The prepontine block and its relevance for the development and treatment of hydrocephalus.

OBJECTIVE: Pulsatile CSF flow patterns include flow through the ventricles to the subarachnoid space and cisterns and from the infra- to the supratentorial subarachnoid space. In this study, we demonstrate how an obstruction at the level of the prepontine space may lead to obstructive hydrocephalus with specific radiological characteristics, as well as the implications for treatment options. METHODS: We retrospectively collected data of patients who underwent surgery between February 2010 and December 2022 for hydrocephalus secondary to a suspected prepontine block. One additional patient diagnosed with prepontine block who did not undergo surgery was also included. We excluded patients with a background of previous unrelated neurosurgical procedures or CNS infections. RESULTS: Six children and two adults were included. Three presented with hydrocephalus on imaging, without any other underlying pathology. Five had a suprasellar arachnoid cyst, with its lower border abating the pons and occluding the spinal subarachnoid space (SAS). All cases had an open aqueduct on T2 sagittal sequences, as well as an infracerebellar or retrocerebellar CSF collection. In most cases, a horizontal web was identified in the prepontine region. Seven cases were treated with an endoscopic fenestration. One patient subsequently underwent a shunt surgery. All the operated children reached normal developmental milestones after surgery. CONCLUSIONS: This paper describes a rather small series of cases where clear obstruction was observed at the level of the prepontine subarachnoid space. We believe this anatomical subtlety adds to a better understanding of CSF pathways and the role of ETV in treating hydrocephalus, focusing on a small subgroup of patients without a clear obstruction.

Advanced cerebrospinal fluid flow MRI findings of aqueductal stenosis caused by web.

BACKGROUND: The aqueductal web (AW) is one of the causes of aqueductus stenosis (AS). Recent advances in Magnetic resonance (MR) imaging have enabled us to better reveal the cerebrospinal fluid (CSF) flow dynamics and aqueductal anatomy. PURPOSE: The aim of this study is to evaluate the CSF flow dynamics of patients with AW with phase contrast Magnetic resonance imaging (MRI) and compare them with the imaging findings. MATERIALS AND METHODS: We evaluated 23 patients under 65-year-old age. On constructive interference in steady-state (T2 CISS) images, the width of prepontine cistern (PPC) and the width of Sylvian aqueduct (SA) were measured. Localization and number of webs were evaluated. The existence of flow at the aqueduct and the presence of spontaneous third ventriculostomy (STV) were evaluated on sagittal Sampling Perfection with Application optimized Contrast (SPACE) sequences. RESULTS: Of the 23 patients included in the study, 11 were male and 12 were female. The mean age was 34.02 (0.5-64). A total of 31 AWs were detected in 23 patients. Six of 23 patients (26.1%) had STV and 17 of those not. Four of 23 patients (17.4%) had aqueductal flow on SPACE sequences. The PPC distance was significantly wider in patients with STV (median: 6.7-4.5, interquartile range (IQR): 1.35, p = 0.004). In the cases where artifact secondary to flow is observed in SPACE sequences in aqueduct, the Evan index (EI) was significantly lower (median: 0.2955-0.3900, IQR: 0.03-0.14, p < 0.001). CONCLUSION: In patients with a low EI, there may be flow in the SA even if there is a web. In patients with a wide PPC distance, it is necessary to consider the presence of STV and evaluate the presence of flow with the SPACE sequences.

Endoscopic transaqueductal stent placement for tumor-related aqueductal compression in pediatric patients: surgical consideration, technique, and results.

PURPOSE: Endoscopic transaqueductal stenting has become a well-accepted treatment option for a selected small subset of aqueductal stenosis-related obstructive hydrocephalus. However, transaqueductal stenting poses unique challenges and risks which requires critical consideration. This report discusses the clinical experiences with transaqueductal stenting for periaqueductal tumor-related aqueductal stenosis focusing on pediatric patients. METHODS: A retrospective analysis of all patients undergoing endoscopic TAS from 01/1993 to 01/2022 in the author's departments was performed. Demographic, clinical, radiological, and intraoperative endoscopic data were evaluated. All patients with AS-related occlusive hydrocephalus that was treated with TAS were analyzed and prospectively followed. Special attention has been given to providing insights into indications, surgical technique, and limitations. RESULTS: Out of 28 endoscopic transaqueductal endoscopis stenting procedures, five procedures were performed on periaqueductal tumor-related obstructive hydrocephalus, two children and three adult patients. CSF pathway was obstructed by tumor located in the aqueduct in 2, by tumor in the thalamus/mesencephalon in 1, by a tumor within the third ventricle in 1, and by a tumor of the lamina tecti in 1. Simultaneously with transaqueductal stenting, 2 endoscopic third ventriculostomies (ETV), 3 tumor biopsies, and 1 tumor resection were performed. Postoperative complications included the following: CSF fistula (1 case), and asymptomatic fornix contusion (1 case). A working aqueductal stent was achieved in all cases based on clinical follow-up evaluation. Postoperatively, all patients showed improvement or resolution of their symptoms. The mean follow-up period was 25.2 months (range, 1-108 months). One patient died due to tumor progression during early follow-up. No stent migration was seen. CONCLUSION: Endoscopic third ventriculostomy remains the gold standard for treatment of CSF circulation obstructions with lesions in the posterior third ventricle and aqueduct. Transaqueductal stenting for periaqueductal tumor-related aqueductal compression is technically feasible. However, because of the potential high risks and subtle advantages compared with ETV transaqueductal stenting, it might be indicated in a small subset of well-selected patients if alternative treatment options are not at hand.

Spontaneous Third Ventriculostomy in Cases of Aqueductal Stenosis: A Retrospective Case Series.

BACKGROUND: Spontaneous third ventriculostomy (STV) is a rare occurrence in cases of obstructive hydrocephalus where the walls of the third ventricle rupture, communicating the ventricular system, and the subarachnoid space leading to arrest of active hydrocephalus. We aim to review our series of STVs while reviewing previous reports. METHODS: A retrospective review of cases undergoing cine phase-contrast magnetic resonance imaging (PC-MRI) from 2015 to 2022 of any age with imaging evidence of arrested obstructive hydrocephalus was performed. Patients in which aqueductal stenosis was radiologically evident and the presence of third ventriculostomy through which cerebrospinal fluid flow was detectable were included. Patients who previously underwent endoscopic third ventriculostomy were excluded. Data on patient demographics, presentation, and imaging details of STV and aqueductal stenosis were collected. We searched the PubMed database using the following keyword combination: ((("spontaneous ventriculostomy") OR ("spontaneous third ventriculostomy")) OR ("spontaneous ventriculocisternostomy")) including English reports of STV published between 2010 and 2022. RESULTS: Fourteen cases were included (7 adults, 7 pediatrics), all with history of hydrocephalus. STV occurred in the floor of the third ventricle in 57.1% of the cases, at the lamina terminalis in 35.7%, and at both sites in 1 case. Eleven publications reporting 38 cases of STV were identified from 2009 to date. Minimum follow-up period was 10 months and maximum follow-up is 77 months. CONCLUSIONS: In cases of chronic obstructive hydrocephalus, neurosurgeons should be minded with the possibility of the presence of an STV on cine phase-contrast magnetic resonance imaging leading to arrested hydrocephalus. The delayed flow at the aqueduct of Sylvius might not be the only determinant of the necessity of cerebrospinal fluid diversion and the presence of an STV should be factored into the neurosurgeon's decision considering the patient's clinical picture.

Bi-allelic variations in CRB2, encoding the crumbs cell polarity complex component 2, lead to non-communicating hydrocephalus due to atresia of the aqueduct of sylvius and central canal of the medulla.

Congenital hydrocephalus is a common condition caused by the accumulation of cerebrospinal fluid in the ventricular system. Four major genes are currently known to be causally involved in hydrocephalus, either isolated or as a common clinical feature: L1CAM, AP1S2, MPDZ and CCDC88C. Here, we report 3 cases from 2 families with congenital hydrocephalus due to bi-allelic variations in CRB2, a gene previously reported to cause nephrotic syndrome, variably associated with hydrocephalus. While 2 cases presented with renal cysts, one case presented with isolated hydrocephalus. Neurohistopathological analysis allowed us to demonstrate that, contrary to what was previously proposed, the pathological mechanisms underlying hydrocephalus secondary to CRB2 variations are not due to stenosis but to atresia of both Sylvius Aqueduct and central medullar canal. While CRB2 has been largely shown crucial for apico-basal polarity, immunolabelling experiments in our fetal cases showed normal localization and level of PAR complex components (PKCι and PKCζ) as well as of tight (ZO-1) and adherens (ß-catenin and N-Cadherin) junction molecules indicating a priori normal apicobasal polarity and cell-cell adhesion of the ventricular epithelium suggesting another pathological mechanism. Interestingly, atresia but not stenosis of Sylvius aqueduct was also described in cases with variations in MPDZ and CCDC88C encoding proteins previously linked functionally to the Crumbs (CRB) polarity complex, and all 3 being more recently involved in apical constriction, a process crucial for the formation of the central medullar canal. Overall, our findings argue for a common mechanism of CRB2, MPDZ and CCDC88C variations that might lead to abnormal apical constriction of the ventricular cells of the neural tube that will form the ependymal cells lining the definitive central canal of the medulla. Our study thus highlights that hydrocephalus related to CRB2, MPDZ and CCDC88C constitutes a separate pathogenic group of congenital non-communicating hydrocephalus with atresia of both Sylvius aqueduct and central canal of the medulla.

Flow volume measurement of arterial venous and cerebrospinal fluid in patients with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is usually described as an autoimmune disease, although the exact mechanism of the disease remains unknown. There have been studies reporting that venous flow abnormalities may be involved in the pathogenesis of MS or many of the associated clinical manifestations. OBJECTIVE: The aim of this study was to evaluate flow volumes of the middle cerebral artery (MCA), transverse sinus (TS), and cerebral aqueduct using phase contrast magnetic resonance imaging (PC-MRI) in relapsing-remitting MS patients and a control group. METHODS: We included 34 patients diagnosed by the McDonald criteria, revised in 2017, as well as 15 healthy controls matched by age and sex. The MRI scans were performed using a 1.5-T superconducting scanner. Axial T1-weighted, T2-weighted, and PC-MRI sequences were performed for the quantitative investigation of flow volume measurements. Quantitative analyses of flows were performed using flow analyses program PC-MRI angiography software. A circular region of interest was placed manually into the cerebral aqueduct, bilateral MCA, and TS. RESULTS: Flow volumes of the cerebral aqueduct and MCA were not statistically significant between the MS and control groups. The flow volumes of the TS for the patient group were lower than those of the control group, and this difference was statistically significant. CONCLUSIONS: A reduced TS flow volume in MS patients was noted in the present study when compared with the control group, suggesting a relation between venous pathologies and MS. Further studies are needed to understand whether this relation is causal or epiphenomenal.

ANTECEDENTES: A esclerose múltipla (EM) é comumente descrita como uma doença autoimune, embora seu mecanismo exato permaneça desconhecido. Há estudos que afirmam que anormalidades no fluxo venoso podem estar relacionadas à patogênese da EM ou a muitas das manifestações clínicas associadas. OBJETIVO: O objetivo deste estudo é avaliar os volumes de fluxo da artéria cerebral média (ACM), do seio transverso (ST) e do aqueduto cerebral usando ressonância magnética com contraste de fase (PC-MRI) em com EM recorrente-remitente. MéTODOS: Incluímos 34 pacientes diagnosticados pelos critérios de McDonald, revisados em 2017, além de 15 controles saudáveis pareados por idade e gênero. A ressonância magnética foi realizada usando um scanner supercondutor de 1,5 T. As sequências de PC-RM axiais, ponderadas em T1 e ponderadas em T2 foram realizadas para investigação quantitativa das medidas de volume de fluxo. As análises quantitativas de fluxo foram realizadas usando o software de angiografia PC-MRI do programa de análise de fluxo. Uma região circular de interesse foi localizada manualmente no aqueduto cerebral, ACM bilateral e ST. RESULTADOS: Os volumes de fluxo do aqueduto cerebral e da ACM não foram estatisticamente significantes entre o grupo de pacientes e os controles. Os volumes ST do grupo de pacientes foram menores que os do grupo controle, e essa diferença foi estatisticamente significante. CONCLUSõES: No presente estudo, um menor volume de fluxo ST foi registrado em pacientes com EM em comparação ao grupo controle, sugerindo uma relação entre patologias venosas e EM; Mais estudos são necessários para entender se essa relação é causal ou um fenômeno secundário.

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.

Acute hydrocephalus caused by a gelatin-sponge material: a case report.

Third ventricle lesions, especially those located proximally to the foramen of Monro, generally present with obstructive hydrocephalus symptoms. In this report, we present a case with acute obstructive hydrocephalus secondary to a gel-foam material. The patient has previously underwent an endoscopic cystectomy. At postoperative third month, she admitted to our hospital with the complain of headache. Neuroradiological imaging revealed triventricular hydrocephalus. A second endoscopic operation was performed, and a piece of gelatin-sponge material was detected at the level of cerebral aqueduct, which obstructed the flow of cerebrospinal fluid (CSF). The CSF flow was immediately restored after removing this material, and an additional third ventriculostomy was performed.

Case report: Flattening of the tectal plate in obstructive hydrocephalus with auto-ventriculostomy.

BACKGROUND: Obstructive hydrocephalus in adulthood can be caused by stenosis in the aqueductal area. Chronic changes lead to a dilatation of the lateral ventricles and ballooning of infratentorial recesses. In rare cases a rupture of the floor of the third ventricle (so-called spontaneous ventriculostomy) has been described in the literature.Case presentation: We present two cases of chronic obstructive hydrocephalus due to aqueductal stenosis in adult patients. Magnetic resonance imaging included phase-contrast-imaging and revealed significant flow through the floor of the third ventricle in keeping with spontaneous ventriculostomy. In addition to other typical changes associated with chronic hydrocephalus, a distinct flattening of the tectal plate could be identified in one case. CONCLUSION: We present two cases of spontaneous ventriculostomy in patients with chronic hydrocephalus. To our knowledge, flattening of the tectal plate has not yet been described in the literature and may be caused by continuous cerebrospinal fluid-pulsation.

Where the central canal begins: endoscopic in vivo description.

OBJECTIVE: Although evidence and descriptions of the central canal (CC) along the medulla oblongata and the spinal cord have been provided by several anatomical and radiological studies, a clear picture and assessment of the opening of the CC, or apertura canalis centralis (ACC), into the fourth ventricle is lacking, due to its submillimetric size and hidden position in the calamus scriptorius. METHODS: The authors reviewed all of their cases in which patients underwent ventricular transaqueductal flexible endoscopic procedures and selected 44 cases in which an inspection of the region of the calamus scriptorius had been performed and was suitable for study inclusion. Patients were divided into different groups, based on the presence or absence of a chronic pathological process involving the fourth ventricle. In each case, the visual appearance of the opening of the CC of the ACC was classified as no evidence (A0), indirect evidence (A1), or clear evidence (A2). Morphometric measurements were inferred from surrounding structures and the size of surgical tools visible in the field. RESULTS: The opening of the CC could be clearly observed in all cases (A1 4.5%, A2 95.5%). In normal cases, a lanceolate shape along the median sulcus was most frequently found, with an average size of 600 × 250 µm that became rounded and smaller in size in cases of hydrocephalus. The distance between the caudal margin of the ACC and the obex was about 1.8 mm in normal cases, 2.1 mm in cases of obstructive hydrocephalus, and 1 mm in cases of normal pressure hydrocephalus. The two wings of the area postrema, variable in size and shape, were sited just caudal to the opening. CONCLUSIONS: A flexible scope inserted through the cerebral aqueduct can approach the hidden calamus scriptorius like a pen fits into an inkpot. With this privileged viewpoint, the authors provide for the first time, to their knowledge, a clear and novel vision of the opening of the CC in the fourth ventricle, along with the precise location of this tiny structure compared to other anatomical landmarks in the inferior triangle.

RAQ: a novel surrogate for the craniospinal pressure-volume relationship.

OBJECTIVE: The intracranial pressure-volume relation contains information relevant for diagnostics of hydrocephalus and other space-occupying pathologies. We aimed to design a noise-resilient surrogate for this relationship that can be calculated from intracranial pressure (ICP) signals. APPROACH: The new surrogate, termed respiratory amplitude quotient (RAQ), characterizes the modulation of the cardiac pulse wave amplitude by the respiratory wave in the ICP time course. RAQ is defined as the ratio of the amplitude of the respiratory wave in the ICP signal to the amplitude of the respiration-induced variation in the course of the cardiac pulse wave amplitude. We validated the calculation of RAQ on synthetically generated ICP waveforms. We further extracted RAQ retrospectively from overnight ICP recordings in a cohort of hydrocephalus patients with aqueductal stenosis, age 55.8 ± 18.0 years, and a comparison group with hydrocephalus diagnosed by morphology in MRI, but not responsive to either external lumbar drainage or ventriculo-peritoneal shunting, age 72.5 ± 6.1 years. RAQ was determined for the full recordings, and separately for periods containing B-waves. MAIN RESULTS: We found a mean difference of less than 2% between the calculated values of RAQ and the theoretically determined equivalent descriptors of the synthetic ICP waveforms. In the overnight recordings, we found significantly different RAQ values during B-waves in the aqueductal stenosis (0.86 ± 0.11) and non-responsive hydrocephalus patient groups (1.07 ± 0.20), p = 0.027. In contrast, there was no significant difference in other tested parameters, namely pressure-volume index, elastance coefficient, and resistance to outflow. Neither did we find significant difference when considering RAQ over the full recordings. SIGNIFICANCE: Our results indicate that RAQ may function as a potential surrogate for the intracranial pressure-volume relation.

Central neurocytoma originating in third ventricle with expansion into the cerebral aqueduct and fourth ventricle: Case report and review of literature.

BACKGROUND: Central Neurocytomas (CNs) are rare brain tumors, making up less than 1% of all primary tumors within the CNS. They are commonly located in the lateral ventricles, and often present with visual changes and symptoms of obstructive hydrocephalus. Histopathology shows characteristics similar to ependymomas and oligodendrogliomas, however tumor cells display neuronal differentiation, and immunohistochemical stains typically for synaptophysin. Gross total resection is the most important prognostic indicator of survival. CASE DESCRIPTION: We describe the case of a 48-year-old male with a CN originating in the third ventricle with expansion through the cerebral aqueduct into the fourth ventricle. He presented with bi-frontal headaches, imaging revealed an avidly enhancing tumor occupying the inferior third ventricle, cerebral aqueduct, with expansion into the fourth ventricle. An interhemispheric craniotomy with a transcallosal transchoroidal approach to the third ventricle was performed, this provided a trajectory that paralleled the long axis of the tumor. Postoperative imaging confirmed a near total resection with linear residual enhancement on the anterior wall of the fourth ventricle. Intensity modulated radiotherapy was performed, 7-month follow-up imaging was clean. CONCLUSION: CNs are rare brain tumors, most commonly located within the lateral ventricles. We describe a rare case of a CN spanning from the third ventricle into the cerebral aqueduct and fourth ventricle. To our knowledge, this is only the fourth reported case of such a tumor. Surgical approach must be carefully selected, as gross total resection is the most important prognostic indicator.

Biventricular hydrocephalus secondary to aqueductal developmental venous anomaly.

Developmental venous anomaly (DVA) is the most common type of intracranial vascular malformation. These lesions are benign and are considered to be non-pathological variants of normal deep parenchymal veins. Although most of them are asymptomatic, a small subset of them located in aqueductal region have been reported to cause obstructive hydrocephalus. The authors present an interesting case of biventricular hydrocephalus secondary to a DVA located on the proximal aqueduct in an adolescent patient. This case is discussed with in corroboration with current literature and management recommendations.

A retrospective regional study of aqueduct stenosis and fourth ventricle outflow obstruction in the paediatric complex neurofibromatosis type 1 population; Aetiology, clinical presentation and management.

OBJECTIVES: Aqueduct stenosis (AS) and fourth ventricle outflow obstruction are rare associations of neurofibromatosis type 1 (NF1), resulting in ventriculomegaly and hydrocephalus requiring surgical treatment. This study aims to identify the prevalence of AS and its patterns of clinical presentation, aetiology and treatment in the paediatric complex NF1 population. PATIENTS AND METHODS: Patients with NF-1 aged 0-18 years were recruited from the Regional Genetic Family Register, following institutional review board approval. Magnetic resonance imaging data and clinical documents were reviewed with respect to clinical presentation, degree of ventriculomegaly, aetiological factors and management of AS and fourth ventricle outflow obstruction. RESULTS: 24 of the 233 paediatric patients seen within the NHS highly specialised service for complex NF1 were found to have AS or and fourth ventricle outflow obstruction. This included 13 males and 11 females with a mean age of 9 years 5 months (range 8 months - 17 years). The majority of patients with AS or fourth ventricle outflow obstruction presented with symptoms of raised intracranial pressure associated with ventriculomegaly and/or hydrocephalus (n = 18). However, in 25 % of patients, AS was an incidental finding on MRI and was observed both in the presence (n = 2) and absence (n = 4) of ventriculomegaly. In the majority of cases a single cause of AS was identified (n = 16), of which tectal plate thickening (n = 7) was most frequently observed. The remaining 8 patients had multiple causes of AS, in which tectal plate thickening (n = 7) and aqueductal webs (n = 5) were the most common observations. Surgery was performed on all patients with evidence of raised pressure (n = 8) by performing endoscopic third ventriculostomy (ETV) (n = 5) or ventriculoperitoneal (VP)-shunting (n = 3). Tectal plate thickening was most frequently observed in patients who underwent ETV (n = 3), followed by aqueductal web (n = 1) and T2-signal changes in the tectal plate (n = 1). Patients treated with VP-shunt had 4th ventricle outflow obstruction (n = 2) and a tectal plate tumour (n = 1). CONCLUSION: This study identifies that AS is more prevalent amongst the paediatric complex NF-1 population than previously reported, occurring in 10 % of cases. Our findings demonstrate that AS is most commonly symptomatic in presentation but can be asymptomatic in 25 % of paediatric complex NF1 patients. In this population, AS can occur both in the presence and absence of ventriculomegaly and therefore requires careful monitoring for development of hydrocephalus. In this study, over one third of patients (9 of 24 patients) with AS eventually required treatment.

Aqueductal Compression by Dilated Virchow-Robin Spaces in the Mesencephalic-Pontine Region Presenting with Symptoms Mimicking Normal Pressure Hydrocephalus: A Case Report and Review of Literature.

BACKGROUND: Dilatation of Virchow-Robin spaces (dVRS) have been described in the development of hydrocephalic syndromes. We report an unusual case of a type III dVRS presenting as a mimic of normal pressure hydrocephalus (NPH), due to distortion at the level of the cerebral aqueduct. CASE DESCRIPTION: A 59-year-old woman presented with mild traumatic brain injury and possible NPH, due to a history of progressive gait disturbance, recurrent falls, and cognitive decline over a year, in the context of ventriculomegaly. Detailed structural imaging of the brain revealed multiple dilated cystic lesions consistent with dVRS causing distortion at the level of the cerebral aqueduct. Cerebrospinal fluid examination was negative for infection. The patient was treated with endoscopic third ventriculostomy; at 12 months postoperatively, she demonstrated a sustained improvement in gait and stabilization of cognitive decline. CONCLUSIONS: This is an illustrative case of a subacute obstructive hydrocephalus due to a collection of periaqueductal dVRS, leading to an insidious clinical presentation mimicking NPH. We reviewed the literature for key clinical presentations and describe neuroanatomical considerations as well as primary treatment strategies. Various hydrocephalic syndromes may present with classic symptoms from Hakim's triad; such symptoms are not specific to idiopathic NPH. Both endoscopic third ventriculostomy and shunting may be efficacious. In our case, dVRS may serve as both a cause of and compensatory mechanism in a subacute obstructive hydrocephalus of unknown etiology. Our case highlights the need to understand the neuroanatomy of aberrant cerebrospinal fluid spaces in hydrocephalic syndromes. Further studies of dVRS would provide valuable insights into the pathogenesis of hydrocephalus.

A new frameshift mutation in L1CAM producing X-linked hydrocephalus.

BACKGROUND: X-linked hydrocephalus (XLH), characterized by mental retardation and bilateral adducted thumbs, often come out to be a genetic disorder of L1CAM. It codes the protein L1 cell adhesion molecule (L1CAM), playing a crucial role in the development of the nervous system. The objective of the study was to report a new disease-causing mutation site of L1CAM, and gain further insight into the pathophysiology of hydrocephalus. METHODS: We collect the samples of a couple and their second hydrocephalic fetus. Then, the whole-exome sequencing and in-depth mutation analysis were performed. RESULTS: The variant c.2491delG (p.V831fs), located in the exon 19 of L1CAM (chrX:153131214), could damage the L1CAM function by producing a frameshift in the translation of fibronectin type-III of L1CAM. CONCLUSION: We identified a novel disease-causing mutation in L1CAM for the first time, which further confirmed L1CAM as a gene underlying XLH cases.

Chronic Hydrocephalus Following Mumps Encephalitis: Neuropathological Correlates and Review.

Hydrocephalus is a rare and devastating complication of mumps encephalitis. The histopathological correlates of mumps infection in central nervous system tissues are not well-characterized. We present the case of a 54-year-old patient who suffered long-term neuropsychiatric sequelae and hydrocephalus as a consequence of a childhood mumps infection. Brain autopsy revealed significant dilation of the lateral and third ventricles. Aqueductal stenosis was not observed on premortem imaging or on gross examination. Histology revealed loss of ependymal epithelium throughout the aqueduct and ventricular system. Macrophage conglomerates were identified within the cerebral aqueduct at the level of the pons in addition to subjacent periaqueductal gliosis and scattered Rosenthal fibers. Together, these findings support primary ependymal injury as a pathophysiological mechanism in the development of chronic hydrocephalus following mumps infection. Finally, we review the existing literature and discuss potential mechanisms of disease.

SLC12A ion transporter mutations in sporadic and familial human congenital hydrocephalus.

BACKGROUND: Congenital hydrocephalus (CH) is a highly morbid disease that features enlarged brain ventricles and impaired cerebrospinal fluid homeostasis. Although early linkage or targeted sequencing studies in large multigenerational families have localized several genes for CH, the etiology of most CH cases remains unclear. Recent advances in whole exome sequencing (WES) have identified five new bona fide CH genes, implicating impaired regulation of neural stem cell fate in CH pathogenesis. Nonetheless, in the majority of CH cases, the pathological etiology remains unknown, suggesting more genes await discovery. METHODS: WES of family members of a sporadic and familial form of severe L1CAM mutation-negative CH associated with aqueductal stenosis was performed. Rare genetic variants were analyzed, prioritized, and validated. De novo copy number variants (CNVs) were identified using the XHMM algorithm and validated using qPCR. Xenopus oocyte experiments were performed to access mutation impact on protein function and expression. RESULTS: A novel inherited protein-damaging mutation (p.Pro605Leu) in SLC12A6, encoding the K+ -Cl- cotransporter KCC3, was identified in both affected members of multiplex kindred CHYD110. p.Pro605 is conserved in KCC3 orthologs and among all human KCC paralogs. The p.Pro605Leu mutation maps to the ion-transporting domain, and significantly reduces KCC3-dependent K+ transport. A novel de novo CNV (deletion) was identified in SLC12A7, encoding the KCC3 paralog and binding partner KCC4, in another family (CHYD130) with sporadic CH. CONCLUSION: These findings identify two novel, related genes associated with CH, and implicate genetically encoded impairments in ion transport for the first time in CH pathogenesis.

Familial Hydrocephalus and Dysgenesis of the Corpus Callosum Associated with Xp22.33 Duplication and Stenosis of the Aqueduct of Sylvius with X-Linked Recessive Inheritance Pattern.

INTRODUCTION: X-linked recessive mutations predominantly affect male fetuses with milder or no abnormalities in female siblings. Most reports show only one affected member in the family. We are reporting a family affected with hydrocephalus, stenosis of the aqueduct of Sylvius, dysgenesis of the corpus callosum, and Xp22.33 microduplication. CASE PRESENTATION: Eighteen-year-old patient was evaluated for her 2 pregnancies; the first was a male fetus with severe hydrocephalus and the second a female fetus with mild hydrocephalus. Postnatal MRI evaluation of the male neonate revealed stenosis of the aqueduct of Sylvius, dysgenesis of the corpus callosum, and severe hydrocephalus requiring ventriculoperitoneal shunt. Postnatal MRI evaluation of the female neonate revealed mild hydrocephalus, stenosis of the aqueduct of Sylvius, and mild dysgenesis of the corpus callosum. The female baby did not require surgical intervention. Genetic testing of the mother and the 2 children revealed a 439 Kb duplication of Xp22.33. DISCUSSION: This family demonstrates typical X-linked recessive heritability. X-inactivation is a compensatory mechanism that explains the mild symptoms of the female child and the severe symptoms of the male child. This familial case shows the importance of prenatal testing and genetic counseling and testing, including karyotype and chromosomal microarray.

Neuroendoscopic Aspiration of Blood Clots in the Cerebral Aqueduct and Third Ventricle During Posterior Fossa Surgery in the Prone Position.

BACKGROUND: During surgery in the posterior fossa in the prone position, blood can sometimes fill the surgical field, due both to the less efficient venous drainage compared to the sitting position and the horizontally positioned surgical field itself. In some cases, blood clots can wedge into the cerebral aqueduct and the third ventricle, and potentially cause acute hydrocephalus during the postoperative course. OBJECTIVE: To illustrate a technique that can be used in these cases: the use of a flexible scope introduced through the opened roof of the fourth ventricle with a freehand technique allows the navigation of the fourth ventricle, the cerebral aqueduct, and the third ventricle in order to explore the cerebrospinal fluid pathways and eventually aspirate blood clots and surgical debris. METHODS: We report on one patient affected by an ependymoma of the fourth ventricle, for whom we used a flexible neuroendoscope to explore and clear blood clots from the cerebral aqueduct and the third ventricle after the resection of the tumor in the prone position. Blood is aspirated with a syringe using the working channel of the scope as a sucker. RESULTS: A large blood clot that was lying on the roof of the third ventricle was aspirated, setting the ventricle completely free. Other clots were aspirated from the right foramen of Monro and from the optic recess. CONCLUSION: We describe this novel technique, which represents a safe and efficient way to clear the surgical field at the end of posterior fossa surgery in the prone position. The unusual endoscopic visual perspective and instrument maneuvers are easily handled with proper neuroendoscopic training.