The Genetic Basis of Hydrocephalus.

Studies of syndromic hydrocephalus have led to the identification of >100 causative genes. Even though this work has illuminated numerous pathways associated with hydrocephalus, it has also highlighted the fact that the genetics underlying this phenotype are more complex than anticipated originally. Mendelian forms of hydrocephalus account for a small fraction of the genetic burden, with clear evidence of background-dependent effects of alleles on penetrance and expressivity of driver mutations in key developmental and homeostatic pathways. Here, we synthesize the currently implicated genes and inheritance paradigms underlying hydrocephalus, grouping causal loci into functional modules that affect discrete, albeit partially overlapping, cellular processes. These in turn have the potential to both inform pathomechanism and assist in the rational molecular classification of a clinically heterogeneous phenotype. Finally, we discuss conceptual methods that can lead to enhanced gene identification and dissection of disease basis, knowledge that will potentially form a foundation for the design of future therapeutics.

A Review of Cerebrospinal Fluid Circulation and the Pathogenesis of Congenital Hydrocephalus.

The brain's ventricles are filled with a colorless fluid known as cerebrospinal fluid (CSF). When there is an excessive accumulation of CSF in the ventricles, it can result in high intracranial pressure, ventricular enlargement, and compression of the surrounding brain tissue, leading to potential damage. This condition is referred to as hydrocephalus. Hydrocephalus is classified into two categories: congenital and acquired. Congenital hydrocephalus (CH) poses significant challenges for affected children and their families, particularly in resource-poor countries. Recognizing the psychological and economic impacts is crucial for developing interventions and support systems that can help alleviate the distress and burden faced by these families. As our understanding of CSF production and circulation improves, we are gaining clearer insights into the causes of CH. In this article, we will summarize the current knowledge regarding CSF circulation pathways and the underlying causes of CH. The main causes of CH include abnormalities in the FoxJ1 pathway of ventricular cilia, dysfunctions in the choroid plexus transporter Na+-K+-2Cl- contransporter isoform 1, developmental abnormalities in the cerebral cortex, and structural abnormalities within the brain. Understanding the causes of CH is indeed crucial for advancing research and developing effective treatment strategies. In this review, we will summarize the findings from existing studies on the causes of CH and propose potential research directions to further our understanding of this condition.

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.

Giant tumefactive mesencephalothalamic Virchow-Robin space with triventricular hydrocephalus: a case-based systematic literature review.

BACKGROUND: The perivascular spaces of the brain are also known as Virchow-Robin spaces (VRSs). Dilated Virchow-Robin spaces in the brainstem are rare and mainly cause symptoms due to obstructive hydrocephalus, less frequently because of their size, mass effect, and impact on eloquent structures. CASE ILLUSTRATION: We present a patient with giant tumefactive VRS with hydrocephalus and neurological symptoms who was treated with endoscopic third ventriculostomy (ETV) followed by microscopic cyst fenestration. On the basis of this observation, we performed a thorough review of the literature to evaluate different treatment options. RESULTS: An 11-year-old girl presented with a headache for 3 months. The patient had a giant tumefactive mesencephalothalamic VRS with triventricular hydrocephalus. She was initially treated with endoscopic third ventriculostomy and multiple cyst fenestration. Symptomatic cyst regrowth required multiple cyst fenestrations via transcallosal transchoroidal (N = 2) and subtemporal approaches (N = 1) at the 2- and 4-year follow-ups. A literature review of these conditions allowed the detection of 12 cases (including our index case), and only 25% (3/12) of the patients underwent cyst fenestration 16.7% (2/12) required endoscopic fenestration and 8.3% (1/12) required microscopic fenestration. CONCLUSION: Giant mesencephalothalamic dVRSs are rare in the pediatric population. These patients are usually symptomatic due to obstructive hydrocephalus. Surgical options are endoscopic third ventriculostomy, ventricular shunt procedures, or direct cyst fenestration (microscopic or endoscopic). Close follow-up is mandatory owing to the risk of progression of the disease. Cyst fenestration resolves symptoms immediately, as it addresses both hydrocephalus and mass effects due to the cystic lesion in the same setting.

North American Fetal Therapy Network: Maternal Outcomes in Fetal Aqueductal Stenosis.

INTRODUCTION: Fetal aqueductal stenosis (AS) affects approximately 1:1,000 pregnancies. Obstruction of cerebral spinal fluid circulation occurs at the aqueduct of Sylvius, leading to progressive hydrocephalus and macrocephaly, which often necessitates cesarean section (CS). The purpose of this study was to describe maternal outcomes associated with fetal AS. METHODS: This study is conducted through the North American Fetal Therapy Network (NAFTNet). Subjects with a prenatal diagnosis of severe fetal central nervous system ventriculomegaly were recruited and followed longitudinally. Maternal events around the delivery of fetuses with AS were recorded and analyzed. RESULTS: Thirty-seven subjects with fetal AS confirmed by neonatal neuroimaging were analyzed. The average gestational age at delivery was 36.7 weeks. Overall, 86% were delivered by CS, and 62% of these were elective. Ninety-one percent of CSs were performed through a Pfannenstiel abdominal incision. A classical uterine incision was required in 13% of cesarean deliveries. The peripartum complication rate was 27%. CONCLUSION: Women carrying a fetus with AS were at risk for preterm birth, cesarean delivery, a classical uterine incision, and peripartum complications. These data highlight the maternal morbidity associated with fetal AS and the potential benefit of in utero therapy not only for neonatal outcomes but also for maternal outcomes.

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.

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.

Late-onset obstructive hydrocephalus associated with occipital encephalocele with large skull defect successfully treated by endoscopic third ventriculostomy.

BACKGROUND: Hydrocephalus is one of the most common presentations of occipital encephaloceles and usually develops within the first year of life. This case report presents a rare case of late-onset obstructive hydrocephalus associated with occipital encephalocele with an extraordinarily large occipital skull defect. CASE REPORT: At birth, a newborn girl presented with an absence of a vast amount of occipital cranium and skin and was diagnosed with occipital hydroencephalomeningocele. Under meticulous sterile management, the affected area was successfully epithelialized, and the patient was discharged without infectious complication. Despite an obstructed cerebral aqueduct, she grew without any signs of hydrocephalus until the age of 7 years. Her gait gradually worsened, and imaging tests at the age of 8 years revealed markedly enlarged lateral and third ventricles but not the fourth ventricle. Endoscopic third ventriculostomy successfully relieved her symptoms with improvement of hydrocephalus. CONCLUSION: This is the first case of late-onset obstructive hydrocephalus associated with an occipital encephalocele characterized by large-scale cranial bony defects. Although further investigation is required to elucidate the mechanism of hydrocephalus, this rare phenomenon should be noted during neurological and radiological follow-up.

Factors affecting endoscopic third ventriculostomy success in adults.

BACKGROUND: Endoscopic third ventriculostomy (ETV) is a standard treatment in hydrocephalus of certain aetiologies. The most widely used predictive model is the ETV success score. This is frequently used to predict outcomes following ETV in adult patients; however, this was a model developed in paediatric patients with often distinct aetiologies of hydrocephalus. The aim of this study was to assess the predictive value of the model and to identify factors that influence ETV outcomes in adults. METHODS: A retrospective study design was used to analyse consecutive patients who underwent ETV at a tertiary neurosurgical centre between 2012 and 2020. Observed ETV outcomes at 6 months were compared to pre-operative predicted ETV success scores. A multivariable Bayesian logistic regression analysis was used to determine the factors that best predicted ETV success and those factors that were redundant. RESULTS: A total of 136 patients were analysed during the 9-year study. Thirty-one patients underwent further cerebrospinal fluid diversion within 6 months. The overall ETV success rate was 77%. Observed ETV outcomes corresponded well with predicted outcomes using the ETV success score for the higher scores, but less well for lower scores. Location of obstruction at the aqueduct irrespective of aetiology was the best predictor of success with odds of 1.65 of success. Elective procedures were also associated with higher success compared to urgent ones, whereas age under 70, nature and location of obstructive lesion (other than aqueductal) did not influence ETV success. CONCLUSION: ETV was successful in three-quarters of adult patient with hydrocephalus within 6 months. Obstruction at the level of the aqueduct of any aetiology was a good predictor of ETV success. Clinicians should bear in mind that adult hydrocephalus responds differently to ETV compared to paediatric hydrocephalus, and more research is required to develop and validate an adult-specific predictive tool.

Open-aqueduct LOVA, LIAS, iNPH: a comparative clinical-radiological study exploring the "grey zone" between different forms of chronic adulthood hydrocephalus.

PURPOSE: The definition of chronic adult hydrocephalus encompasses different pathological entities with overlapping characteristics, including long-standing overt ventriculomegaly in adults (LOVA), late-onset idiopathic aqueductal stenosis (LIAS) and idiopathic normal pressure hydrocephalus (iNPH). The aim of our study was to identify preoperative clinical and radiological features peculiar of these diseases providing some pathophysiology inferences on these forms of hydrocephalus. METHODS: Clinical and radiological preoperative records, type of surgical treatment and clinical outcome of patients with chronic adult hydrocephalus who were surgically treated between 2013 and 2019 were retrospectively reviewed. Univariate and multivariate analyses were performed to evaluate the contribution of each variable to the differential diagnosis. RESULTS: In total, 105 patients were included: 18 with LOVA, 23 with LIAS and 64 with iNPH. On multivariate analysis, an enlarged cisterna magna and a more severe ventriculomegaly were associated with the diagnosis of LOVA, while an older age and DESH with iNPH. LIAS patients tend to have an higher prevalence of raised ICP symptoms. Based on that, a clinical and radiological scoring system was developed to distinguish between iNPH and no iNPH cases. A precise cut-off value with a sensitivity of 95.1% and a specificity of 90.6% was identified. CONCLUSIONS: LOVA, LIAS and iNPH are different forms of chronic adulthood hydrocephalus and present different and peculiar clinical and radiological features, with an impact on the treatment and outcome prediction. The implementation of a clinical-radiological score for differential diagnosis may help the differentiation. Further studies are warranted.

Prenatal diagnosis of rhombencephalosynapsis: neuroimaging features and severity of vermian anomaly.

OBJECTIVES: To describe the prenatal neuroimaging spectrum of rhombencephalosynapsis (RES) and criteria for its classification according to the severity of vermian anomaly. METHODS: In this multicenter retrospective study of fetuses with RES between 2002 and 2020, the medical records and brain ultrasound and magnetic resonance images were evaluated comprehensively to determine the severity of the vermian anomaly and the presence of associated brain findings. RES was classified, according to the pattern of vermian agenesis and the extent of the fusion of the hemispheres, as complete RES (complete absence of the vermis) or partial RES (further classified according to the part of the vermis that was missing and, consequently, the region of hemispheric fusion, as anterior, posterior, severe or mixed RES). Findings were compared between cases with complete and those with partial RES. RESULTS: Included in the study were 62 fetuses with a gestational age ranging between 12 and 37 weeks. Most had complete absence of the vermis (complete RES, 77.4% of cases), a 'round-shaped' cerebellum on axial views (72.6%) and a transverse cerebellar diameter (TCD) < 3rd centile (87.1%). Among the 22.6% of cases with partial RES, 6.5% were classified as severe partial, 6.5% as partial anterior, 8.1% as partial mixed and 1.6% as partial posterior. Half of these cases presented with normal or nearly normal cerebellar morphology and 28.5% had a TCD within the normal limits. Infratentorially, the fourth ventricle was abnormal in 88.7% of cases overall, and anomalies of the midbrain and pons were frequent (93.5% and 77.4%, respectively). Ventriculomegaly was observed in 80.6% of all cases, being more severe in cases with complete RES than in those with partial RES, with high rates of parenchymal and septal disruption. CONCLUSIONS: This study provides prenatal neuroimaging criteria for the diagnosis and classification of RES, and identification of related features, using ultrasound and magnetic resonance imaging. According to our findings, a diagnosis of RES should be considered in fetuses with a small TCD (severe cerebellar hypoplasia) and/or a round-shaped cerebellum on axial views, during the second or third trimester, especially when associated with ventriculomegaly. Partial RES is more common than previously thought, but presents an extreme diagnostic challenge, especially in cases with normal or nearly-normal cerebellar morphobiometric features. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Porencephalic cyst after endoscopic third ventriculostomy and Ommaya reservoir placement: case report and review of the literature.

BACKGROUND: A 13-year-old female patient was diagnosed with a tectal glioma (TG), a subgroup of astrocytoma that can result in obstructive hydrocephalus secondary to aqueductal stenosis. Endoscopic third ventriculostomy (ETV) is used to treat this type of hydrocephalus with a good success rate. Our institution performs ETV and Ommaya reservoir (OR) placement in these cases. The OR allows measurement of intracranial pressure (ICP) and cerebrospinal fluid (CSF) access and a method for performing ventricular dye studies to evaluate third ventricular stoma (TVS) patency. In this case, a porencephalic cyst (PC) developed around the OR's ventricular catheter (OVC) two and a half months after surgery. CONCLUSION: The PC is thought to have developed in association with TVS stoma closure and resolved after ETV revision.

Endoscopic aqueductoplasty and stenting in the treatment of isolated fourth ventricle in children: 20-year institutional experience.

BACKGROUND: Endoscopic aqueductoplasty with aqueductal stenting is an effective surgical procedure for the treatment of isolated fourth ventricle (IFV). Due to the rarity of the underlying pathology, it can be considered a rare procedure that can be performed with different surgical techniques and approaches. OBJECTIVES: To assess long-term functioning of permanent aqueductal stents implanted in children affected by hydrocephalus and IFV and to describe some variations of the same procedure. METHODS: We reviewed retrospectively all the patients presenting at our institution in the years 1999-2019 for symptoms of isolated fourth ventricle who underwent a surgical procedure of endoscopic aqueductoplasty and/or aqueductal stent. Surgical reports, radiological images, and surgical videos were retrospectively analyzed. RESULTS: Thirty-three patients with symptomatic isolated fourth ventricle (IFV) underwent fifty (50) neuroendoscopic procedures in the period observed. The median age of the patients at the time of first surgery was 7 months, with 22 premature babies. In twenty-nine patients (87.8%), a precoronal approach was performed, while four patients received a suboccipital burr hole. Ten patients were never reoperated since. Twenty-three patients underwent further surgeries: a new aqueductoplasty with aqueductal stent was performed in 13 cases. The remaining 10 patients required a combination of other procedures for management of hydrocephalus. Long-term follow-up showed a permanent stent functioning rate of 87% at 2 years and 73% at 4 years, remaining stable afterwards at very long term (20 years). CONCLUSION: Endoscopic aqueductoplasty and stenting is a reliable procedure in the long-term management of isolated fourth ventricle.

Longstanding overt ventriculomegaly in adults (LOVA) with patent aqueduct: surgical outcome and etiopathogenesis of a possibly distinct form of chronic hydrocephalus.

PURPOSE: Longstanding overt ventriculomegaly in adults (LOVA) represents a form of chronic adulthood hydrocephalus with symptomatic manifestation in late adulthood. Based on the patency of the aqueduct, two different subcohorts of LOVA can be distinguished. Surgical treatments of this condition are also debated. Therefore, we analyzed preoperative characteristics and clinical outcome after different surgical treatments in a subgroup of LOVA patients with a patent aqueduct. METHODS: Eighteen LOVA patients with a patent aqueduct consecutively treated at our institution between July 2013 and December 2019 were analyzed for this study. Median age was 70 years. Preoperative radiological and clinical features, surgical procedures (ventriculo-peritoneal shunt or endoscopic third ventriculostomy), and outcomes were collected. Successful outcome was qualitatively defined as an improvement or a halt of progression of the presenting symptoms at follow-up, and quantitatively by changes in mRS and iNPHGS scales. RESULTS: Twelve patients underwent an ETV as a primary treatment, while 6 underwent VPS. A total of 22.2% of them were lost to follow-up. Median follow-up time was 38 months. Six patients (66.7%) in the ETV cohort achieved a successful outcome after treatment, with a complication rate of 11.1%. Two patients underwent rescue VPS after ETV failure with a good outcome. Four patients (100%) underwent primary VPS and achieved a satisfactory outcome after treatment, with a reported complications rate of 25%. CONCLUSION: LOVA with patent aqueduct represents, in our opinion, a distinct clinical form of chronic hydrocephalus. For this subgroup, as well as for other forms of LOVA, ETV remains an acceptable first-line treatment option considering the good results, and the low complication rate, obtained in those patients and the hypothesis that hydrocephalus is due to an "intracisternal" obstruction.

Endoscopic Third Ventriculostomy in Infants Less than One Year of Age: A Short Series of 14 Cases.

BACKGROUND: Endoscopic third ventriculostomy (ETV) is currently considered as an alternative to cerebrospinal fluid (CSF) shunt systems in the treatment of obstructive hydrocephalus. This procedure allows the CSF to drain in the basal cisterns and reabsorbed by arachnoid granulations, and avoiding implantation of exogenous material. AIMS AND OBJECTIVES: The purpose of this study was to assess the success rate of ETV in infants less than 1 year of age with congenital noncommunicating hydrocephalus. MATERIAL AND METHODS: This study was a 2-year prospective study from August 2017 to July 2019. ETVs were performed in 14 patients younger than 1 year with diagnosis of noncommunicating hydrocephalous. A failure was defined as the need for shunt implantation after ETV. Phase-contrast MRI of the brain was done after 6 months to see patency of ETV fenestration and CSF flow through ventriculostomy. RESULTS: ETV was tried in 18 patients and successfully performed in 14 patients. Out of the 14 patients, shunt implantation after ETV was performed in 3 patients (failed ETV). In the successful cases, etiology was idiopathic aqueductal stenosis in 8, shunt complications in 2, and 1 case was a follow-up case of occipital encephalocele; the mean age was 7.7 months (range 3-12). In the 3 failed cases, etiology was aqueductal stenosis, mean age was 7.6 months (range 3-11). In all ETVs, failed patients MPVP shunting was done. Follow-up of nonshunted patients was done from 6 to 24 months (mean 15 months). There was no mortality or permanent morbidity noted following ETV. CONCLUSION: ETV is a good surgical procedure for less than 1-year-old children.

Long-Term Outcomes of Patients with Hydrocephalus Secondary to Tectal Plate Glioma versus Idiopathic Aqueductal Stenosis: Results from a Single Center.

INTRODUCTION: Tectal plate gliomas (TPG) constitute a distinct entity of benign tumors of the brain stem which show an indolent clinical course. Adequate treatment of secondary hydrocephalus is undoubtedly a major factor in the outcome. However, little is known about to what degree the tumor itself determines the long-term outcome of these patients. METHODS: We retrospectively analyzed and compared the clinical and radiological data of 16 pediatric TPG patients with data of 12 pediatric idiopathic aqueductal stenosis (IAS) patients treated in our center from 1988 to 2018. For both groups, we assessed the long-term outcome in terms of hydrocephalus management, and for the TPG group, we assessed tumor growth during follow-up. In a separate prospective part of the study, we performed a neuropsychological evaluation in a subgroup of patients using a standardized testing battery, covering intelligence, learning, memory, executive functions, and an inventory on depression. RESULTS: In the TPG group, the mean clinical and radiological follow-up was 84 and 70 months, respectively. On average, the maximum diameter of the tumor increased by 11% (p = 0.031) and the estimated tumor volume with 35% (p = 0.026) on radiological follow-up. The fronto-occipital horn ratio (FOHR) decreased by 23% on average after treatment. In the IAS group, the mean clinical and radiological follow-up was 117 and 85 months, respectively. In this group, the FOHR decreased by 21% on average. Neurocognitive testing revealed significant higher scores in the TPG group on global intelligence (TPG = 109, IAS = 85.5, U = 3, p < 0.01, z = -2.71), performance (TPG= 100, IAS = 85, U = 7, p = 0.03, z = -2.2), and verbal intelligence (TPG = 122, IAS = 91.5, U = 2, p < 0.00, z = -2.87) as well as working memory (TPG = 109.5, IAS = 77, U = 0.5, p = 0.01, z = -2.46). CONCLUSION: Our results suggest that the long-term outcome in TPG patients is acceptable and that cognition is substantially better preserved than in patients with IAS. This puts the idea of a significant contribution of the tumoral mass to disease outcome on the long term in question. Adequate and prompt management of hydrocephalus is the most important factor in long-term cognitive outcome.

A comparison between flow-regulated and adjustable valves used in hydrocephalus during infancy.

INTRODUCTION: Ventriculoperitoneal shunt insertion during the neonatal period and early infancy is associated with a high rate of shunt failure when compared to the adult population. Furthermore, the function of flow-regulated valves and differential pressure valves may be different in neonatal hydrocephalus. METHODS: A retrospective case series of all primary shunt procedures carried out during or immediately following the neonatal period, from August 2011 to February 2018 at Sheffield Children's Hospital. The total sample size was 55. This included 34 patients with adjustable valves (Miethke ProGav) and 21 with flow-regulated valves (Orbis-Sigma); however, only 53 had adequate follow-up. RESULTS: The overall 1 year shunt survival was 34% (18/53), and there was no significant difference depending on which shunt valve was implanted. The primary shunt infection rate was 11% (6/53) with S. aureus being the most common causative organism. During the first year of life, clinical signs of shunt overdrainage were seen more frequently in patients with adjustable valves than in those with flow-regulated valves (59% [19/32] versus 24% [5/21], p = 0.02). Furthermore, 2 patients in the adjustable valve group developed sagittal craniosynostosis secondary to shunt overdrainage. CONCLUSION: Shunt failure is high when inserted during or immediately following the neonatal period. Overdrainage may be less common in patients with flow-regulated valves. However, if overdrainage is observed, adjusting the setting of a differential pressure valve can effectively treat the overdrainage without the need for invasive shunt revision surgery.

A case of developing obstructive hydrocephalus following aqueductal stenosis caused by developmental venous anomalies.

Developmental venous anomalies (DVAs), previously also known as venous angiomas, are variations of normal trans-medullary veins draining from white and gray matter. DVAs are usually asymptomatic and mostly discovered incidentally on brain imaging. However, some studies have reported symptomatic cases associated with DVAs. In this report, we report an extremely rare case of a 14-month-old boy with obstructive hydrocephalus following aqueductal stenosis caused by developmental venous anomalies. At the age of 14 months, his head circumference exceeded + 2SD significantly. Brain magnetic resonance imaging (MRI) showed triventriculomegaly and dilated collector vein coursing through the Sylvian aqueduct, causing aqueductal stenosis. Endoscopic third ventriculostomy (ETV) was successfully performed. During the procedure, a dilated collector vein was confirmed obstructing the Sylvian aqueduct. Postoperative cine MRI showed good flow signal through the opening and improvement of hydrocephalus was noted. Obstructive hydrocephalus following aqueductal stenosis caused by DVAs is very rare; nonetheless, it can be considered as a causal differential diagnosis for hydrocephalus. Whether ETV should be chosen, as the technique for diversion of cerebrospinal fluid (CSF) flow, remains controversial. This case report showed that ETV was effective and safe.

Endoscopic management of pineal cyst-associated aqueductal stenosis.

OBJECT: The purpose of this study was to evaluate whether endoscopic third ventriculostomy (ETV) and endoscopic cyst fenestration are effective minimally invasive alternatives to a craniotomy with cyst resection for the treatment of symptomatic pineal cyst-associated aqueductal stenosis. METHODS: Sixteen patients with symptomatic pineal cysts were operatively managed endoscopically and these cases were retrospectively reviewed. There were 12 females and 4 males. The median age at the time of surgery was 31 years (range 3 to 62 years). RESULTS: All patients presented with symptoms and imaging consistent with elevated intracranial pressure. The median maximum cyst diameter was 15 mm (range 10 mm to 27 mm). In all cases, there was mass effect on the tectum that resulted in effacement of the cerebral aqueduct and ventriculomegaly was present in 38% of cases. ETV was performed in 15 patients. Cyst fenestration was performed in 2 patients, one of which also had an ETV. Resolution of symptoms was achieved in 81% of patients with a median follow-up of 13 months. CONCLUSION: This study showed that ETV is effective for symptomatic pineal cyst-associated aqueductal stenosis. Patients can be symptomatic without overt ventriculomegaly and normal ventricular volume does not preclude safe endoscopic management. Endoscopic cyst fenestration is recommended if a Perinaud syndrome is present or if ETV is not feasible.

Thanatophoric dysplasia type 1 with tectal plate dysplasia and aqueductal stenosis.

INTRODUCTION: Skeletal dysplasias are a heterogeneous group of disorders comprising of more than 300 entities, many of which manifest in the prenatal period, emphasizing the importance of accurate prenatal diagnosis. Detection of a lethal skeletal dysplasia via prenatal ultrasound is often straightforward. However, establishing the specific diagnosis and detailed evaluation of intracranial anomalies are often challenging. Fetal magnetic resonance imaging (MRI) is superior to ultrasound in the detection of abnormal sulcation pattern, corpus callosal agenesis, and posterior fossa anomalies. Hence, it has the potential of delineating neuroimaging features that may not be fully elucidated by ultrasound. The objective of this article is to describe an unusual case of thanatophoric dysplasia (TD) with dysplastic tectal plate and resultant aqueductal stenosis diagnosed on fetal MRI. To the best of our knowledge, this has never been reported before in the literature. A comprehensive review of literature pertaining to TD-associated CNS abnormalities will also be included. CONCLUSIONS: Our reported case adds to the current limited knowledge of this rare entity and emphasizes the crucial role of fetal MRI in expanding the neuroimaging phenotypes of TD.