Impact of the volume of the myelomeningocele sac on imaging, prenatal neurosurgery and motor outcomes: a retrospective cohort study.

To investigate the association of the myelomeningocele (MMC) volume with prenatal and postnatal motor function (MF) in cases who underwent a prenatal repair. Retrospective cohort study (11/2011 to 03/2019) of 63 patients who underwent a prenatal MMC repair (37 fetoscopic, 26 open-hysterotomy). At referral, measurements of the volume of MMC was performed based on ultrasound scans. A large MMC was defined as greater than the optimal volume threshold (ROC analysis) for the prediction of intact MF at referral (2.7 cc). Prenatal or postnatal intact motor function (S1) was defined as the observation of plantar flexion of the ankle based on ultrasound scan or postnatal examination. 23/63 participants presented a large MMC. Large MMC lesions was associated with an increased risk of having clubfeet by 9.5 times (CI%95[2.1-41.8], p < 0.01), and reduces the chances of having an intact MF at referral by 0.19 times (CI%95[0.1-0.6], p < 0.01). At birth, a large MMC reduces the chance of having an intact MF by 0.09 times (CI%95[0.01-0.49], p < 0.01), and increases the risk of having clubfeet by 3.7 times (CI%95[0.8-18.3], p = 0.11). A lower proportion of intact MF and a higher proportion of clubfeet pre- or postnatally were observed in cases with a large MMC sac who underwent a prenatal repair.Trial registration: Clinicaltrials.gov NCT02230072 and NCT03794011 registered on September 3rd, 2014 and January 4th, 2019.

Cilia, ciliopathies and hedgehog-related forebrain developmental disorders.

Development of the forebrain critically depends on the Sonic Hedgehog (Shh) signaling pathway, as illustrated in humans by the frequent perturbation of this pathway in holoprosencephaly, a condition defined as a defect in the formation of midline structures of the forebrain and face. The Shh pathway requires functional primary cilia, microtubule-based organelles present on virtually every cell and acting as cellular antennae to receive and transduce diverse chemical, mechanical or light signals. The dysfunction of cilia in humans leads to inherited diseases called ciliopathies, which often affect many organs and show diverse manifestations including forebrain malformations for the most severe forms. The purpose of this review is to provide the reader with a framework to understand the developmental origin of the forebrain defects observed in severe ciliopathies with respect to perturbations of the Shh pathway. We propose that many of these defects can be interpreted as an imbalance in the ratio of activator to repressor forms of the Gli transcription factors, which are effectors of the Shh pathway. We also discuss the complexity of ciliopathies and their relationships with forebrain disorders such as holoprosencephaly or malformations of cortical development, and emphasize the need for a closer examination of forebrain defects in ciliopathies, not only through the lens of animal models but also taking advantage of the increasing potential of the research on human tissues and organoids.

In Utero Restoration of Hindbrain Herniation in Fetal Myelomeningocele as Part of Prenatal Regenerative Therapy Program at Mayo Clinic.

OBJECTIVE: To assess our initial experience with prenatal restoration of hindbrain herniation following in utero repair of myelomeningocele (MMC). PATIENTS AND METHODS: Three consecutive patients with prenatally diagnosed MMC (between January 1, 2018 and September 30, 2018) were managed with open in utero surgery. As per institutional review board approval and following a protocol designed at the Mayo Clinic Maternal & Fetal Center, fetal intervention was offered between 19 0/7 and 25 6/7 weeks of gestation. Prenatal improvement of hindbrain herniation was the declared restorative end point. Obstetrical and perinatal outcomes were also assessed. RESULTS: Diagnosis of MMC was confirmed upon referral between 20 and 21 weeks' gestation by using fetal ultrasound and magnetic resonance imaging. In all cases reported here, the spinal defect was lumbosacral with evidence of hindbrain herniation. Open in utero MMC repair was performed between 24 and 25 weeks' gestation with no notable perioperative complications. Postprocedure fetal magnetic resonance imaging performed 6 weeks after in utero repair documented improvement of hindbrain herniation. Deliveries were at 37 weeks by cesarean section without complications. Most recent postnatal follow-ups were unremarkable at both 11 months (baby 1) and 3 months of age (baby 2), with mild ventriculomegaly. Antenatal and postnatal follow-up of baby 3 at 1 month of age was also unremarkable. CONCLUSION: Our study highlights the prenatal restoration of hindbrain herniation following in utero MMC repair in all cases presented here as an example of a prenatal regenerative therapy program in our institution.

Like a hole in the head: Development, evolutionary implications and diseases of the cranial foramina.

Cranial foramina are holes in the skull through which nerves and blood vessels pass to reach both deep and superficial tissues. They are often overlooked in the literature; however they are complex structures that form within the developing cranial bones during embryogenesis and then remain open throughout life, despite the bone surrounding them undergoing constant remodelling. They are invaluable in assigning phylogeny in the fossil record and their size has been used, by some, to imply function of the nerve and/or blood vessel that they contained. Despite this, there are very few studies investigating the development or normal function of the cranial foramina. In this review, we will discuss the development of the cranial foramina and their subsequent maintenance, highlighting key gaps in the knowledge. We consider whether functional interpretations can be made from fossil material given a lack of knowledge regarding their contents and maintenance. Finally, we examine the significant role of malformation of foramina in congenital diseases such as craniosynostosis.

Complex malformations involving the fetal body wall - definition and classification issues.

OBJECTIVE: The objective of the study is to analyse the sonographic features, cytogenetic results and pregnancy outcomes in complex malformations involving the body wall in a large cohort of fetuses with regard to different definitions proposed in the literature. METHOD: A retrospective study on 96 fetuses with complex malformations comprising ventral wall, craniofacial structures, limbs and umbilical cord that were evaluated between 1997 and 2015. RESULTS: The most common sonographic finding was an extensive ventral wall defect (95.8%; 92/96) comprising liver (94.6%; 87/92), intestine (82.6%; 76/92), heart (17.4%; 16/92) and bladder (8.7%; 8/92). Acrania and encephalocoele were observed in 24 and 9 fetuses (25.0%, 24/96; 9.4%, 9/96), respectively. Limb anomalies were present in 54 fetuses (56.3%; 54/96). Rudimentary or absent umbilical cord was observed in 62 fetuses (64.6%; 62/96). In 79 fetuses, there were additional multiple structural anomalies detected prenatally. None of the currently used definitions encompasses all possible phenotypes of body wall defects present in our cohort. Chromosomal aberrations were seen in 8 out of 60 cases with conclusive cytogenetic result (13.3%, 8/60). CONCLUSION: Chromosomal anomalies are common, and karyotyping should be offered. There is a need for a more rigorous classification of complex malformations in order to better understand the underlying pathophysiology. © 2017 John Wiley & Sons, Ltd.

Management strategy of umbilical artery aneurysm complicated by cardiac anomaly: case study and literature review.

OBJECTIVE: Key considerations for managing an umbilical artery aneurysm (UAA) are a timely termination and the prevention of rupture of the UAA during delivery. Herein, we propose a treatment strategy based on our experience of UAA complicated by a fetal cardiac anomaly. CASE: A case of UAA was referred to our hospital at 23 weeks of gestation. The UAA increased its size to 6 cm. The blood reservoir within the UAA was presumed to be equivalent to the circulating blood volume of the fetus. At 28 weeks, small echogenic components suspected to be hematomas appeared in the umbilical vein, and the umbilical interstitial substance became edematous. An improvement in the fetus' condition could not be expected unless the UAA size was smaller. Thus, a cesarean delivery was performed at 30 weeks during which the UAA ruptured. The baby was anemic, disseminated intravascular coagulation (DIC) and later died. CONCLUSION: We present an assessment of a large blood reservoir within an UAA that may indicate the likelihood of high-output cardiac failure of the fetus. Either a classical cesarean section or a transverse uterine fundal incision should be performed when the UAA size is greater than 5 cm to prevent rupture of the UAA.

Fetal syringomyelia.

We explored the prevalence of syringomyelia in a series of 113 cases of fetal dysraphism and hindbrain crowding, of gestational age ranging from 17.5 to 34 weeks with the vast majority less than 26 weeks gestational age. We found syringomyelia in 13 cases of Chiari II malformations, 5 cases of Omphalocele/Exostrophy/Imperforate anus/Spinal abnormality (OEIS), 2 cases of Meckel Gruber syndrome and in a single pair of pyopagus conjoined twins. Secondary injury was not uncommon, with vernicomyelia in Chiari malformations, infarct like histology, or old hemorrhage in 8 cases of syringomyelia. Vernicomyelia did not occur in the absence of syrinx formation. The syringes extended from the sites of dysraphism, in ascending or descending patterns. The syringes were usually in a major proportion anatomically distinct from a dilated or denuded central canal and tended to be dorsal and paramedian or median. We suggest that fetal syringomyelia in Chiari II malformation and other dysraphic states is often established prior to midgestation, has contributions from the primary malformation as well as from secondary in utero injury and is anatomically and pathophysiologically distinct from post natal syringomyelia secondary to hindbrain crowding.

Midline craniofacial malformations with a lipomatous cephalocele are associated with insufficient closure of the neural tube in the tuft mouse.

BACKGROUND: Genetic variations affecting neural tube closure along the head result in malformations to the face and brain, posing a significant impact on health care costs and the quality of life. METHODS: We have established a mouse line from a mutation that arose spontaneously in our wild-type colony that we called tuft. Tuft mice have heritable midline craniofacial defects featuring an anterior lipomatous cephalocele. RESULTS: Whole-mount skeletal stains indicated that affected newborns had a broader interfrontal suture where the cephalocele emerged between the frontal bones. Mice with a cephalocele positioned near the rostrum also presented craniofacial malformations such as ocular hypertelorism and midfacial cleft of the nose. Gross and histological examination revealed that the lipomatous cephalocele originated as a fluid filled cyst no earlier than E14.5 while embryos with a midfacial cleft was evident during craniofacial development at E11.5. Histological sections of embryos with a midfacial cleft revealed the cephalic neuroectoderm remained proximal or fused to the frontonasal ectoderm about the closure site of the anterior neuropore, indicating a defect to neural tube closure. We found the neural folds along the rostrum of E9 to E10.5 embryos curled inward and failed to close as well as embryos with exencephaly and anencephaly at later stages. Whole-mount in situ hybridization of anterior markers Fgf8 and Sonic hedgehog indicated closure of the rostral site was compromised in severe cases. CONCLUSION: We present a model demonstrating how anterior cranial cephaloceles are generated following a defect to neural tube closure and relevance to subsequent craniofacial morphogenesis in the tuft mouse.

The Meckel syndrome protein meckelin (TMEM67) is a key regulator of cilia function but is not required for tissue planar polarity.

Meckel syndrome (MKS) is a lethal disorder associated with renal cystic disease, encephalocele, ductal plate malformation and polydactyly. MKS is genetically heterogeneous and part of a growing list of syndromes called ciliopathies, disorders resulting from defective cilia. TMEM67 mutation (MKS3) is a major cause of MKS and the related ciliopathy Joubert syndrome, although the complete etiology of the disease is not well understood. To further investigate MKS3, we analyzed phenotypes in the Tmem67 null mouse (bpck) and in zebrafish tmem67 morphants. Phenotypes similar to those in human MKS and other ciliopathy models were observed, with additional eye, skeletal and inner ear abnormalities characterized in the bpck mouse. The observed disorganized stereociliary bundles in the bpck inner ear and the convergent extension defects in zebrafish morphants are similar to those found in planar cell polarity (PCP) mutants, a pathway suggested to be defective in ciliopathies. However, analysis of classical vertebrate PCP readouts in the bpck mouse and ciliary organization analysis in tmem67 morphants did not support a global loss of planar polarity. Canonical Wnt signaling was upregulated in cyst linings and isolated fibroblasts from the bpck mouse, but was unchanged in the retina and cochlea tissue, suggesting that increased Wnt signaling may only be linked to MKS3 phenotypes associated with elevated proliferation. Together, these data suggest that defective cilia loading, but not a global loss of ciliogenesis, basal body docking or PCP signaling leads to dysfunctional cilia in MKS3 tissues.

Encephalocystocele - uncommon diagnosis in prenatal medicine.

Encephalocystocele is a developmental malformation characterized by brain herniation accompanied with extracranial cystic protrusion of the ventricular system. This nosological unit is often overlooked and insufficiently classified merely as encephalocele. Herein, two exceptionally clear cases of the parieto-occipital cranioschisis with encephalocystocele and congenital hydrocephalus of the lateral ventricles are documented with 2-dimensional/3-dimensional sonographic images and the corresponding MRI findings. In both cases, prenatal diagnosis was confirmed by autopsy.

Fetal surgery for myelomeningocele: trials and tribulations. Isabella Forshall Lecture.

The rationale for in utero repair of myelomeningocele (MMC) in the context of pathologic observations, animal models, and outcomes from the initial experience with human fetal MMC repair is presented. This has now culminated in a randomized trial, Management of Myelomeningocele Study, the findings of which are listed. The story is focused on the milestone contributions of members of the Center for Fetal Diagnosis and Treatment at the Children's Hospital of Philadelphia on the road to successful fetal surgery for spina bifida. This is now performed in selected patients and presents an additional therapeutic alternative for expectant mothers carrying a fetus with MMC.

Colon atresia and frontal encephalocele: a rare association.

The association of colonic atresia with craniofacial anomalies has been well described and probably represents a malformative event that occurs in the early embryonal period. We present a case of an infant with colonic atresia and a frontal encephalocele and believe this to be a newly reported association. We review possible pathogenic mechanisms.

Sincipital encephaloceles.

An encephalocele is a protrusion of the cranial contents beyond the normal confines of the skull through a defect in the skull and the facial bones. Encephaloceles are classified according to their contents, site of exit through the skull/facial bones, and the path traversed through the face. Sincipital encephaloceles are the most common variety seen in the Asian population. Sincipital encephaloceles have been classified by Suwanwela and Suwanwela (1972) into frontoethmoidal, interfrontal, and those associated with craniofacial clefts. Correction of encephaloceles can be done in 1 stage or multiple stages and consists of excision of the encephalocele sac, repair of the bony defect, correction of hypertelorism/telecanthus, and correction of associated deformities such as trigonocephaly and the "long nose."

Prenatal screening and diagnosis of neural tube defects.

This review article discusses prenatal screening and diagnosis of neural tube defects (NTD). High detection rates occur in countries operating ultrasound screening programmes because classical two-dimensional ultrasound cranial signs (lemon shaped head, banana cerebellum, ventriculomegaly) are important diagnostic clues to the presence of spina bifida. Careful evaluation of both the spine and a search for other abnormalities is warranted. Important prognostic information for spina bifida relates to the lesion level, with a "watershed" between L3 and L4 marking a very high chance of being wheelchair bound with the higher lesions. Three-dimensional ultrasound using multiplanar views can achieve diagnostic accuracy within one vertebral body in around 80% of patients. There are high rates of pregnancy termination for spina bifida in many European countries, but the use of new imagining techniques allow better prediction of outcome, and consequently a refinement of prenatal counselling.

Fronto-ethmoidal encephalocele in a historical skull with artificial deformation and no signs of chronic elevated intracranial pressure.

The intentional deformation of human skulls in the living being was one of the most curious rituals performed in historical and ancient times. It is thought that these practices cause chronic elevated intracranial pressure and subsequent symptoms of cognitive impairment. In this report, we examine such an artificially deformed skull dating from the sixteenth century that in addition shows a fronto-ethmoidal encephalocele. However, although the mild encephalocele was already manifest at birth and deformation practices were performed over years, the encephalocele did not progress into a more severe status. We conclude that the intentional deformation of skulls does not lead to chronic elevated intracranial pressure and mental retardation.

Meckel-Gruber syndrome: pathologic manifestations, minimal diagnostic criteria, and differential diagnosis.

This article provides an overview of the major pathologic manifestations of Meckel-Gruber syndrome, current knowledge about its pathogenesis, minimal diagnostic criteria, and differential diagnosis. Typical sonographic findings (occipital encephalocele, postaxial polydactyly, and cystic enlargement of the kidneys) allow for diagnosis of most cases before the 14th week of gestation, but the pathologist may encounter clinically unsuspected or atypical cases that require morphologic confirmation. In these cases, a meticulous autopsy is necessary to establish the diagnosis of Meckel-Gruber syndrome.

Neurocutaneous melanosis associated with Dandy-Walker malformation and a meningohydroencephalocele. Case report.

Neurocutaneous melanosis and Dandy-Walker malformation are both forms of rare congenital neurodysplasia. Interestingly, 8 to 10% of patients with neurocutaneous melanosis also harbor an associated Dandy-Walker malformation, indicating that these developmental abnormalities share a common origin. The authors describe a case of neurocutaneous melanosis associated with Dandy-Walker malformation and an occipital meningohydroencephalocele with a giant melanotic nevus. Multiple congenital liver masses were also observed in the infant. The occipital nevus was totally excised, and ventriculoperitoneal and cyst-peritoneal shunts were created to prevent subsequent hydrocephalus. Findings in this case support the possibility that excessive melanocytes hinder normal mesenchymal development, causing Dandy-Walker malformation and an occipital meningocele.

[Prenatal imaging of the Meckel-Gruber syndrome].

A 32 years old woman, gravida 2 para 1, presented at 27 + 5 weeks' gestation with a large fetal head for the gestational age, an occipital encephalocele and ventriculomegaly. Both fetal kidneys were large, echogenic and multicystic, but oligohydramnion was not observed. Post-axial polydactyly of the fetal feet was demonstrated. The Meckel-Gruber syndrome was diagnosed, but termination of pregnancy was declined. Three weeks later, the patient spontaneously delivered an 1890 grams live-born female. The newborn died 2 days later in the neonate intensive care unit.

Meckel Gruber Syndrome--a case report.

Meckel Gruber Syndrome is a rare syndrome inherited as Mendelian autosomal recessive condition. The affected infant usually has a large occipital encephalocoele associated with renal cysts and sometimes polydactyly. The prognosis is poor. The affected child is still born or dies early in infancy. If diagnosis is done by prenatal ultrasound examination termination of pregnancy can be done.

[Embryology of the sphenoid bone]. / Développement embryonnaire du sphénoïde.

The sphenoid bone represents a complex structure in terms of anatomy and embryology. Indeed, it is formed by the fusion of different primordia whose embryonic origins are different. In mammals, it is possible to distinguish two components of this bone: the orbitosphenoid and the basi-post-sphenoid derive from the cephalic mesoderm whereas the alisphenoid and the basi-pre-sphenoid are from neural crest cell origin. The genetic control of the development of these two components is different further increasing the heterogeneity of these components. The sphenoid bone has been linked with several developmental diseases: chordomas, tumors arising from notochordal remnants; persistence of the craniopharyngeal canal may result in the occurrence of trans-sphenoidal encephaloceles.