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

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.

Open Fetal Surgery for Ventricular-Amniotic Valve Implantation in Aqueductal Stenosis-Dependent Severe Fetal Hydrocephalus: A Case Report with 7-Year Follow-Up

INTRODUCTION

Fetal ventriculomegaly is one of the most commonly diagnosed central nervous system pathologies of the second trimester, occurring with a frequency of 0.3-0.5/1,000 births. Severe fetal ventriculomegaly (SVM) may necessitate intrauterine intervention. Most such interventions have been made percutaneously with ultrasound guidance insertion of a pigtail catheter, which sadly often became obstructed or migrated.

CASE PRESENTATION

Our case report presents the possibility of ventriculo-amniotic valve implantation (VAVI) by classic hysterotomy in isolated severe fetal hydrocephalus (IVSM) due to aqueductal stenosis. The patient was operated on similarly to open fetal surgery MOMS criteria at 24+4/7 GA, with an initial lateral ventricular dimension of 22.5 mm. A female newborn was delivered by elective cesarean section at 31+1/7 GA due to PPROM (Apgar 10' 8 points, birth weight 1,600 g), required CPAP, and removal of the drainage system due to infection and narrow lateral ventricles. Evans index (EI) gradual increase and clinical symptoms of high-pressure hydrocephalus after 10 days required a ventricle-peritoneal shunt (VPS) implantation. The newborn was discharged home after 28 days with stabile hydrocephalus (EI: 0.59-0.6), in good clinical condition. The 7-year follow-up was complicated by epilepsy, VPS shunt infections, delay in motor and intellectual functions (mild to moderate), and symptoms of atypical autism, the phenotype possibly related to a variant in ZEB2 gene.

CONCLUSION

Intrauterine VAVI is a one-step procedure that is effective in draining CFS. The limitations of the method remain complications due to preterm labor and infection of the drainage system.

Prenatal Diagnosis of Fetal Aqueductal Stenosis: A Multicenter Prospective Observational Study through the North American Fetal Therapy Network

INTRODUCTION

A critical component of an evidence-based reassessment of in-utero intervention for fetal aqueductal stenosis (fetal AS) is determining if the prenatal diagnosis can be accurately made at a gestational age amenable to in-utero intervention.

METHODS

A multicenter, prospective, observational study was conducted through the North American Fetal Therapy Network (NAFTNet). Pregnancies complicated by severe central nervous system (CNS) ventriculomegaly (lateral ventricle diameter >15 mm) not secondary to a primary diagnosis (myelomeningocele, encephalocele, etc.) were recruited at diagnosis. Imaging and laboratory findings were recorded in an online REDCap database. After evaluation, investigators were asked to render their degree of confidence in the diagnosis of fetal AS. The prenatal diagnosis was compared to the postnatal diagnosis obtained through neonatal neuroimaging. Performance characteristics of ultrasound and magnetic resonance imaging (MRI) were calculated, as was the mean gestational age at diagnosis.

RESULTS

Between April 2015 and October 2022, eleven NAFTNet centers contributed 64 subjects with severe fetal CNS ventriculomegaly. Of these, 56 had both prenatal and postnatal diagnoses recorded. Ultrasound revealed 32 fetal AS true positives, 4 false positives, 7 false negatives, and 13 true negatives, rendering a sensitivity of 0.82, a specificity of 0.76, a positive predictive value of 0.89, and a negative predictive value of 0.65. The mean gestational age at diagnosis by ultrasound was 25.5 weeks (std +/- 4.7 weeks). The proportion of agreement (true positive + true negative/n) was highest at 24 weeks gestation. For fetal MRI (n = 35), the sensitivity for fetal AS was 0.95, specificity was 0.69, positive predictive value was 0.84, and negative predictive value was 0.90. MRI was performed at 25 weeks on average.

CONCLUSION

The prenatal diagnosis of fetal AS can be made with accuracy at a gestational age potentially amenable to in-utero intervention. Only 7% of subjects were incorrectly diagnosed prenatally with fetal AS by ultrasound and 11% by MRI. Diagnostic accuracy of fetal AS will likely improve with increased experience.

Fetal Endoscopic Third Ventriculostomy Is Technically Feasible in Prenatally Induced Hydrocephalus Ovine Model

BACKGROUND

Congenital obstructive hydrocephalus generates progressive irreversible fetal brain damage by ventricular enlargement and incremental brain tissue compression that leads to maldevelopment and poor clinical outcomes. Intrauterine treatments such as ventriculo-amniotic shunting have been unsuccessfully tried in the eighties.

OBJECTIVE

To assess if prenatal endoscopic third ventriculostomy (ETV) is feasible in a large animal model and optimize this technique for ventricular decompression and potential arrest of fetal brain damage in fetal lambs.

METHODS

We generated hydrocephalus in 50 fetal lambs by injecting a polymeric agent into the cisterna magna at midgestation (E85). Subsequently, 3 weeks later (E105), fetal ETV was performed using a small rigid fetoscope. The endoscopy entry point was located anterior to the coronal suture, 7 mm from the midline.

RESULTS

We obtained clear visualization of the enlarged lateral ventricles by endoscopy in the hydrocephalic fetal lambs. The floor of the third ventricle was bluntly perforated and passed with the scope for a successful ETV. Total success was achieved in 32/50 cases (64%). Causes of failure were blurred vision or third ventricle obliteration by BioGlue in 10/50 (20%) cases, anatomic misdirection of the endoscope in 5 (10%) cases, 2 cases of very narrow foramen of Monro, and 1 case of choroid plexus bleeding. If we exclude the cases artificially blocked by the polymer, we had a successful performance of prenatal-ETV in 80% (32/40) of hydrocephalic fetuses.

CONCLUSION

Despite the inherent difficulties arising from ovine brain anatomy, this study shows that innovative fetal ETV is technically feasible in hydrocephalic fetal lambs.

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.

Hospital incidence and costs of congenital hydrocephalus in Spain: a multicenter retrospective study

BACKGROUND

Congenital hydrocephalus continues to represent a therapeutic challenge; however, few studies are available evaluating its hospital incidence and medical costs in Spain. This study aimed to review the profile of patients with this disorder admitted in Spanish hospitals and to estimate medical costs at the hospital level.

METHODS

Records of hospital admissions of patients with congenital hydrocephalus between 2010 and 2019 were obtained from a Spanish hospital discharge database and analyzed in a retrospective multicenter study.

RESULTS

A third of the patients included in the study were perinatal patients, however, the hospitalization rate in this group was higher to that in patients over 1 year of age. Perinatal patients required more ICU admissions and longer hospital stays, with more frequent surgical interventions and mechanical ventilation. The mean medical cost associated to congenital hydrocephalus was €9610 per admission, with significantly higher costs found in perinatal patients.

CONCLUSIONS

This study provides novel data on the hospital costs of congenital hydrocephalus in Spain. The hospital medical costs of this disorder have decreased over the past decade for perinatal patients but not in those aged 1 year and older, which should be considered in upcoming healthcare plans and resource allocation decisions.

Diagnosis, management, and neurodevelopmental outcomes of fetal hydrocephalus: an observational prospective study

The etiology of fetal hydrocephalus is complex, and the outcome of fetal neurodevelopment after birth is also different. The purpose of this study is to conduct anti-infection of hydrocephalus fetuses with non-specific infection, and observe their neurodevelopment after birth, so as to provide clinical basis for further guidance and management of fetal hydrocephalus. Eighteen single pregnant women with fetal hydrocephalus confirmed by intrapartum ultrasonography in the Second Xiangya Hospital between July 1, 2019, and December 1, 2020, were included. Pelvis MRI, NITP, amniotic fluid/umbilical cord blood puncture, infection index, TORCH, and other examinations were completed during pregnancy. If the patient's infection index is elevated, the second-generation cephalosporin will be used for anti-infection therapy, and the development of fetal hydrocephalus, growth, and neurodevelopment after birth will be observed. Fetal hydrocephalus subsided in 3 cases (25%, 95% CI [0%, 53.7%]) remained stable in 6 cases (50%, 95% CI [16.8%, 83.2%]), progressed in 2 cases (16.7%, 95% CI [0%, 41.4%]), and terminated pregnancy in 1 case (8.7% [0%, 26.7%]). Of the 6 untreated patients, pregnancy was terminated in 3 (50%), hydrocephalus remained stable in 2 (33.3%), and spontaneous resolution in 1 case (16.7%). Fourteen patients delivered successfully, including 11 children with no obvious abnormalities in growth and development, 1 with mild growth retardation and 2 with moderate growth retardation. Anti-infective therapy in the case of non-specific infection or maternal infection can partially prevent the progression of hydrocephalus.

Prenatal diagnosis of a nonsense mutation in the L1CAM gene resulting in congenital hydrocephalus: A case report and literature review

Congenital hydrocephalus is frequently caused by mutations in the L1 cell adhesion molecule (L1CAM) gene. The purpose of the present study was to identify possible causes of fetal hydrocephalus in a Chinese family. The samples from the parents and the hydrocephalic fetus were collected. Whole-exome sequencing and in-depth mutation analysis were performed. The identified variant, c.1267C>T.(p.Q423X), is situated on exon 11 of L1CAM gene (chromosome X:153134975). The fetus was confirmed to be hemizygous for the nonsense mutation and the mother was a heterozygous carrier. The mutation turns a glutamine into a premature stop codon at amino acid position 423. In conclusion, in the present study, a nonsense mutation in the L1CAM gene was identified during the prenatal diagnosis of a congenital hydrocephalic fetus from a Chinese family. The diagnosis highlighted the necessity of genetic screening for prenatal diagnosis.

Similar outcomes for antenatally or postnatally acquired haemorrhages

This commentary is on the systematic review by Dunbar et al. on pages 144–155 of this issue.