unusual amniocyte inclusions that are common with gastroschisis, while a role for estrogens suggests a connection between rising gastroschisis prevalence and increasing environmental contamination with estrogen disruptors. This model explains a variety of structural and epidemiological findings, and suggests that stratification of data based on binary effects may clarify associated risks and mechanisms. The model also shows that what is often referred to as vascular disruption may actually reflect alternative or additional factors instead, including thrombosis as a primary mechanism.

Gastroschisis with ceco-appendicular agenesis: a novel presentation

Gastroschisis is associated with intestinal atresia and malrotation. A few cases have been reported of appendicular agenesis associated with gastroschisis. No previous case has been reported of cecal agenesis with gastroschisis in the literature. As cecal agenesis is a very rare anomaly, its concomitant presentation with gastroschisis is extremely rare. We report a case of gastroschisis associated with ceco-appendicular agenesis. The possible embryological explanation for the presentation is discussed.

Histology of a paraumbilical band in a neonate with gastroschisis

We report a case of gastroschisis in which a paraumbilical band was found at the right margin of the abdominal wall defect and extended into the antimesenteric side of the small intestine. The band consisted of 2 thin cords. Microscopically, 1 band showed a fibrous tissue, and the other 1 revealed a unique vascular structure resembling the vitelline artery and vein, suggesting that the paraumbilical band represents a remnant of the yolk stalk that failed to be incorporated into the umbilical stalk. The origin of the paraumbilical band and an associated pathogenetic hypothesis of gastroschisis are discussed.

Are abdominal wall defects and external genitalia anomalies randomly expressed in some families?

Familial cases of isolated abdominal wall defects with variable expressivity in more than one generation have rarely been observed. We report four affected individuals within a small three-generation family with either variable non-syndromic abdominal wall defects or external genital anomalies. We discuss the possible transmission of non-syndromic abdominal wall defects. It could be hypothesized that similar developmental defects may result in anomalies like hypospadias in males or developmental anomalies of the labia minora or labia majora in females.

Neonatal abdominal wall defects

Gastroschisis and omphalocele are the two most common congenital abdominal wall defects. Both are frequently detected prenatally due to routine maternal serum screening and fetal ultrasound. Prenatal diagnosis may influence timing, mode and location of delivery. Prognosis for gastroschisis is primarily determined by the degree of bowel injury, whereas prognosis for omphalocele is related to the number and severity of associated anomalies. The surgical management of both conditions consists of closure of the abdominal wall defect, while minimizing the risk of injury to the abdominal viscera either through direct trauma or due to increased intra-abdominal pressure. Options include primary closure or a variety of staged approaches. Long-term outcome is favorable in most cases; however, significant associated anomalies (in the case of omphalocele) or intestinal dysfunction (in the case of gastroschisis) may result in morbidity and mortality.

Development of gastroschisis as seen by magnetic resonance imaging

OBJECTIVES

To describe the magnetic resonance imaging (MRI) morphology and fetal development of gastroschisis.

METHODS

Twenty-seven fetal MRI studies of 24 fetuses (mean gestational age 30 (range, 21-38) weeks), with gastroschisis were retrospectively analyzed. The extra- and intra-abdominal positions of the abdominal organs were assessed on T1- and T2-weighted and steady-state free-precession sequences with emphasis on the intra-abdominal findings.

RESULTS

Third-trimester fetuses (n = 16) showed a uniform morphology: the extracorporeal bowel included jejunum, ileum and colon except for parts of the sigmoid and the rectum. Intra-abdominally the stomach was in contact with the left-sided urinary bladder in 15 of these. Second-trimester fetuses (n = 8) differed with respect to the amount of intra-abdominal bowel and had longer sections of the colon and jejunum intra-abdominally. Intrauterine follow-up (n = 3) demonstrated exteriorization of these bowel segments. Three third-trimester fetuses with gastroschisis complicated by small bowel obstruction, in addition to the dilated small bowel loops, had variable lengths of intra-abdominal colon.

CONCLUSIONS

Fetal development of gastroschisis is a dynamic process lasting until birth. The typical morphology of gastroschisis changes from the second to the third trimester, since intra-abdominal bowel becomes eventrated by the end of the second trimester. This process of eventration is stopped in cases of intestinal stenosis/atresia caused by narrowing of the abdominal wall defect, resulting in different lengths of intra-abdominal bowel. The time when this occurs may correlate with the amount of viable bowel in cases of intestinal atresia. The concept presented here explains the findings in closing gastroschisis.

Pathogenic implications of remnant vitelline structures in gastroschisis

PURPOSE

The pathogenesis of gastroschisis is unknown. It may be helpful in understanding its pathogenesis to know the structural relationships among umbilical components including umbilical vessels, urachus, and vitelline structures, and thus, the authors investigated the remnants of vitelline structures in a series of cases of gastroschisis.

METHODS

Medical records of 41 cases with gastroschisis treated in our institute from 1979 to 2009 were retrospectively reviewed.

RESULTS

Paraumbilical bands, possible remnants of vitelline structures, were observed in 4 cases (9.8%). All 4 bands were attached to the skin edge of the abdominal defect without incorporation into the umbilical cord. The band ended at the mesentery in 3 cases and at the antimesenteric site of the ileum in the remaining case. Histologic findings showed fibrous tissues in all cases. One was possibly associated with the development of colonic atresia. Another was noticed after silo reduction when herniated bowels became strangulated by the band. The other 2 cases were uncomplicated.

CONCLUSIONS

Our findings may support the recently proposed hypothesis that the developmental failure of the yolk sac and related vitelline structures to merge with or to be incorporated into the umbilical stalk might be associated with the pathogenesis of the abdominal wall defect in gastroschisis. Paraumbilical bands derived from vitelline structures may possibly cause intestinal ischemia prenatally or postnatally.

The embryologic origin of ventral body wall defects

Ventral body wall defects include ectopia cordis, bladder exstrophy, and the abdominal wall malformations gastroschisis and omphalocele. The etiology of ectopia cordis, gastroschisis, and bladder exstrophy is not known, but they may be linked to abnormalities in the lateral body wall folds responsible for closing the thoracic, abdominal, and pelvic portions of the ventral body wall. These folds form in the fourth week (postfertilization) of development as a combination of the parietal layer of lateral plate mesoderm and overlying ectoderm and must move ventrally to meet in the midline. There are differential rates of cell proliferation in the folds and asymmetries in their movement that may be involved in teratogenic effects of toxic factors. Also, the fusion process between the folds is complex, involving cell-to-cell adhesion, cell migration, and cell reorganization and all of these phenomena may be targets for disruption, leading to malformations. In this regard, closure of the ventral body wall is likened to neural tube closure and involves similar processes. It also encompasses a similar time frame during development, such that most neural tube and ventral body wall defects have their origins during the fourth week of development. Omphalocele is a separate entity whose etiology is known. This defect is attributed to a failure of gut loops to return to the body cavity after their normal physiological herniation into the umbilical cord from the 6th to 10th week of development. Thus, the origin of this defect is completely different from that of the ventral body wall malformations.

Is there epidemiologic evidence to support vascular disruption as a pathogenesis of gastroschisis?

Gastroschisis is a congenital defect of the abdominal wall that occurs most commonly in the offspring of young women. The defect is often hypothesized to result from vascular disruption in the early embryo. We measured the associations between maternal vasoactive exposures in pregnancy, as possible markers of vascular disruption, and gastroschisis risk, using data collected as part of the National Birth Defects Prevention Study. Study participants included mothers of births from October 1997 to December 2003 in 10 states. The mothers of 514 gastroschisis cases were matched by age at delivery and state to 3,277 non-malformed controls and compared for periconceptional smoking and use of vasoconstrictors, non-steroidal anti-inflammatory drugs (NSAIDs), and vasodilators. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CI) were estimated from conditional logistic regression. Case mothers were more likely than control mothers to smoke (OR = 1.5, 95% CI = 1.2-1.9) and report use of non-aspirin NSAIDs (1.4, 1.1-1.7) and anti-hypertensive vasodilators (2.6, 0.9-8.0), but not vasoconstrictive decongestants (1.0, 0.7-1.4). Cigarette smoking had little effect on gastroschisis risk in mothers <25 years of age, but the OR was 3.0 (1.8-5.0) for those >or=25 years. Likewise, ORs were greatest in the older women for use of non-aspirin NSAIDs (1.6, 1.0-2.6) and bronchodilators (3.0, 1.8-5.0). These findings suggest that, overall, vasoactive risk factors play a minor role in the etiology of gastroschisis, and do not support the vascular disruption hypothesis. However, the observation that increased ORs for some vasoactive exposures were confined to older women raises the question of whether inherent maternal factors might influence risk.

Antenatal diagnosis and perinatal care of anterior abdominal wall defects

Improvements in anaesthetic care and postoperative management over the last two decades have significantly improved survival of neonates with ventral abdominal wall defects, from a dismal 47% in 1971, to 96% for both gastroschisis and isolated omphalocele in two recent series. This increased survival has generally been attributed to result from improvements in the pre and postoperative management of these fragile neonates. Specifically, the routine use of total parenteral nutrition, and staged repairs for cases with severe “viscero-abdominal disproportion” have been implicated in a decreased incidence of sepsis, morbidity and mortality. In addition, an appreciation of the wide spectrum of anomalies uniquely associated with gastroschisis and omphalocele have helped improve survival, as each has unique pathophysiologic features that have prognostic implications for the fetus before, during and after delivery.

Gastroschisis and omphalocele: treatments and long-term outcomes

Between February 1994 and April 2004, we treated 40 children with gastroschisis and 26 children with omphalocele. We recorded the course of pregnancy, pre- and post-natal complications, delivery, operation, post-operative therapy, and long-term outcomes. Additionally, we conducted follow-up examinations of 37 of these 66 children (56%). We analysed their abdominal musculature, development, cosmetic result and quality of life. The median duration of follow-up was 6.3 years (range 1-10). In 35/40 children (88%) with gastroschisis and in 18/26 children (69%) with omphalocele, there had been prenatal diagnosis. The average maternal age of 23.9 years in the gastroschisis group was lower than in the omphalocele group (29.9 years). Delivery was by caesarean section in 93% of the gastroschisis group and 65% of the omphalocele group. Outcomes following vaginal delivery were no worse than those after caesarean section. Further, congenital abnormalities were shown in 28% of gastroschisis cases, and were limited to the gastrointestinal tract. Of the omphalocele cases 81% showed further abnormalities. Direct closure of the abdominal wall defect was possible in 31/40 (78%) of the gastroschisis cases and 15/26 (58%) of the omphalocele cases. Mortality in gastroschisis was nil; two children with omphalocele died (8%). Outcomes were better after primary closure than in stepwise reconstruction. Follow-up showed good results in all categories. Developmental delays were rapidly made up after treatment, and 75% of the children had no gastrointestinal problems, or suffered from these rarely. Almost all the children were of normal weight and height, and physical and intellectual development were delayed in only one third of the children. The surgical scar was rated as good or very good in about 80% of the cases. Except for those with severe defects, the children had good ratings for quality of life. Improvements in short-term results of gastroschisis and omphalocele treatment can be attributed to recent developments in prenatal diagnosis and the advancements of centralised perinatal care. Our long-term results clearly demonstrate that initial gastrointestinal problems and developmental delays were made up during the first two years of life. Prenatal counselling can now be more optimistic.

Development of gastroschisis: review of hypotheses, a novel hypothesis, and implications for research

Gastroschisis, a ventral body wall defect, is a continuing challenge and concern to researchers, clinicians, and epidemiologists seeking to identify its cause(s) and pathogenesis. Concern has been renewed in recent years because, unlike most other birth defects, rates of gastroschisis are reportedly increasing in many developed and developing countries. No tenable explanation or specific causes have been identified for this trend. Rates of gastroschisis are particularly high among pregnancies of very young women. Such an intriguing association, not observed to this degree with other birth defects, may afford clues to the defect's cause. Understanding the causes of gastroschisis may provide insight to the defect's origin. In pursuing such causal studies, it would be helpful to understand the embryogenesis of gastroschisis. To date, four main embryologic hypotheses have been proposed: (1) Failure of mesoderm to form in the body wall; (2) Rupture of the amnion around the umbilical ring with subsequent herniation of bowel; (3) Abnormal involution of the right umbilical vein leading to weakening of the body wall and gut herniation; and (4) Disruption of the right vitelline (yolk sac) artery with subsequent body wall damage and gut herniation. Although based on embryological phenomena, these hypotheses do not provide an adequate explanation for how gastroschisis would occur. Therefore, we propose an alternative hypothesis, based on well described embryonic events. Specifically, we propose that abnormal folding of the body wall results in a ventral body wall defect through which the gut herniates, leading to the clinical presentation of gastroschisis. This hypothesis potentially explains the origin of gastroschisis as well as that of other developmental defects of the ventral wall.

Gastroschisis associated with cleft lip and palate

Gastroschisis is a common congenital abdominal wall defect. Rarely, it is associated with extraabdominal midline congenital anomalies. Oral clefts are the commonest craniofacial congenital midline defects. They can be associated with other midline defects like omphalocele. We believe these are the first 3 case reports of gastroschisis and cleft palate occurring in the same patient.

Omphalocele associated with gastroschisis defect covered with skin

Omphalocele and gastroschisis are distinct malformations in many aspects. Anatomical and pathologic findings in both conditions are usually typical and very frequent. Unusual clinical presentations of some cases may contribute to clearing up questions about the embryological origins of gastroschisis and omphalocele. We describe a rare case of omphalocele associated with gastroschisis defect covered with skin.

Prenatal management of gastroschisis: the place of the amnioexchange procedure

Gastroschisis is a malformation of the anterior abdominal wall that consists of a right paraumbilical defect with bowel loops bathed in the amniotic fluid. The survival rate is now greater than 90% and the prognosis relies mainly on morbidity attributable to bowel dysfunction. Recent research has examined gastrointestinal waste present in amniotic fluid that induces bowel toxicity and an inflammatory process. The amnioexchange procedure (changing the amniotic fluid regularly) involves a new therapeutic approach: reducing bowel injuries in the fetuses. This article shows that there is an inflammatory reaction in human gastroschisis and in the authors' model, and that the clinical and biological data plead for the practice of amnioexchange in human beings. A randomized, controlled study is now needed.

Unusual Presentations of Gastroschisis

Gastroschisis is a defect of the ventral abdominal wall nearly always located to the right of the umbilicus. A relatively low incidence of associated anomalies exists with the most common being nonduodenal intestinal atresia occurring in 10 per cent of patients. Although multiple hypotheses have been proposed the pathogenesis of gastroschisis is unproven and controversial. Herein we describe four infants with rare presentations of gastroschisis: one infant with true left-sided gastroschisis and three infants with unusual patterns of intestinal atresia. At present there is a female preponderance of left-sided gastroschisis as reported in the world literature (five female:two male). These cases illustrate the anatomic spectrum of gastroschisis as well as support intrauterine spontaneous closure of the abdominal wall defect as an etiology for midgut atresia.

Complications of intrauterine intervention for treatment of fetal obstructive uropathy

The intrauterine surgical placement of vesicoamniotic shunts in the treatment of fetal obstructive uropathy associated with prune-belly syndrome to avoid such complications as renal damage and oligohydramnios remains controversial. We present a case of an infant born with prune-belly syndrome at 33 weeks and 5 days of estimated gestational age to a mother of two by vaginal delivery after a pregnancy complicated by fetal obstructive uropathy with attempted intrauterine intervention. After sonographic and laboratory diagnostic and prognostic evaluations, an intrauterine procedure was performed in which a vesicoamniotic shunt was placed under ultrasound guidance. Complications included dislodgment of the initial shunt, with a failed subsequent attempt at placement, oligohydramnios, preterm labor and delivery, and traumatic gastroschisis through the surgical abdominal wall defect. His hospital stay was further complicated by chronic renal insufficiency, prematurity, respiratory distress, bowel malrotation, an episode of gram-negative sepsis with Enterobacter cloacae, signs of liver failure, an exploratory laparotomy for severe enterocolitis, and orchiopexy for bilateral undescended testes. At present, it is unclear whether vesicoamniotic shunt placement can provide any significant improvement in the morbidity or mortality for patients with prune-belly syndrome. A large, prospective, randomized trial is needed to determine its efficacy.