Clinical Outcomes of Isolated Congenital Aqueductal Stenosis

Isolated Fetal Ventriculomegaly: Diagnosis and Treatment in the Prenatal Period

Fetal ventriculomegaly (VM) is a defect of the central nervous system, typically diagnosed during the second-trimester ultrasound in fetuses with an atrial diameter (AD) of >10 mm. Non-isolated ventriculomegaly (NIVM) is heterogeneous in nature, coexisting with additional intracranial and/or extracranial malformations and genetic syndromes, resulting in an unfavorable prognosis for the further development of the child. Both the pregnancy management and counseling are dependent on the findings of combined ultrasound/MRI, genetic testing, and gestational age at diagnosis. The purpose of this review is to propose a hypothesis that diagnostic advancements allow to define the process of identification of the isolated forms of VM (IVM). Based on the evidence presented in the literature, we consider whether prenatal decompression for severe isolated VM (ISVM) is supported by the experimental trials and whether it might be implemented in clinical practice. Also, we describe the evolution of the diagnostic methods and expert opinions about the previously used prenatal decompression techniques for ISVM. In conclusion, we introduce the idea that fetal surgery centers have either reached or nearly reached the necessary level of expertise to perform such procedures. Endoscopic cystoventriculostomy (ETV) appears to be the most promising, as it is associated with minimal perinatal complications and favorable neurological outcomes in the neonatal period. Randomized trials with long-term neurodevelopmental follow-up of children who underwent prenatal decompression due to ISVM are necessary.

Fetal Cerebral Ventriculomegaly: A Narrative Review and Practical Recommendations for Pediatric Neurologists

Fetal cerebral ventriculomegaly is one of the most common fetal neurological disorders identified prenatally by neuroimaging. The challenges in the evolving landscape of conditions like fetal cerebral ventriculomegaly involve accurate diagnosis and how best to provide prenatal counseling regarding prognosis as well as postnatal management and care of the infant. The purpose of this narrative review is to discuss the literature on fetal ventriculomegaly, including postnatal management and neurodevelopmental outcome, and to provide practice recommendations for pediatric neurologists.

Endoscopic third ventriculostomy (ETV) or ventriculoperitoneal shunt (VPS) for paediatric hydrocephalus due to primary aqueductal stenosis

PURPOSE

The purpose of this study was to compare outcomes of endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) in children with symptomatic triventricular hydrocephalus due to primary aqueductal stenosis.

METHOD

This is a retrospective analytical study. Patients who underwent either ETV or VPS as the first procedure for hydrocephalus due to primary aqueductal stenosis were included in the study.

RESULT

A total of 89 children were included in the study for analysis. The mean age was 8.4 years. Forty-four (49.4%) had their first surgery as ETV and 45 (50.6%) had their first surgery as VPS. Overall, 34 (38.2%) patients required a second surgery (either ETV or VPS) for persistent or recurrent hydrocephalus. The mean follow-up duration was 832.9 days. The overall complication rate was 13.5%. The mean timing of the second surgery after index surgery was 601.35 days. Factors associated with a second surgery were the presence of complications, high protein in cerebrospinal fluid, the relative change of frontal-occipital horn ratio (FOHR) and Evans' index. The survival of the first surgery was superior in ETV (751.55 days) compared to VPS (454.49 days), p = 0.013. The relative change of fronto-occipital horn index ratio (FOIR) was high in the VPS (mean 7.28%) group compared to the ETV (mean 4.40%), p = 0.001 group.

CONCLUSION

Overall procedural survival was better after ETV than VPS for hydrocephalus due to aqueductal stenosis. VPS causes more reduction in linear indices of ventricles as compared to ETV, however, is not associated with the success or complication of the procedure.

In vitro and in vivo assessment of a novel ultra-flexible ventriculoamniotic shunt for treating fetal hydrocephalus

Fetal aqueductal stenosis (AS) is one of the most common causes of congenital hydrocephalus, which increases intracranial pressure due to partial or complete obstruction of cerebrospinal fluid (CSF) flow within the ventricular system. Approximately 2-4 infants per 10,000 births develop AS, which leads to progressive hydrocephalus, which enlarges the head often necessitating delivery by cesarean section. Most babies born with AS are severely neurologically impaired and experience a lifetime of disability. Therefore, a new device technology for venticuloamniotic shunting is urgently needed and has been studied to ameliorate or prevent fetal hydrocephalus development, which can provide a significant impact on patients and their family's quality of life and on the decrease of the healthcare dollars spent for the treatment. This study has successfully validated the design of shunt devices and demonstrated the mechanical performance and valve functions. A functional prototype shunt has been fabricated and subsequently used in multiple in vitro tests to demonstrate the performance of this newly developed ventriculoamniotic shunt. The shunt contains a main silicone-nitinol composite tube, a superelastic 90° angled dual dumbbell anchor, and an ePTFE valve encased by a stainless-steel cage. The anchor will change its diameter from 1.15 mm (collapsed state) to 2.75 mm (deployed state) showing up to 1.4-fold diameter change in human body temperature. Flow rates in shunts were quantified to demonstrate the valve function in low flow rates mimicking the fetal hydrocephalus condition showing "no backflow" for the valved shunt while there is up to 15 mL/h flow through the shunt with pressure difference of 20 Pa. In vivo ovine study results show the initial successful device delivery and flow drainage with sheep model.

Diagnosis and Surgical Management of Neonatal Hydrocephalus

Neonatal hydrocephalus represents an important pathological condition with significant impact on medical care and neurocognitive development. This condition requires early recognition, appropriate medical and surgical management, and long-term surveillance by clinicians and pediatric neurosurgeons. Common etiologies of neonatal and infant hydrocephalus include intraventricular hemorrhage related to prematurity with subsequent post-hemorrhagic hydrocephalus, myelomeningocele, and obstructive hydrocephalus due to aqueductal stenosis. Clinical markers of elevated intracranial pressure include rapid increases in head circumference across percentiles, elevation and firmness of the anterior fontanelle, splitting or splaying of cranial sutures, upgaze palsy, lethargy, frequent emesis, or episodic bradycardia (unrelated to other comorbidities). Complementing these clinical markers, imaging modalities used for the diagnosis of neonatal hydrocephalus include head ultrasonography, brain magnetic resonance imaging, and head computed tomography in urgent or emergent situations. Following diagnosis, temporizing measures may be employed prior to definitive treatment and include ventricular access device or ventriculo-subgaleal shunt insertion. Definitive surgical management involves permanent cerebrospinal fluid (CSF) diversion via CSF shunt insertion, or endoscopic third ventriculostomy with or without choroid plexus cauterization. Surgical decision-making and approaches vary based on patient age, hydrocephalus etiology, neuroanatomy, imaging findings, and medical comorbidities. Indications, surgical techniques, and clinical outcomes of these procedures continue to evolve and elicit significant attention in the research environment. In this review we describe the epidemiology, pathophysiology, clinical markers, imaging findings, early management, definitive surgical management, and clinical outcomes of pediatric patients with neonatal hydrocephalus.

Neuroophthalmological manifestations of congenital aqueductal stenosis

OBJECTIVE

Congenital aqueductal stenosis (CAS) is a common etiology of hydrocephalus that occurs in a subset of infants and may be linked to an increased incidence of ophthalmological abnormalities and delayed developmental milestones. Although hydrocephalus is common and widely studied, sparse literature exists on patients with isolated (no identifiable genetic link) CAS along with analysis of ophthalmological manifestations. In this study, the authors sought to describe the ophthalmological abnormalities and delayed developmental milestones of patients with isolated CAS.

METHODS

Data of patients with CAS were prospectively entered and monitored in a surgical database maintained by the Department of Neurological Surgery at Children's Hospital of Pittsburgh from January 2005 to October 2016. Patients with a family history of congenital hydrocephalus, positive testing for genetic forms of aqueductal stenosis, other congenital abnormalities suggesting an underlying genetic syndrome, and stenosis/obstruction due to secondary causes were excluded from this study. Prenatal and perinatal history, CSF diversion history, and a variety of outcomes, including ophthalmological deficits and developmental milestones, were collected and analyzed.

RESULTS

A total of 41 patients with isolated CAS were identified, with a mean follow-up duration of 6 years. Among that cohort, 26 patients (63.4%) developed neuroophthalmological complications, which were further stratified. Fourteen patients (34.1%) developed strabismus and 11 (26.8%) developed astigmatism, and 1 patient (2.4%) with papilledema was recorded. Among patients with ophthalmological abnormalities, 76.9% had delayed developmental milestones (p = 0.045).

CONCLUSIONS

Patients with CAS were found to have increased risk of ophthalmological abnormalities requiring correction, along with an increased risk of delayed developmental milestones. Importantly, there was a significant correlation between the development of ophthalmological abnormalities and delayed developmental milestones that was independent of CSF diversion history. Larger patient cohort studies are required to explore whether earlier development of hydrocephalus, as is the case in CAS, causes elevated rates of neurological and ophthalmological complications, and if earlier CSF diversion correlates with improved outcomes.

Discharge of Medically Complex Infants and Developmental Follow-up

At the time of discharge from the NICU, many infants have ongoing complex medical issues that will require coordinated, multispecialty follow-up. Discharge planning and transfer of care for infants with medical complexity require a multidisciplinary team effort that begins early during the NICU hospitalization. It is critical that the primary care physician is involved in this process because he or she will serve as the chief communicator and coordinator of care after discharge. Although some infants with medical complexity may be followed in specialized multidisciplinary NICU follow-up clinics, these are not universally available. The responsibility then falls to the primary care physician to coordinate with different subspecialties based on the infant's needs. Many infants with medical complexity are technology-dependent at the time of discharge and may require home oxygen, ventilators, monitors, or tube feeding. Prematurity, critical illness, and prolonged NICU hospitalization that lead to medical complexity also increase the risk of neurodevelopmental delay or impairment. As such, these infants will not only require routine developmental surveillance and screening by the primary care physician but also should be followed longitudinally by a neurodevelopmental specialist, either a developmental-behavioral pediatrician or a neonatologist with experience in neurodevelopmental assessment.

Not all ventriculomegaly is created equal: diagnostic overview of fetal, neonatal and pediatric ventriculomegaly

Fetal ventriculomegaly refers to a condition in which there is enlargement of the ventricular spaces, typically on prenatal ultrasound. It can be associated with other CNS or extra-CNS abnormalities, and this relationship is crucial to understand as it affects overall neonatal outcome. Isolated ventriculomegaly has been described in the literature with variable clinical outcome. Typically, outcome is based on the etiology and degree of ventriculomegaly. When associated with a pathologic condition, ventriculomegaly can be a result of hydrocephalus. While initial diagnosis is usually made on prenatal ultrasound, fetal magnetic resonance imaging is preferred to further elucidate any associated CNS malformations. In this paper, the authors aim to provide a comprehensive review of the diagnosis, associated etiologies, prognosis, and treatment options related to fetal, neonatal, and pediatric ventriculomegaly and hydrocephalus. In addition, preliminary data is provided from our institutional cohort of patients with a prenatal diagnosis of ventriculomegaly followed through the perinatal period.

Fetal brain damage in congenital hydrocephalus

BACKGROUND

Congenital hydrocephalus (HCP) is a developmental brain disorder characterized by the abnormal accumulation of cerebrospinal fluid within the ventricles. It is caused by genetic and acquired factors that start during early embryogenesis with disruption of the neurogerminal areas. As might be expected, early-onset hydrocephalus alters the process of brain development leading to irreparable neurological deficit. A primary alteration of the ependyma/neural stem cells (affecting vesicle trafficking and abnormal cell junctions) leads to its loss or denudation and translocation of neural progenitor cells (NPCs) and neural stem cells (NSCs) into the cerebrospinal fluid (CSF). Under these abnormal conditions, morphological and functional processes, underlying the concept of astroglial reaction, are initiated in an attempt to recover homeostasis in the periventricular zone. This astroglial reaction includes astrocyte hypertrophy, hyperplasia, and development of a new layer with reorganized functional features that resemble the ependyma. Despite decades of research, there is a lack of information concerning the biological basis of the brain abnormalities that are associated with HCP.

DISCUSSION

The present review of current literature discusses the neuropathological changes during gestation following the onset of congenital hydrocephalus and the unanswered questions into the pathophysiology of the disease. A better understanding of those missing points might help create novel therapeutic strategies that can reverse or even prevent the ultimate neurological impairment that affects this population and improve long-term clinical outcome.

Fetal therapy for congenital hydrocephalus-where we came from and where we are going

Despite unfavorable outcomes during the early experience with in utero intervention for congenital hydrocephalus, improvements in prenatal diagnosis, patient selection, and fetal surgery techniques have led to a renewed interest in fetal intervention for congenital hydrocephalus. Research studies and clinical evidence shows that postnatal cerebrospinal fluid diversion to release intraventricular pressure and cerebral mantle compression usually arrives late to avoid irreversible brain damage. Make sense to decompress those lateral ventricles as soon as possible during the intrauterine life when hydrocephalus is antenatally detected. We present a historical review of research in animal models as well as clinical experience in the last decades, traveling until the last years when some research fetal therapy groups have made significant progress in recapitulating the prenatal intervention for fetuses with congenital obstructive hydrocephalus.

Fetal aqueductal stenosis: Prenatal diagnosis and intervention

Fetal severe central nervous system ventriculomegaly is associated with poor neurologic outcomes, usually driven by a primary malformation, deformation, or disruption of brain parenchyma. In utero shunting of excess cerebrospinal fluid (CSF) in hopes of improving neurologic outcomes was attempted in the 1980s but was abandoned due to perceived lack of effect, likely due to technological limitations of the time that precluded proper patient selection. Little progress on the antenatal management of severe ventriculomegaly has been made in the intervening decades. A multidisciplinary, evidence-based reassessment of ventriculoamniotic shunting for isolated fetal aqueductal stenosis (FAS), a unique form of severe ventriculomegaly (supratentorial intracranial hypertension), is currently underway. An accurate diagnosis of FAS must precede in utero intervention. Magnetic resonance imaging (MRI) will be an excellent adjunct to high-resolution prenatal ultrasound and next-generation genetic testing to correctly diagnose FAS in a timely fashion while excluding other intracranial and extracranial anomalies. This manuscript will briefly discuss the history, current management, and future directions of the prenatal diagnosis and potential intervention for FAS.

Histologic Appearance of Iatrogenic Obstructive Hydrocephalus in the Fetal Lamb Model

INTRODUCTION

Documentation of histologic findings associated with congenital hydrocephalus in the fetal lamb model is a critical step in evaluating the efficacy of ventriculoamniotic shunting in the human fetus.

METHODS

Four fetal sheep had hydrocephalus induced at approximately 95 days' gestation. Two co-twins remained as controls. The ewes were euthanized at term. The lamb brains were fixed in formalin, paraffin-embedded, stained, and analyzed for markers of neuropathology. Astrocytosis, microgliosis, and axonal loss were assessed with immunocytochemistry for glial fibrillary acidic protein, ionized calcium-binding adapter, and neurofilament/amyloid precursor protein, respectively. Cortical gray matter extracellular matrix was assessed with staining for the lectin Wisteria Floribunda agglutinin.

RESULTS

Hydrocephalic lamb brains demonstrated deep white matter damage with loss of projecting axonal tracts in regions physically distorted by hydrocephalus, similar to that seen in hydrocephalic humans. There was no evidence of abnormal neocortical neuronal migration; however, there was evidence for delayed maturation of the neocortical gray matter, possibly from increased intracerebral pressure and subsequent ischemia. Control lamb brains demonstrated none of the above findings.

CONCLUSION

This histological approach can be used to further define the mechanism of brain damage associated with hydrocephalus and interpret the efficacy of ventriculoamniotic shunting on fetal lamb brain neuroanatomy.