Age-specific global epidemiology of hydrocephalus: Systematic review, metanalysis and global birth surveillance. PLoS One. 2018;13:e0204926. [PMID: 30273390 PMCID: PMC6166961 DOI: 10.1371/journal.pone.0204926]

Impact of aquaporin-4 and CD11c + microglia in the development of ependymal cells in the aqueduct: inferences to hydrocephalus

AQP4 is expressed in the endfeet membranes of subpial and perivascular astrocytes and in the ependymal cells that line the ventricular system. The sporadic appearance of obstructive congenital hydrocephalus (OCHC) has been observed in the offspring of AQP4-/- mice (KO) due to stenosis of Silvio's aqueduct. Here, we explore whether the lack of AQP4 expression leads to abnormal development of ependymal cells in the aqueduct of mice. We compared periaqueductal samples from wild-type and KO mice. The microarray-based transcriptome analysis reflected a large number of genes with differential expression (809). Gene sets (GS) associated with ependymal development, ciliary function and the immune system were specially modified qPCR confirmed reduced expression in the KO mice genes: (i) coding for transcription factors for ependymal differentiation (Rfx4 and FoxJ1), (ii) involved in the constitution of the central apparatus of the axoneme (Spag16 and Hydin), (iii) associated with ciliary assembly (Cfap43, Cfap69 and Ccdc170), and (iv) involved in intercellular junction complexes of the ependyma (Cdhr4). By contrast, genes such as Spp1, Gpnmb, Itgax, and Cd68, associated with a Cd11c-positive microglial population, were overexpressed in the KO mice. Electron microscopy and Immunofluorescence of vimentin and γ-tubulin revealed a disorganized ependyma in the KO mice, with changes in the intercellular complex union, unevenly orientated cilia, and variations in the planar cell polarity of the apical membrane. These structural alterations translate into reduced cilia beat frequency, which might alter cerebrospinal fluid movement. The presence of CD11c + microglia cells in the periaqueductal zone of mice during the first postnatal week is a novel finding. In AQP4-/- mice, these cells remain present around the aqueduct for an extended period, showing peak expression at P11. We propose that these cells play an important role in the normal development of the ependyma and that their overexpression in KO mice is crucial to reduce ependyma abnormalities that could otherwise contribute to the development of obstructive hydrocephalus.

Flexible low-profile external ventricular drain catheter for real-time brain monitoring

External ventricular drainage is one of the most common neurosurgical procedures in the world for acute hydrocephalus, which must be performed carefully by a neurosurgeon. Although various neuromonitoring external ventricular drain (EVD) catheters have been utilized, they still suffer from rigidity and bulkiness to mitigate post-EVD placement trauma. Here, we introduce a flexible and low-profile smart EVD catheter using a class of technologies with sensitive electrical materials, seamless integration, and flexible mechanics, which serves as a highly soft and minimally invasive device to monitor electrical brain signals. This device reliably captures biopotentials in real time while exhibiting remarkable flexibility and reliability. The seamless integration of its sensory system promises a minimally invasive EVD placement on brain tissue. This work validates the device's distinct characteristics and performances through in vitro experiments and computational analysis. Collectively, this device's exceptional patient- and user-friendly attributes highlight its potential as one of the most practical EVD catheters.

Falciform technique in laparoscopic revision of distal catheter obstruction: an evaluation

Background

Ventriculoperitoneal (VP) shunting is a cornerstone treatment for hydrocephalus, a condition characterized by the abnormal accumulation of cerebrospinal fluid in the ventricles of the brain. Despite its efficacy, this procedure is associated with various complications, among which distal catheter obstruction poses significant challenges. This study aimed to evaluate the effectiveness of the 'falciform technique' in laparoscopic revision of distal catheter obstructions, offering a novel approach to mitigate this prevalent issue.

Materials and methods

This study retrospectively analyzed 28 patients with VP shunt distal catheter obstructions who underwent laparoscopy-assisted shunt revision between January 2016 and June 2022. All of these were done using the 'falciform technique' with the fixation of the distal catheter to the falciform ligament in supra-hepatic space.

Results

The most common etiology of primary shunt surgery was hydrocephalus, followed by intracranial hemorrhage (42.9%) and traumatic brain injury (32.1%). Normal pressure hydrocephalus occurs in 14.3% of cases. Fifteen patients (53.6%) required revision surgery within 1 year of index surgery. Thirteen patients (46.4%) underwent revision surgery more than 1 year after the index surgery, either as a first revision or subsequent revision. The average surgery time was 32.1±14.7 min and hospital stay was 4.2±1.8 days. After a mean follow-up period of at 20.3±8.7 months, except for three patients who died from other causes (two patients due to pneumonia and one due to exhaustion), there were no shunt-related complications in the remaining 25 patients.

Conclusions

Laparoscopy with the application of 'falciform technique' is a safe and highly effective method in distal catheter obstruction revision following VP shunt.

Cerebrospinal Fluid Shunt Reinfection and Malfunction in Ecuadorian Children with Different Reshunting Criteria After Infection. "Is It Just One Shunt After Another?"

OBJECTIVE

There is no firm evidence regarding cerebrospinal fluid (CSF) shunt reimplantation after infection in the pediatric population. The purpose of this study was to compare different criteria and analyze new shunt failure.

METHODS

A cross-sectional retrospective multicenter study was performed over 6 years to study patients and each infected shunt at diagnosis, reimplantation, and after reimplantation. The patients were divided into 2 groups: group 1 (G1), reimplantation after negative serial CSF cultures during antibiotic treatment; group 2 (G2), reimplantation after negative serial pancultures after completion of antibiotics. The differences were measured with Mann-Whitney and Χ2 tests; multivariate analysis and associations were calculated using odds ratios (ORs) based on logistic regression.

RESULTS

There were 137 shunt infection events in 110 patients: 28 events in G1 and 109 in G2. Significant differences were observed in the diagnosis and reimplantation. Reimplantation dysfunction in G1 was 16 (55.17%) versus 30 (27.78%) in G2 (P = 0.006). The risk of shunt malfunction after reimplantation increased for G1 reimplantation criteria (P = 0.018; OR, 3.34; confidence interval [CI], 1.23-9.05): pleocytosis at diagnosis >17 cells (P = 0.036; OR, 2.41; CI, 1.06-5.47), CSF proteins at diagnosis >182 mg/dL (P = 0.049; OR, 2.21; CI, 1.00-4.89).

CONCLUSIONS

G2 reimplantation criteria were related to improved pleocytosis, CSF proteins, and blood neutrophils compared with G1. Mechanical and infectious dysfunction of the new shunt was 3 times more prevalent in G1 than in G2, considering the differences between the groups at diagnosis. Increased parameters of infection at diagnosis were associated with future malfunction more than parameters before reimplantation in both groups.

G, Gunasekaran A, Chandar V. Comparison of Optic Nerve Sheath Diameter (ONSD) Measurements Obtained from USG Before and After Placement of Ventriculoperitoneal Shunt in Obstructive Hydrocephalus as a Surrogate Marker for Adequacy of Shunt Function: A Prospective Observational Study

Introduction  Optic nerve sheath diameter (ONSD) measured using ultrasonography has been widely used as a surrogate marker of elevated intracranial pressure. However, literature is sparse on the correlation between ONSD and ventriculoperitoneal (VP) shunt function, especially in adults with hydrocephalus. Our study was designed to assess the correlation between ONSD measured using ultrasonography before and 12 hours after VP shunt placement and the success of VP shunt placement assessed using computed tomography (CT) of the brain. Materials and Methods  Fifty-one patients between 16 and 60 years of age, with obstructive hydrocephalus scheduled for VP shunt surgery were included in this prospective, observational study. ONSD measurements were obtained from both eyes prior to induction of anesthesia, immediately after the surgery, and at 6, 12, and 24 hours after the surgery. An average of three readings was obtained from each eye. Cerebrospinal fluid (CSF) opening pressure was noted after entry into the lateral ventricle. Noncontrast CT (NCCT) brain was obtained 12 hours after the surgery and was interpreted by the same neurosurgeon for signs of successful VP shunt placement. Results  There was a significant reduction in ONSD in the postoperative period compared to ONSD measured preoperatively. The average ONSD (mean ± standard deviation) measured prior to induction of anesthesia, immediately after the surgery, and at 6, 12, and 24 hours after the surgery was 5.71 ± 0.95, 5.20 ± 0.84, 5.06 ± 0.79, 4.90 ± 0.79, and 4.76 ± 0.75 mm, respectively. The mean CSF opening pressure was 19.6 ± 6.9 mm Hg. Postoperative NCCT brain revealed misplacement of the shunt tip in only one patient. Conclusion  ONSD measured using ultrasonography may be used as a reliable indicator of VP shunt function in adults with obstructive hydrocephalus.

Structural and functional connectivity in hydrocephalus: a scoping review

Optimizing the treatment of hydrocephalus remains a major challenge in adult and pediatric neurosurgery. Currently, clinical treatment relies heavily on anatomic imaging of ventricular size and clinical presentation. The emergence of functional and structural brain connectivity imaging has provided the basis for a new paradigm in the management of hydrocephalus. Here we review the pertinent advances in this field. Following PRISMA-ScR guidelines for scoping reviews, we searched PubMed for relevant literature from 1994 to April 2023 using hydrocephalus and MRI-related terms. Included articles reported original MRI data on human subjects with hydrocephalus, while excluding non-English or pre-1994 publications that didn't match the study framework. The review identified 44 studies that investigated functional and/or structural connectivity using various MRI techniques across different hydrocephalus populations. While there is significant heterogeneity in imaging technology and connectivity analysis, there is broad consensus in the literature that 1) hydrocephalus is associated with disruption of functional and structural connectivity, 2) this disruption in cerebral connectivity can be further associated with neurologic compromise 3) timely treatment of hydrocephalus restores both cerebral connectivity and neurologic compromise. The robustness and consistency of these findings vary as a function of patient age, hydrocephalus etiology, and the connectivity region of interest studied. Functional and structural brain connectivity imaging shows potential as an imaging biomarker that may facilitate optimization of hydrocephalus treatment. Future research should focus on standardizing regions of interest as well as identifying connectivity analysis most pertinent to clinical outcome.

Influence of age on the relation between body position and noninvasively acquired intracranial pulse waves

The capacitive measurement of the head's dielectric properties has been recently proposed as a noninvasive method for deriving surrogates of craniospinal compliance (CC), a parameter used in the evaluation of space-occupying neurological disorders. With the higher prevalence of such disorders in the older compared to the younger population, data on the head's dielectric properties of older healthy individuals would be of particularly high value before assessing pathologic changes. However, so far only measurements on young volunteers (< 30 years) were reported. In the present study, we have investigated the capacitively obtained electric signal known as W in older healthy individuals. Thirteen healthy subjects aged > 60 years were included in the study. W was acquired in the resting state (supine horizontal position), and during head-up and head-down tilting. AMP, the peak-to-valley amplitude of W related to cardiac action, was extracted from W. AMP was higher in this older cohort compared to the previously investigated younger one (0°: 5965 ± 1677 arbitrary units (au)). During head-up tilting, AMP decreased (+ 60°: 4446 ± 1620 au, P < 0.001), whereas it increased during head-down tilting (- 30°: 7600 ± 2123 au, P < 0.001), as also observed in the younger cohort. Our observation that AMP, a metric potentially reflective of CC, is higher in the older compared to the younger cohort aligns with the expected decrease of CC with age. Furthermore, the robustness of AMP is reinforced by the consistent relative changes observed during tilt testing in both cohorts.

Classification of Chronic Hydrocephalus in Adults: A Systematic Review and Analysis

BACKGROUND

Chronic hydrocephalus in adults (CHiA) includes all nonacute forms of hydrocephalus occurring in adulthood. It covers a spectrum of disorders. Some of these have relatively agreed on definitions, while others are less well characterized. The existing medical classification systems lack adequate structure and are neither clinically oriented nor easy to use, which severely hampers research and clinical care efforts.

METHODS

A systematic literature review and data analysis were performed, focusing on the terms "adult hydrocephalus" and "classification," using the PubMed, Scopus, and Cochrane Library databases. Data on terminology, definitions, patient demographics, symptom duration, and clinical presentations were extracted, analyzed, and compiled. A Delphi process was followed to define CHiA disorders.

RESULTS

A total of 33 studies collectively used 48 terms to define various CHiA disorders. Different terms were used to describe similar conditions. CHiA disorders were found to be clustered into 7 distinctive clinical entities based on the clinical characteristics.

CONCLUSIONS

An evidence-based new clinical classification for CHiA is suggested. Our review identified gaps in knowledge and areas for further research.

Do P-glycoprotein Medications Alter the Risk of Ventriculoperitoneal Shunt in Adults with Hydrocephalus?

Hydrocephalus is a disorder caused by excess fluid accumulation in the brain and results in brain damage with consequent cognitive and physical problems. This condition has no cure; the only treatment is brain surgery. Experimental data indicate that P-glycoprotein (P-gp) plays a crucial role in the pathogenesis of hydrocephalus due to its function in clearing macromolecules from the brain. Numerous medications frequently used are classified as P-gp inducers or inhibitors, and comprehending their effects may aid in attaining improved patient outcomes. Therefore, in this single-center retrospective study, we examined the risk of the need for ventriculoperitoneal shunt placement over 10 years among 4588 adult patients with hydrocephalus not exposed to any P-gp inhibitors/inducers or exclusively exposed to either P-gp inhibitors or inducers. Our analysis shows that patients exposed to P-gp inhibitors had a 3.2 times higher risk of requiring ventriculoperitoneal shunt surgery (P < .0001). In contrast, the relative risk was not significantly affected (P = .07) among those exposed to P-gp inducers. Our findings indicate the need for caution when prescribing P-gp inhibitors to patients with hydrocephalus. Additional studies using larger cohorts are required to confirm whether P-gp inducers in patients with hydrocephalus can mitigate the risk of ventriculoperitoneal shunt.

Engineering innovations in medicine and biology: Revolutionizing patient care through mechanical solutions

The overlap between mechanical engineering and medicine is expanding more and more over the years. Engineers are now using their expertise to design and create functional biomaterials and are continually collaborating with physicians to improve patient health. In this review, we explore the state of scientific knowledge in the areas of biomaterials, biomechanics, nanomechanics, and computational fluid dynamics (CFD) in relation to the pharmaceutical and medical industry. Focusing on current research and breakthroughs, we provide an overview of how these fields are being used to create new technologies for medical treatments of human patients. Barriers and constraints in these fields, as well as ways to overcome them, are also described in this review. Finally, the potential for future advances in biomaterials to fundamentally change the current approach to medicine and biology is also discussed.

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.

Congenital Pediatric Hydrocephalus in the Brazilian Public Health System: The Reality of a Middle-Income Country in the Past 13 Years

BACKGROUND

Congenital hydrocephalus is a significant challenge in neurosurgery, particularly in resource-limited settings. This study focuses on the congenital hydrocephalus in Brazil, a developing country, over the past 13 years.

METHODS

This study is a retrospective analysis of congenital hydrocephalus treatment and outcomes using data records on DATASUS from January 2008 to July 2021. Demographics, cost of hospitalizations, amount paid to professionals, mortality, and mean length of stay (LOS) were analyzed. Statistical analysis was conducted to determine significant associations between these indicators and pediatric hydrocephalus.

RESULTS

DATASUS recorded 8493 cases of congenital hydrocephalus in the studied period, with a prevalence of 24.28 per 100,000 newborns, mostly linked to spina bifida. Congenital hydrocephalus caused 60.83 ± 13.98 neonatal deaths per year, with the highest rate among 32-36 weeks gestational age. Acquired hydrocephalus led to 1063 infant deaths, whereas congenital hydrocephalus resulted in 3122 deaths, with no clear trend by the years. White infants had the highest mortality. A total of 33,184 shunt procedures were performed, with an average cost of $715.37 per procedure. The mortality model showed no significant effects of cost or professionals' salary, but a significant effect of LOS on hospitalization costs was observed.

CONCLUSIONS

Pediatric hydrocephalus in Brazil's public health system is a significant burden. Congenital hydrocephalus prevalence and mortality emphasize the need for early diagnosis and treatment. Early diagnosis, prenatal care, and adequate resources are crucial. This study offers insights into congenital hydrocephalus, highlighting challenges and future directions for improved care.

Racial and ethnic differences in infant survival for hydrocephaly-Texas, 1999-2017

BACKGROUND

Congenital hydrocephaly, an abnormal accumulation of fluid within the ventricular spaces at birth, can cause disability or death if untreated. Limited information is available about survival of infants born with hydrocephaly in Texas. Therefore, the purpose of the study was to calculate survival estimates among infants born with hydrocephaly without spina bifida in Texas.

METHODS

A cohort of live-born infants delivered during 1999-2017 with congenital hydrocephaly without spina bifida was identified from the Texas Birth Defects Registry. Deaths within 1 year of delivery were identified using vital and medical records. One-year infant survival estimates were generated for multiple descriptive characteristics using the Kaplan-Meier method. Crude hazard ratios (HRs) for one-year survival among infants with congenital hydrocephaly by maternal and infant characteristics and adjusted HRs for maternal race and ethnicity were estimated using Cox proportional hazard models.

RESULTS

Among 5709 infants born with congenital hydrocephaly without spina bifida, 4681 (82%) survived the first year. The following characteristics were associated with infant survival: maternal race and ethnicity, clinical classification (e.g., chromosomal or syndromic), preterm birth, birth weight, birth year, and maternal education. In the multivariable Cox proportional hazards model, differences in survival were observed by maternal race and ethnicity after adjustment for other maternal and infant characteristics. Infants of non-Hispanic Black (HR: 1.28, 95% CI: 1.04-1.58) and Hispanic (HR: 1.31, 95% CI: 1.12-1.54) women had increased risk for mortality, compared with infants of non-Hispanic White women.

CONCLUSIONS

This study showed infant survival among a Texas cohort differed by maternal race and ethnicity, clinical classification, gestational age, birth weight, birth year, and maternal education in infants with congenital hydrocephaly without spina bifida. Findings confirm that mortality continues to be common among infants with hydrocephaly without spina bifida. Additional research is needed to identify other risk factors of mortality risk.

Association between altered white matter networks and post operative ventricle volume in shunt-treated pediatric hydrocephalus

OBJECTIVE

The objective of this study was to use probabilistic tractography in combination with white matter microstructure metrics to characterize differences in white matter networks between shunt-treated pediatric hydrocephalus patients relative to healthy controls. We were also able to explore the relationship between these white matter networks and postoperative ventricle volume.

METHODS

Network-based statistics was used in combination with whole-brain probabilistic tractography to determine dysregulated white matter networks in a sample of patients with pediatric hydrocephalus (n = 8), relative to controls (n = 36). Metrics such as streamline count (SC), as well as the mean of the fractional anisotropy along a tract, axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) were assessed. In networks that were found to be significantly different for patients with hydrocephalus, tracts were evaluated to assess their relationship with postoperative lateral ventricle volume.

RESULTS

Patients with pediatric hydrocephalus had various networks that were either upregulated or downregulated relative to controls across all white matter measures. Predominately, network dysregulation occurred in tracts involving structures located outside of the frontal lobe. Furthermore tracts with values suggesting decreased white matter integrity were not only found between subcortical structures, but also cortical structures. While there were various tracts with white matter metrics that were initially predicted by lateral ventricle volume, only two tracts remained significant following multiple comparisons.

CONCLUSIONS

This cross-sectional study in pediatric patients with hydrocephalus and healthy controls demonstrated using whole-brain probabilistic tractography that there are various networks with dysregulated white matter integrity in hydrocephalus patients relative to controls. These dysregulated networks have tracts connecting structures throughout the brain, and the regions were predominately located centrally and posteriorly. Postoperative ventricle volume did not predict the white matter integrity of many tracts. Future studies with larger sample sizes are needed to further understand these results.

Polyvinylpyrrolidone-coated catheters decrease choroid plexus adhesion and improve flow/pressure performance in an in vitro model of hydrocephalus

PURPOSE

Proximal catheter obstruction is the leading cause of ventricular shunt failure in pediatric patients. Our aim is to evaluate various types of shunt catheters to assess in vitro cellular adhesion and obstruction.

METHODS

Four catheter types were tested: (1) antibiotic and impregnated, (2) barium-stripe polyvinylpyrrolidone coated (PVP), (3) barium-stripe, and (4) barium-impregnated. Catheters were seeded with choroid plexus epithelial cells to test cellular adhesion and inoculated with the same cells to test flow/pressure performance under choroid plexus growth conditions. Ventricular catheters were placed into a three-dimensional printed phantom ventricular replicating system through which artificial cerebrospinal fluid (CSF) was pumped. Differential pressure sensors were used to measure catheter performance.

RESULTS

PVP catheters had the lowest median cell attachment (10 cells) compared to antibiotic-impregnated (230 cells), barium stripe (513 cells), and barium-impregnated (146 cells) catheters after culture (p < 0.01). In addition, PVP catheters (- 0.247 cm H2O) and antibiotic-impregnated (- 1.15 cm H2O) catheters had significantly lower pressure in the phantom ventricular system compared to the barium stripe (0.167 cm H2O) and barium-impregnated (0.618 cm H2O; p < 0.01) catheters.

CONCLUSIONS

PVP catheters showed less cellular adhesion and, together with antibiotic-impregnated catheters, required less differential pressure to maintain a consistent flow. Our findings suggest clinical relevance for using PVP ventricular catheters in patients with recurrent catheter obstruction by choroid plexus.

Paediatric ventriculoperitoneal shunt failures: 12-year experience from a Singapore children's hospital

PURPOSE

Cerebrospinal fluid (CSF) shunt failures in children are devastating. The primary aims of this study are to, firstly, review our institutional series of ventriculoperitoneal shunt (VPS) insertions and identify factors associated with shunt failure.

METHODS

This is a single-institution, retrospective study conducted over a 12-year period. All patients under 18 years old with VPS inserted were included. Variables of interest such as patient characteristics, hydrocephalus aetiology, shunt implant details, and outcomes were subjected to statistical analyses.

RESULTS

A total of 214 VPS patients were selected for this study. The mean age at VPS insertion was 6 months with a mean follow-up duration of 44 months. The most common type of hydrocephalus was obstructive (n = 142, 66.4%), and the most frequent aetiology was tumour-related (n = 66, 30.8%). The 30-day shunt failure rate was 9.3%: 9 infections (4.2%), 7 occlusions (3.3%), and 4 others (1.9%). After multivariable analysis, only recent central nervous system (CNS) infection prior to VPS insertion remained significant (OR 15.4 (1.3-175), p = 0.028).

CONCLUSION

This is the first, large-scale local study focused on the shunt failure in Singaporean children. Significant findings in our study demonstrate that recently treated CNS infection is a factor associated with 30-day shunt failure while the values of CSF constituents were not contributory.

Dual function of the choroid plexus: Cerebrospinal fluid production and control of brain ion homeostasis

The choroid plexus is a small monolayered epithelium located in the brain ventricles and serves to secrete the cerebrospinal fluid (CSF) that envelops the brain and fills the central ventricles. The CSF secretion is sustained with a concerted effort of a range of membrane transporters located in a polarized fashion in this tissue. Prominent amongst these are the Na+/K+-ATPase, the Na+,K+,2Cl- cotransporter (NKCC1), and several HCO3- transporters, which together support the net transepithelial transport of the major electrolytes, Na+ and Cl-, and thus drive the CSF secretion. The choroid plexus, in addition, serves an important role in keeping the CSF K+ concentration at a level compatible with normal brain function. The choroid plexus Na+/K+-ATPase represents a key factor in the barrier-mediated control of the CSF K+ homeostasis, as it increases its K+ uptake activity when faced with elevated extracellular K+ ([K+]o). In certain developmental or pathological conditions, the NKCC1 may revert its net transport direction to contribute to CSF K+ homeostasis. The choroid plexus ion transport machinery thus serves dual, yet interconnected, functions with its contribution to electrolyte and fluid secretion in combination with its control of brain K+ levels.

Ventriculoperitoneal Shunt Surgery in Brunei Darussalam: A Population-Based Perspective

Objective  Ventriculoperitoneal shunt surgery is commonly performed to treat hydrocephalus. We aimed to characterize the demographics, complications, and outcomes of patients who underwent ventriculoperitoneal shunt surgery in Brunei Darussalam. Materials and Methods  We conducted a retrospective study on patients who underwent ventriculoperitoneal shunt surgery at the Neurosurgery Department of the Raja Isteri Pengiran Anak Saleha Hospital and Brunei Neuroscience Stroke and Rehabilitation Centre between January 2015 and June 2020. Statistical Analysis  All statistical analyses were performed using the Statistical Package for the Social Sciences version 20 (IBM Corporation, Armonk, New York, United States). The χ 2 test, Student's t -test, and Mann-Whitney U test were performed for nominal, normally, and non-normally distributed variables, respectively. Multivariate logistic regression was used to assess the predictors of complications and shunt failure. Results  Fifty-three patients with a median age of 33 (interquartile range, 4-49) years were included. A total of 53 shunt operations were performed: 18 in the pediatric population and 35 in adults. The overall complication rate was 22.6%. Infection was the most common (9.4%) complication, with coagulase-negative staphylococci being the common organism causing the infection. The shunt failure rate (defined as removal or revision) was 20.8%. Univariate and multivariate analyses did not identify factors associated with complications or shunt failure. Conclusion  Ventriculoperitoneal shunt surgery, a common and technically non-demanding neurosurgical procedure, is associated with significant complications. We highlighted that shunt infection remains a concern and advocate practices to negate this risk.

Endoscopic Third Ventriculostomy Using Penumbra Artemis™ Neuro Evacuation Device: Technical Case Report and Operative Video

Endoscopic third ventriculostomy (ETV) is an effective cerebrospinal fluid diversion procedure but can be complicated by the presence of a high-riding basilar artery (BA). A 70-year-old female presented with obstructive hydrocephalus caused by melanoma metastatic to the brainstem in the setting of a high-riding BA. ETV was successfully performed using the Penumbra Artemis™ Neuro evacuation device (Artemis; Penumbra Inc, Alameda, CA, USA) to minimize the risk of injury to the BA. This is to our knowledge the first known Artemis-assisted ETV reported in the English literature, which may reduce the risk of BA injury in selected patients. Further characterization of the benefits and limitations of this procedure is needed.

Establishing ranked priorities for future hydrocephalus research

OBJECTIVE

The aim of this initiative was to develop a ranked list of hydrocephalus research priorities as determined by the hydrocephalus patient community in conjunction with the healthcare and scientific community.

METHODS

Using the validated methodology published by the James Lind Alliance (JLA), the Hydrocephalus Association (HA) administered two surveys and hosted a final prioritization workshop. Survey One solicited open-ended responses from the community. From these responses, a long list of priority statements was developed. This list was then consolidated into a short list of research priority statements, which, after a nonsystematic literature review, were verified as being research uncertainties. Survey Two asked the community members to select their top 10 priorities from the short list. The final prioritization leading to a final ranked top 20 list of hydrocephalus research priorities took place at a virtual workshop led by a team of trained facilitators, by means of an iterative process of consensus building.

RESULTS

From Survey One, 3703 responses from 890 respondents were collected, leading to a long list of 146 priority statements. The consolidated short list contained 49 research priority statements, all of which were verified as uncertainties in hydrocephalus research. From an analysis of Survey Two responses, the top 21 research priority statements were determined. A consensus on these statements was reached at the virtual workshop, leading to a final ranked top 20 list of hydrocephalus research priorities, within which needs were apparent in several areas: development of noninvasive and/or one-time therapies, reduction of the burden of current treatments, improvement of the screening and diagnosis of hydrocephalus, improved quality of life, and improved access to care.

CONCLUSIONS

By gathering extensive input from the hydrocephalus community and using an iterative process of consensus building, a ranked list of the top 20 hydrocephalus research priorities was developed. The HA will use this ranked list to guide future research programs and encourages the healthcare and scientific community to do the same.

Impaired neurogenesis with reactive astrocytosis in the hippocampus in a porcine model of acquired hydrocephalus

BACKGROUND

Hydrocephalus is a neurological disease with an incidence of 0.3-0.7 per 1000 live births in the United States. Ventriculomegaly, periventricular white matter alterations, inflammation, and gliosis are among the neuropathologies associated with this disease. We hypothesized that hippocampus structure and subgranular zone neurogenesis are altered in untreated hydrocephalus and correlate with recognition memory deficits.

METHODS

Hydrocephalus was induced by intracisternal kaolin injections in domestic juvenile pigs (43.6 ± 9.8 days). Age-matched sham controls received similar saline injections. MRI was performed to measure ventricular volume, and/or hippocampal and perirhinal sizes at 14 ± 4 days and 36 ± 8 days post-induction. Recognition memory was assessed one week before and after kaolin induction. Histology and immunohistochemistry in the hippocampus were performed at sacrifice.

RESULTS

The hippocampal width and the perirhinal cortex thickness were decreased (p < 0.05) in hydrocephalic pigs 14 ± 4 days post-induction. At sacrifice (36 ± 8 days post-induction), significant expansion of the cerebral ventricles was detected (p = 0.005) in hydrocephalic pigs compared with sham controls. The area of the dorsal hippocampus exhibited a reduction (p = 0.035) of 23.4% in the hydrocephalic pigs at sacrifice. Likewise, in hydrocephalic pigs, the percentages of neuronal precursor cells (doublecortin+ cells) and neurons decreased (p < 0.01) by 32.35%, and 19.74%, respectively, in the subgranular zone of the dorsal hippocampus. The percentage of reactive astrocytes (vimentin+) was increased (p = 0.041) by 48.7%. In contrast, microglial cells were found to decrease (p = 0.014) by 55.74% in the dorsal hippocampus in hydrocephalic pigs. There was no difference in the recognition index, a summative measure of learning and memory, one week before and after the induction of hydrocephalus.

CONCLUSION

In untreated juvenile pigs, acquired hydrocephalus caused morphological alterations, reduced neurogenesis, and increased reactive astrocytosis in the hippocampus and perirhinal cortex.

A year in review: brain barriers and brain fluids research in 2022

This aim of this editorial is to highlight progress made in brain barrier and brain fluid research in 2022. It covers studies on the blood-brain, blood-retina and blood-CSF barriers (choroid plexus and meninges), signaling within the neurovascular unit and elements of the brain fluid systems. It further discusses how brain barriers and brain fluid systems are impacted in CNS diseases, their role in disease progression and progress being made in treating such diseases.

Ventriculopleural shunt outcomes for pediatric hydrocephalus: a single-institution experience

PURPOSE

The aim of this study is to analyze rates of ventriculopleural (VPL) shunt failure and complications among patients with pediatric hydrocephalus, and to analyze which factors may predict early (< 1 year) or late (> 1 year) VPL shunt failure in this sample.

METHODS

A retrospective chart review was conducted of all consecutive VPL shunt placements from 2000 to 2019 at our institution. Data was collected on patient characteristics, shunt history, and shunt type. Primary endpoints include rates of VPL shunt survival and rates of symptomatic pleural effusion. The Kaplan-Meier method was used to calculate shunt survival, and Fisher's exact test and t-test were used to compare differences between categorical variables and means, respectively (p < 0.05).

RESULTS

Thirty-one patients with pediatric hydrocephalus underwent VPL shunt placement (mean age 14.2 years). Of the 27 patients with long-term follow-up (mean 46 months), VPL shunt revision was required in 19, seven of which were due to pleural effusion. Overall shunt survival rates at 1, 3, 5, and 7 years were 76%, 62%, 55%, and 46%, respectively. Mean duration of shunt survival was 26.74 months. Overall pleural effusion rate was 26%. No patient-specific factors, including shunt valve type, were significantly associated with shunt survival, risk of early revision, or risk of pleural effusion.

CONCLUSIONS

Our results are comparable to those reported in the literature and represent one of the largest case series on the topic. VPL shunts are a viable second-line option when ventriculoperitoneal (VP) shunt placement is not possible or desirable, though there are high rates of shunt revision and pleural effusion.

Consideration of Kinase Inhibitors for the Treatment of Hydrocephalus

Hydrocephalus is a devastating condition characterized by excess cerebrospinal fluid (CSF) in the brain. Currently, the only effective treatment is surgical intervention, usually involving shunt placement, a procedure prone to malfunction, blockage, and infection that requires additional, often repetitive, surgeries. There are no long-term pharmaceutical treatments for hydrocephalus. To initiate an intelligent drug design, it is necessary to understand the biochemical changes underlying the pathology of this chronic condition. One potential commonality in the various forms of hydrocephalus is an imbalance in fluid–electrolyte homeostasis. The choroid plexus, a complex tissue found in the brain ventricles, is one of the most secretory tissues in the body, producing approximately 500 mL of CSF per day in an adult human. In this manuscript, two key transport proteins of the choroid plexus epithelial cells, transient receptor potential vanilloid 4 and sodium, potassium, 2 chloride co-transporter 1, will be considered. Both appear to play key roles in CSF production, and their inhibition or genetic manipulation has been shown to affect CSF volume. As with most transporters, these proteins are regulated by kinases. Therefore, specific kinase inhibitors are also potential targets for the development of pharmaceuticals to treat hydrocephalus.

A mathematical framework for the dynamic interaction of pulsatile blood, brain, and cerebrospinal fluid

BACKGROUND

Shedding light on less-known aspects of intracranial fluid dynamics may be helpful to understand the hydrocephalus mechanism. The present study suggests a mathematical framework based on in vivo inputs to compare the dynamic interaction of pulsatile blood, brain, and cerebrospinal fluid (CSF) between the healthy subject and the hydrocephalus patient.

METHOD

The input data for the mathematical formulations was pulsatile blood velocity, which was measured using cine PC-MRI. Tube law was used to transfer the created deformation by blood pulsation in the vessel circumference to the brain domain. The pulsatile deformation of brain tissue with respect to time was calculated and considered to be inlet velocity in the CSF domain. The governing equations in all three domains were continuity, Navier-Stokes, and concentration. We used Darcy law with defined permeability and diffusivity values to define the material properties in the brain.

RESULTS

We validated the preciseness of the CSF velocity and pressure through the mathematical formulations with cine PC-MRI velocity, experimental ICP, and FSI simulated velocity and pressure. We used the analysis of dimensionless numbers including Reynolds, Womersley, Hartmann, and Peclet to evaluate the characteristics of the intracranial fluid flow. In the mid-systole phase of a cardiac cycle, CSF velocity had the maximum value and CSF pressure had the minimum value. The maximum and amplitude of CSF pressure, as well as CSF stroke volume, were calculated and compared between the healthy subject and the hydrocephalus patient.

CONCLUSION

The present in vivo-based mathematical framework has the potential to gain insight into the less-known points in the physiological function of intracranial fluid dynamics and the hydrocephalus mechanism.

Hydrocephalus: A neuropsychological and theoretical primer

Hydrocephalus is a common neurological condition, the hallmark feature of which is an excess in production, or accumulation, of cerebrospinal fluid in the ventricles. Although it is associated with diffuse damage to paraventricular brain areas, patients are broadly typified by a particular pattern of cognitive impairments that include deficits in working memory, attention, and spatial abilities. There have, however, been relatively few neuropsychological accounts of the condition. Moreover, theories of the relationship between aetiology and impairment appear to have emerged in isolation of each other, and proffer fundamentally different accounts. In this primer, we aim to provide a comprehensive and contemporary overview of hydrocephalus for the neuropsychologist, covering cognitive sequelae and theoretical interpretations of their origins. We review clinical and neuropsychological assays of cognitive profiles, along with the few studies that have addressed more integrative behaviours. In particular, we explore the distinction between congenital or early-onset hydrocephalus with a normal-pressure variant that can be acquired later in life. The relationship between these two populations is a singularly interesting one in neuropsychology since it can allow for the examination of typical and atypical developmental trajectories, and their interaction with chronic and acute impairment, within the same broad neurological condition. We reflect on the ramifications of this for our subject and suggest avenues for future research.

Placebo-Controlled Effectiveness of Idiopathic Normal Pressure Hydrocephalus Shunting: A Randomized Pilot Trial

BACKGROUND

Multiple prospective nonrandomized studies have shown 60% to 70% of patients with idiopathic normal pressure hydrocephalus (iNPH) improve with shunt surgery, but multicenter placebo-controlled trial data are necessary to determine its effectiveness.

OBJECTIVE

To evaluate the effectiveness of cerebrospinal fluid shunting in iNPH through comparison of open vs placebo shunting groups at 4 months using a pilot study.

METHODS

Patients were randomized to a Codman Certas Plus valve (Integra LifeSciences) set at 4 (open shunt group) or 8 ("virtual off"; placebo group). Patients and assessors were blinded to treatment group. The primary outcome measure was 10-m gait velocity. Secondary outcome measures included functional scales for bladder control, activities of daily living, depression, and quality of life. Immediately after 4-month evaluation, all shunts were adjusted in a blinded fashion to an active setting and followed to 12 months after shunting.

RESULTS

A total of 18 patients were randomized. At the 4-month evaluation, gait velocity increased by 0.28 ± 0.28 m/s in the open shunt group vs 0.04 ± 0.17 m/s in the placebo group. The estimated treatment difference was 0.22 m/s ([ P = .071], 95% CI -0.02 to 0.46). Overactive Bladder Short Form symptom bother questionnaire significantly improved in open shunt vs placebo ( P = .007). The 4-month treatment delay did not reduce the subsequent response to active shunting, nor did it increase the adverse advents rate at 12 months.

CONCLUSION

This multicenter, randomized pilot study demonstrates the effectiveness, safety, and feasibility of a placebo-controlled trial in iNPH, and found a trend suggesting gait velocity improves more in the open shunt group than in the placebo group.

A standardized infection prevention bundle for reduction of CSF shunt infections in adult ventriculoperitoneal shunt surgery performed without antibiotic-impregnated catheters

OBJECTIVE

Ventriculoperitoneal (VP) shunt insertion and revision surgeries are some of the most common procedures that are performed by neurosurgeons. Shunt infections within the adult population are associated with significant morbidity and mortality and rates remain high. The objective of the current study was to use quality improvement (QI) methodology to create a standardized infection prevention bundle aimed at reducing the rate of shunt infections.

METHODS

A prospective, single-center, single-surgeon QI study was undertaken. Patients were included if they were 18 years of age or older and were undergoing a VP shunt insertion or revision. The primary outcome of the study was the development of a shunt-related surgical site infection, within 1 year of surgery, as defined according to the Canadian Nosocomial Infection Surveillance Program guidelines. There was no standardized protocol prior to July 2013. A bundle coined as the Calgary Adult Shunt Infection Prevention Protocol (CASIPP) was implemented on July 1, 2013, and updated on July 1, 2015, when 2% chlorhexidine gluconate in 70% isopropyl alcohol replaced povidone-iodine for preoperative skin antisepsis. Protocol compliance was regularly monitored using a standardized process. No antibiotic-impregnated catheters were used.

RESULTS

A total of 621 consecutive VP shunt insertions and revisions were included in the study. The rate of shunt infection was 5.8% during the period in which there was no standardized shunt protocol. After the implementation of the CASIPP the infection rate decreased to 4.0%, and after introduction of the chlorhexidine/alcohol skin antisepsis, the infection rate was 0% in 379 consecutive procedures (p < 0.0001). Multivariable logistic regression analysis demonstrated that the use of chlorhexidine/alcohol with CASIPP was associated with a significant reduction in the odds of developing a shunt infection (OR 0.032, 95% CI 0-0.19, p = 0.0005).

CONCLUSIONS

The implementation of a standardized shunt infection prevention bundle within the adult population, without the use of antibiotic-impregnated catheters, significantly reduced the rate of shunt infections which was sustained over many years. The use of 2% chlorhexidine gluconate in 70% isopropyl alcohol for preoperative antisepsis may have played a significant role. Multicenter studies should be completed to verify the effectiveness of the authors' protocol.

Outcomes of the 2019 hydrocephalus association workshop, "Driving common pathways: extending insights from posthemorrhagic hydrocephalus"

The Hydrocephalus Association (HA) workshop, Driving Common Pathways: Extending Insights from Posthemorrhagic Hydrocephalus, was held on November 4 and 5, 2019 at Washington University in St. Louis. The workshop brought together a diverse group of basic, translational, and clinical scientists conducting research on multiple hydrocephalus etiologies with select outside researchers. The main goals of the workshop were to explore areas of potential overlap between hydrocephalus etiologies and identify drug targets that could positively impact various forms of hydrocephalus. This report details the major themes of the workshop and the research presented on three cell types that are targets for new hydrocephalus interventions: choroid plexus epithelial cells, ventricular ependymal cells, and immune cells (macrophages and microglia).

Antibacterial and biocompatibility studies of triple antibiotics-impregnated external ventricular drainage: In vitro and in vivo evaluation

Hydrocephalus is a neurological disease caused by an unusually high level of cerebrospinal fluid (CSF), which can be relieved by external ventricular drainage (EVD) insertion. However, the infection can lead to complications during the use of EVD. In this study, EVD was impregnated with three synergistic antibiotics, including rifampicin, clindamycin, and trimethoprim, to improve the antibacterial property. The impregnated drainage was studied for its characteristics in vitro and in vivo. Drug loading determination revealed that rifampicin had the highest concentration in the tube, followed by clindamycin and trimethoprim, respectively. In vitro cytotoxicity and hemolytic studies showed no toxic effects from antibiotics-impregnated EVD on fibroblast and red blood cells. For antibacterial testing, the impregnated EVD exhibited antibacterial activity against Staphylococcus aureus MRSA and Staphylococcus epidermidis up to 14 and 90 days, respectively. Moreover, biocompatibility and drug release into the bloodstream and surrounding tissues were investigated by implantation in rabbits for 30 days. Histology and morphology results showed that fibroblast cells began to adhere to the drainage surface and inflammatory cell numbers were noticeably small after the long-term implantation. In addition, there was no drug leakage to the bloodstream and surrounding tissues. Hence, this impregnated EVD can potentially be used for antibacterial application.

Hydroflex: Use of Patient Reported Outcomes in a Clinical Setting Among Patients with Hydrocephalus

OBJECTIVE/BACKGROUND

A patient-reported outcome (PRO) measure is defined as "any report of the status of a patient's health condition that comes directly from the patient without interpretation of the patient's response by a clinician or anyone else". PRO data are increasingly being used in health care to facilitate monitoring of symptoms, facilitate communication between patients and clinicians, facilitate early identification of problems, and reduce unnecessary outpatient appointments for stable patients.

METHODS

We have designed a PRO system specifically for hydrocephalus, a program named Hydroflex. The aim of Hydroflex is to use PRO measures to decide the need for clinical attention and let the patients report their need regarding a physical consultation. Patients receive questionnaires at home instead of having prescheduled appointments at the outpatient clinic. Based on an automated algorithm, the patients' PRO measures are ranked to help clinical decision-making.

RESULTS

In this paper, we describe the implementation and early experience of Hydroflex at our institution.

CONCLUSIONS

It is our belief that Hydroflex provides more continuity in the treatment of patients with hydrocephalus. Also, it provides for a more standardized follow-up scheme, and we postulate this will lead to improved patient satisfaction and involvement and fewer outpatient appointments. Also, Hydroflex is useful for quality control and prospective research.

Failure of Internal Cerebrospinal Fluid Shunt: A Systematic Review and Meta-Analysis of the Overall Prevalence in Adults

OBJECTIVE

Reported rates of failures of internal cerebrospinal fluid shunt (ICSFS) vary greatly from less than 5% to more than 50% and no meta-analysis to assess the overall prevalence has been performed. We estimated the failure rate after ICSFS insertion and searched for associated factors.

METHODS

Six databases were searched from January 1990 to February 2022. Only original articles reporting the rate of adult shunt failure were included. Random-effects meta-analysis with a generalized linear mixed model method and logit transformation was used to compute the overall failure prevalence. Subgroup analysis and meta-regression were implemented to search for associated factors.

RESULTS

Of 1763 identified articles, 46 were selected, comprising 70,859 ICSFS implantations and 13,603 shunt failures, suggesting an accumulated incidence of 19.2%. However, the calculated pooled prevalence value and its 95% confidence interval (CI) were 22.7% (95% CI, 19.8-5.8). The CI of the different estimates did not overlap, indicating a strong heterogeneity confirmed by a high I² of 97.5% (95% CI, 97.1-97.8; P < 0.001; τ² = 0.3). Ninety-five percent prediction interval of shunt failure prevalence ranged from 8.75% to 47.36%. A meta-regression of prevalence of publication found a barely significant decreasing failure rate of about 2% per year (-2.11; 95% CI, -4.02 to -0.2; P = 0.031).

CONCLUSIONS

Despite being a simple neurosurgical procedure, ICSFS insertion has one of the highest risk of complications, with failure prevalence involving more than 1 patient of 5. Nonetheless, all efforts to lower this high level of shunt failure seem to be effective.

Polyvinylpyrrolidone-Coated Catheters Decrease Astrocyte Adhesion and Improve Flow/Pressure Performance in an Invitro Model of Hydrocephalus

The leading cause of ventricular shunt failure in pediatric patients is proximal catheter occlusion. Here, we evaluate various types of shunt catheters to assess in vitro cellular adhesion and obstruction. The following four types of catheters were tested: (1) antibiotic- and barium-impregnated, (2) polyvinylpyrrolidone, (3) barium stripe, and (4) barium impregnated. Catheters were either seeded superficially with astrocyte cells to test cellular adhesion or inoculated with cultured astrocytes into the catheters to test catheter performance under obstruction conditions. Ventricular catheters were placed into a three-dimensional printed phantom ventricular replicating system through which artificial CSF was pumped. Differential pressure sensors were used to measure catheter performance. Polyvinylpyrrolidone catheters had the lowest median cell attachment compared to antibiotic-impregnated (18 cells), barium stripe (17 cells), and barium-impregnated (21.5 cells) catheters after culture (p < 0.01). In addition, polyvinylpyrrolidone catheters had significantly higher flow in the phantom ventricular system (0.12 mL/min) compared to the antibiotic coated (0.10 mL/min), barium stripe (0.02 mL/min) and barium-impregnated (0.08 mL/min; p < 0.01) catheters. Polyvinylpyrrolidone catheters showed less cellular adhesion and were least likely to be occluded by astrocyte cells. Our findings can help suggest patient-appropriate proximal ventricular catheters for clinical use.

Type IV Pili Are a Critical Virulence Factor in Clinical Isolates of Paenibacillus thiaminolyticus

Hydrocephalus, the leading indication for childhood neurosurgery worldwide, is particularly prevalent in low- and middle-income countries. Hydrocephalus preceded by an infection, or postinfectious hydrocephalus, accounts for up to 60% of hydrocephalus in these areas. Since many children with hydrocephalus suffer poor long-term outcomes despite surgical intervention, prevention of hydrocephalus remains paramount. Our previous studies implicated a novel bacterial pathogen, Paenibacillus thiaminolyticus, as a causal agent of neonatal sepsis and postinfectious hydrocephalus in Uganda. Here, we report the isolation of three P. thiaminolyticus strains, Mbale, Mbale2, and Mbale3, from patients with postinfectious hydrocephalus. We constructed complete genome assemblies of the clinical isolates as well as the nonpathogenic P. thiaminolyticus reference strain and performed comparative genomic and proteomic analyses to identify potential virulence factors. All three isolates carry a unique beta-lactamase gene, and two of the three isolates exhibit resistance in culture to the beta-lactam antibiotics penicillin and ampicillin. In addition, a cluster of genes carried on a mobile genetic element that encodes a putative type IV pilus operon is present in all three clinical isolates but absent in the reference strain. CRISPR-mediated deletion of the gene cluster substantially reduced the virulence of the Mbale strain in mice. Comparative proteogenomic analysis identified various additional potential virulence factors likely acquired on mobile genetic elements in the virulent strains. These results provide insight into the emergence of virulence in P. thiaminolyticus and suggest avenues for the diagnosis and treatment of this novel bacterial pathogen. IMPORTANCE Postinfectious hydrocephalus, a devastating sequela of neonatal infection, is associated with increased childhood mortality and morbidity. A novel bacterial pathogen, Paenibacillus thiaminolyticus, is highly associated with postinfectious hydrocephalus in an African cohort. Whole-genome sequencing, RNA sequencing, and proteomics of clinical isolates and a reference strain in combination with CRISPR editing identified type IV pili as a critical virulence factor for P. thiaminolyticus infection. Acquisition of a type IV pilus-encoding mobile genetic element critically contributed to converting a nonpathogenic strain of P. thiaminolyticus into a pathogen capable of causing devastating diseases. Given the widespread presence of type IV pilus in pathogens, the presence of the type IV pilus operon could serve as a diagnostic and therapeutic target in P. thiaminolyticus and related bacteria.

Deep Learning Achieves Neuroradiologist-Level Performance in Detecting Hydrocephalus Requiring Treatment

In large clinical centers a small subset of patients present with hydrocephalus that requires surgical treatment. We aimed to develop a screening tool to detect such cases from the head MRI with performance comparable to neuroradiologists. We leveraged 496 clinical MRI exams collected retrospectively at a single clinical site from patients referred for any reason. This diagnostic dataset was enriched to have 259 hydrocephalus cases. A 3D convolutional neural network was trained on 16 manually segmented exams (ten hydrocephalus) and subsequently used to automatically segment the remaining 480 exams and extract volumetric anatomical features. A linear classifier of these features was trained on 240 exams to detect cases of hydrocephalus that required treatment with surgical intervention. Performance was compared to four neuroradiologists on the remaining 240 exams. Performance was also evaluated on a separate screening dataset of 451 exams collected from a routine clinical population to predict the consensus reading from four neuroradiologists using images alone. The pipeline was also tested on an external dataset of 31 exams from a 2nd clinical site. The most discriminant features were the Magnetic Resonance Hydrocephalic Index (MRHI), ventricle volume, and the ratio between ventricle and brain volume. At matching sensitivity, the specificity of the machine and the neuroradiologists did not show significant differences for detection of hydrocephalus on either dataset (proportions test, p > 0.05). ROC performance compared favorably with the state-of-the-art (AUC 0.90-0.96), and replicated in the external validation. Hydrocephalus cases requiring treatment can be detected automatically from MRI in a heterogeneous patient population based on quantitative characterization of brain anatomy with performance comparable to that of neuroradiologists.

Aetiology and diagnostics of paediatric hydrocephalus across Africa: a systematic review and meta-analysis

BACKGROUND

We aimed to identify the aetiological distribution and the diagnostic methods for paediatric hydrocephalus across Africa, for which there is currently scarce evidence.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE (Ovid), the Cochrane Database of Systematic Reviews (Wiley), Embase (Ovid), Global Health (Ovid), Maternity & Infant Care (Ovid), Scopus, African Index Medicus (Global Index Medicus, WHO) and Africa-Wide Information (EBSCO) from inception to Nov 29, 2021. We included studies from any African country reporting on the distribution of hydrocephalus aetiology in children aged 18 years and younger, with no language restrictions. Hydrocephalus was defined as radiological evidence of ventriculomegaly or associated clinical symptoms and signs of the disorder, or surgical treatment for hydrocephalus. Exclusion criteria were studies only reporting on one specific subgroup or one specific cause of hydrocephalus. We also excluded conference and meetings abstracts, grey literature, editorials, commentaries, historical reviews, systematic reviews, case reports and clinical guidelines, as well as studies on non-humans, fetuses, or post-mortem reports. The proportions of postinfectious hydrocephalus, non-postinfectious hydrocephalus, and hydrocephalus related to spinal dysraphism were calculated using a random-effects model. Additionally, we included a category for unclear cases. Diagnostic methods were described qualitatively. To assess methodological study quality, we applied critical appraisal checklists provided by the Joanna Briggs Institute. The study was registered in Prospero (CRD42020219038).

FINDINGS

Our search yielded 3783 results, of which 1880 (49·7%) were duplicates and were removed. The remaining 1903 abstracts were screened and 122 (6·4%) full articles were sought for retrieval; of these, we included 38 studies from 18 African countries that studied a total of 6565 children. The pooled proportion of postinfectious hydrocephalus was 28% (95% CI 22-36), non-postinfectious hydrocephalus was 21% (95% CI 13-30), and of spinal dysraphism was 16% (95% CI 12-20), with substantial heterogeneity. The pooled proportion of hydrocephalus of unclear aetiology was 20% (95% CI 13-28).

INTERPRETATION

Our findings suggest that postinfectious hydrocephalus is the single most common cause of paediatric hydrocephalus in Africa. For targeted investments to be optimal, there is a need for consensus regarding the aetiological classification of hydrocephalus and improved access to diagnostic services.

FUNDING

Rikshospitalet, Oslo University Hospital, Oslo, Norway.

Ventricular Peritoneal Shunting Using Modified Keen’s Point Approach: Technical Report and Cases Series

Background: Ventricular peritoneal shunting (VPS) is a frequent procedure in neurosurgery, unfortunately still burdened with a significant rate of complications. The frontal Kocher’s point is the most frequently used landmark for ventricular puncture. Keen’s point (posterior parietal approach) seems to be a valid alternative. We report a newly described access to the lateral ventricle located in posterior temporal area and the results of a large series of adult patients. Methods: Retrospective analysis of a series of 188 cases of VPS performed with this approach. Results: Mean surgical time was 51.5 +/− 13.1 min (range 25–90 min). Twenty-one patients (11.2%) were subjected to revision surgery: eight cases (4.3%) for displacement or malfunction of ventricular catheter, eight cases (4.3%) for abdominal issues, three cases (1.6%) for hardware failure, and two cases (1.1%) for infection. Optimal catheter placement was reached in 90.1%. Conclusions: The modified Keen’s point approach seems to be safe, technically feasible, and reproducible, showing some potential advantages such as short surgical time, precision in ventricular catheter placement, and short tunneling tract. The need for surgical revision is similar to that reported in the literature, while the rate of catheter malpositioning and infections seems to be low; hemorrhages around catheter and seizures were not reported.

Long-term recovery behavior of brain tissue in hydrocephalus patients after shunting

The unpredictable complexities in hydrocephalus shunt outcomes may be related to the recovery behavior of brain tissue after shunting. The simulated cerebrospinal fluid (CSF) velocity and intracranial pressure (ICP) over 15 months after shunting were validated by experimental data. The mean strain and creep of the brain had notable changes after shunting and their trends were monotonic. The highest stiffness of the hydrocephalic brain was in the first consolidation phase (between pre-shunting to 1 month after shunting). The viscous component overcame and damped the input load in the third consolidation phase (after the fifteenth month) and changes in brain volume were stopped. The long-intracranial elastance (long-IE) changed oscillatory after shunting and there was not a linear relationship between long-IE and ICP. We showed the long-term effect of the viscous component on brain recovery behavior of hydrocephalic brain. The results shed light on the brain recovery mechanism after shunting and the mechanisms for shunt failure.

TRPV4 mRNA is elevated in the caudate nucleus with NPH but not in Alzheimer's disease

Symptoms of normal pressure hydrocephalus (NPH) and Alzheimer's disease (AD) are somewhat similar, and it is common to misdiagnose these two conditions. Although there are fluid markers detectable in humans with NPH and AD, determining which biomarker is optimal in representing genetic characteristics consistent throughout species is poorly understood. Here, we hypothesize that NPH can be differentiated from AD with mRNA biomarkers of unvaried proximity to telomeres. We examined human caudate nucleus tissue samples for the expression of transient receptor potential cation channel subfamily V member 4 (TRPV4) and amyloid precursor protein (APP). Using the genome data viewer, we analyzed the mutability of TRPV4 and other genes in mice, rats, and humans through matching nucleotides of six genes of interest and one house keeping gene with two factors associated with high mutation rate: 1) proximity to telomeres or 2) high adenine and thymine (A + T) content. We found that TRPV4 and microtubule associated protein tau (MAPT) mRNA were elevated in NPH. In AD, mRNA expression of TRPV4 was unaltered unlike APP and other genes. In mice, rats, and humans, the nucleotide size of TRPV4 did not vary, while in other genes, the sizes were inconsistent. Proximity to telomeres in TRPV4 was <50 Mb across species. Our analyses reveal that TRPV4 gene size and mutability are conserved across three species, suggesting that TRPV4 can be a potential link in the pathophysiology of chronic hydrocephalus in aged humans (>65 years) and laboratory rodents at comparable ages.

Evaluation of developmental profiles of children with hydrocephalus

OBJECTIVE

The objective of this study was to compare the developmental characteristics of children with hydrocephalus with those of healthy children.

MATERIAL AND METHODS

A total of 109 children aged between 2 and 46 months were included in the study, 54 patients diagnosed with hydrocephalus and 55 healthy children were evaluated with demographic data forms and Denver Developmental Screening Test II.

RESULTS

The mean personal-social (p<0.001), fine motor-adaptive (p<0.001), language (p<0.001), and gross motor subscale scores were significantly lower in children with hydrocephalus than in the control group. Personal-social (p=0.002) and gross motor (p=0.029) subscale scores were significantly lower in children with obstructive hydrocephalus than communicating hydrocephalus. There was a significant negative correlation between language scores and ages of the children with hydrocephalus (r=-0.350, p=0.009). It was found that children with obstructive hydrocephalus carry a 6.7 folds higher risk of experiencing problems in terms of personal-social development compared to those with communicating hydrocephalus (p=0.011).

CONCLUSION

We found that patients with hydrocephalus were developmentally retarded compared to the healthy control subjects. Retardation was the most prominent in the obstructive group. Our results showed that neurodevelopmental follow-up should be carried-out regularly in pediatric patients with hydrocephalus, and early intervention should be started in necessary cases.

The Effects of Using Hearing Aids and Hearing Assistive Technologies on Programmable Ventriculoperitoneal Shunt

BACKGROUND

To investigate interaction between behind-the-ear (BTE) hearing aids, hearing assistive technologies, and programmable shunt valve to understand how use of BTE hearing aids in patients who underwent ventriculoperitoneal shunt (VPS) surgery affects the settings of a programmable shunt valve.

METHODS

In this study, we investigated the magnetic field (MF) generation of 3 BTE hearing aids made by different companies, 1 frequency modulated system using telecoil technology, and 1 wireless microphone technology and their interactions with 2 programmable shunt valves. All measurements were made in a silent booth using 2 different models. The influence of MF strength in the distance modeling was investigated based on the distance from source auditory prostheses. The measurements were recorded using a Gauss meter. In the anatomical modeling, the change in the settings and interaction of the valve in a bust mannequin were investigated.

RESULTS

No MF created by BTE hearing aids was detected in the distance modeling. The highest value measured was 32.67 μT (<90 dB noise) when BTE hearing aids and frequency modulated systems were used, and this value decreased as the distance increased. No MF generation was observed at measurements done for distances >10 mm. In the anatomical modeling, the settings of both programmable valves did not change under all acoustic conditions.

CONCLUSIONS

This is the first study to our knowledge examining the MF created by hearing aids and hearing assistive technologies and its impact on programmable valves and variations in their settings. Our findings showed that it is safe to use BTE hearing aids, frequency modulated systems, and wireless microphone technologies in patients with a programmable VPS.

Contactless Ultrasonic Cavitation for the Prevention of Shunt Obstruction in Hydrocephalus: A Proof-of-Concept Study

BACKGROUND

Obstructive failure of implanted shunts is the most common complication in the treatment of hydrocephalus. Biological material and debris accumulate in the inner walls of the valve and catheters block the normal flow of the drained cerebrospinal fluid causing severe symptoms with high morbidity and mortality. Unfortunately, at present, there is no effective preventive protocol or cleaning procedure available.

OBJECTIVE

To assess whether externally applied, focused ultrasound beams can be used to resuspend deposits accumulated in brain shunts safely.

METHODS

A computational model of an implanted brain shunt was implemented to test the initial design parameters of a system comprising several ultrasound transducers. Under laboratory conditions, configurations with 3 and 4 transducers were arranged in a triangle and square pattern with their radiation axis directed towards a target model of the device, 2 catheters and a brain shunt filled with water and deposited graphite powder. The ultrasound beams were then concentrated on the device across a head model.

RESULTS

The computational model revealed that by using only 3 transducers, the acoustic field intensity on the valve was approximately twice that on the brain surface suggesting that acoustic cavitation could be selectively achieved. Resuspension of graphite deposits inside the catheters and the valve were then physically demonstrated and video-recorded with no temperature increase.

CONCLUSION

The technology presented here has the potential to be used routinely as a noninvasive, preventive cleaning procedure to reduce the likelihood of obstruction-related events in patients with hydrocephalus treated with an implanted shunt.

Etiology- and region-specific characteristics of transependymal cerebrospinal fluid flow

OBJECTIVE

Transependymal flow (TEF) of CSF, often delineated as T2-weighted hyperintensity adjacent to the lateral ventricles on MRI, is a known imaging finding, usually in the setting of CSF flow disturbances. Specific radiological features of TEF and their relationships with clinical markers of hydrocephalus and underlying disease pathology are not known. Here, the authors describe the radiological features and clinical associations of TEF with implications for CSF circulation in the setting of intracranial pathology.

METHODS

After obtaining IRB review and approval, the authors reviewed the radiological records of all patients who underwent intracranial imaging with CT or MRI at St. Louis Children's Hospital, St. Louis, Missouri, between 2008 and 2019 to identify individuals with TEF. Then, under direct review of imaging, TEF pattern, degree, and location and underlying pathology and other radiological and clinical features pertaining to CSF circulation and CSF disturbances were noted.

RESULTS

TEF of CSF was identified in 219 patients and was most prevalent in the setting of neoplasms (72%). In 69% of the overall cohort, TEF was seen adjacent to the anterior aspect of the frontal horns and the posterior aspect of the occipital horns of the lateral ventricles, and nearly half of these patients also had TEF dorsal to the third ventricle near the splenium of the corpus callosum. This pattern was independently associated with posterior fossa medulloblastoma when compared with pilocytic astrocytoma (OR 4.75, 95% CI 1.43-18.53, p = 0.0157). Patients with congenital or neonatal-onset hydrocephalus accounted for 13% of patients and were more likely to have TEF circumferentially around the ventricles without the fronto-occipital distribution. Patients who ultimately required permanent CSF diversion surgery were more likely to have the circumferential TEF pattern, a smaller degree of TEF, and a lack of papilledema at the time of CSF diversion surgery.

CONCLUSIONS

CSF transmigration across the ependyma is usually restricted to specific periventricular regions and is etiology specific. Certain radiological TEF characteristics are associated with tumor pathology and may reflect impaired or preserved ependymal fluid handling and global CSF circulation. These findings have implications for TEF as a disease-specific marker and in understanding CSF handling within the brain.

Case report: Ventriculoperitoneal shunt disconnection resulting in migration of the distal catheter entirely into the abdominal cavity due to seizure

Ventriculoperitoneal (VP) shunt disconnection, a VP shunt complication, can be caused by several factors. We report the case of a young man who suffered VP shunt disconnection, and whose entire distal catheter migrated into the abdominal cavity due to a seizure. To our knowledge, risk factors for seizures related to shunt disconnection have not been previously evaluated. We report this rare case to highlight the fact that seizures are not negligible in increasing the probability of disconnection and migration of the entire distal catheter into the abdominal cavity, and the standardized treatment of traumatic seizures is extremely important.

Partial Obstruction of Ventricular Catheters Affects Performance in a New Catheter Obstruction Model of Hydrocephalus

OBJECTIVE

One of the major causes of cerebral ventricular shunt failure is proximal catheter occlusion. We describe a novel ventricular cerebrospinal fluid (CSF) flow replicating system that assesses pressure and flow responses to varying degrees of catheter occlusion.

METHODS

Ventricular catheter performance was assessed during conditions of partial and complete occlusion. The catheters were placed into a three-dimensionally-printed phantom ventricular replicating system. Artificial CSF was pumped through the ventricular system at a constant rate of 1 mL/min to mimic CSF flow, with the proximal end of the catheter in the phantom ventricle. Pressure transducer and flow rate sensors were used to measure intra-phantom pressure, outflow pressure, and CSF flow rates. The catheters were also inserted into silicone tubing and pressure was measured in the same manner for comparison with the phantom.

RESULTS

Pressure measured in the ventricle phantom did not change when the outflow of the ventricular catheter was partially occluded. However, the intraventricular phantom pressure significantly increased when the outflow catheter was 100% occluded. The flow through the catheter showed no significant difference in rate with any degree of partial occlusion of the catheter. At the distal end of the partially occluded catheters, there was less pressure compared with the nonoccluded catheters. This difference in pressure in partially occluded catheters correlated with the percentage of catheter hole occlusion.

CONCLUSIONS

Our model mimics the physiological dynamics of the CSF flow in partially and completely obstructed ventricular catheters. We found that partial occlusion of the catheter had no effect on the CSF flow rate, but did reduce outflow pressure from the catheter.

Experiences of family caregivers of patients with post-traumatic hydrocephalus from hospital to home: a qualitative study

Background

Post-traumatic hydrocephalus (PTH) is a complication of traumatic brain injury (TBI) that requires treatment and postoperative care. The shunt is one of the main treatments for PTH, which presents with dysfunction and infection. Considering brain injury, hydrocephalus shunt malfunction, and infection, family caregivers need to be responsible for caring for PTH patients, recognizing shunt malfunction and infection, and managing those patients accordingly from hospital to home. Understanding the experiences and needs of caregivers is beneficial for knowing their competency and quality of health care, ameliorating and ensuring future transition care. The study aimed to explore the feelings, experiences, and needs of family caregivers when caring for patients with TBI, PTH and shunts.

Methods

This was exploratory research of a purposive sample of 12 family caregivers of adult patients with TBI, PTH and shunts in five neurosurgery departments at a general hospital in Zhengzhou, Henan Province, China, using a semi-structured interview method. Data were collected from October 2021 to March 2022 before being analyzed by content analysis methods.

Results

Caregivers required professional and social knowledge and support in the areas of TBI, PTH and shunts, caregiving interventions, psychological care needs, and health insurance, just as caregivers do, but unlike other general caregivers, care for patients with TBI, PTH, and shunt is fraught with uncertainty and the need to manage shunt setting, and caregivers often experience 'complex emotional reaction' during the transitional period, where care needs and complex emotions may lead to a lack of caregiver confidence, which in turn may affect caregiving behaviors, and experiences that affect care may be mediated through caregiving confidence. The perceived availability of resources, particularly those that are still available to them when they return home, has a significant impact on participants' emotional response and sense of confidence.

Conclusions

The emotional response and the impact of stressor caregivers after TBI, PTH, and shunt was important, and sometimes confidence in care appeared to be an intermediate and useful factor that needed to be considered as health professionals prepared to develop care resources on how to manage and empower patients with TBI, PTH, and shunt. Meanwhile, there may be gaps and inequities in supportive care for patients diagnosed with TBI, PTH, and shunt in China.

Gastrostomy and internal cerebrospinal fluid shunt in adults. A systematic review and meta-analysis of the risk of infection

BACKGROUND

Hydrocephalus is a frequent neurological condition, commonly treated by ventriculoperitoneal shunting (VPS), a neurosurgical procedure with significant risk of infection. Some severely brain-injured hydrocephalic patients with swallowing dysfunction may require percutaneous endoscopic gastrostomy (PEG). There are few data on the safety of PEG in patients with VPS, with contradictory results reported.

OBJECTIVE

The aim of this systematic review and meta-analysis was to determine the rate of VPS infection in the setting of PEG.

METHODS

Six databases were searched for the period January 1990 to June 2022. Only original articles reporting the rate of shunt infection in the setting of PEG in adults were included. Random-effects meta-analysis was used to assess the rate of infection.

RESULTS

Fifteen of the 1,703 identified articles were selected, reporting 701 internal cerebrospinal fluid shunts, with 63 infections. The pooled rate of infection in patients with both PEG and VPS was 7.41% (95% CI [3.67-14.38]). There was a significantly higher risk of VPS infection in the PEG group vs. the control group with VPS without PEG: relative risk (RR)=2.33 (95% CI [1.11-4.89]). On the other hand, the risk of infection was the same whether the PEG was placed before or after the VPS surgery: RR=1.05 (95% CI [0.57-1.92]).

CONCLUSION

Gastrostomy tube placement is a significant risk factor for VPS infection. However, onset of infection was not related to the sequence of or interval between VPS and PEG.

TRIAL REGISTRATION

This meta-analysis is registered in https://www.crd.york.ac.uk/PROSPERO/, PROSPERO ID: CRDCRD42022326774.

A New Definition for Intracranial Compliance to Evaluate Adult Hydrocephalus After Shunting

The clinical application of intracranial compliance (ICC), ∆V/∆P, as one of the most critical indexes for hydrocephalus evaluation was demonstrated previously. We suggest a new definition for the concept of ICC (long-term ICC) where there is a longer amount of elapsed time (up to 18 months after shunting) between the measurement of two values (V1 and V2 or P1 and P2). The head images of 15 adult patients with communicating hydrocephalus were provided with nine sets of imaging in nine stages: prior to shunting, and 1, 2, 3, 6, 9, 12, 15, and 18 months after shunting. In addition to measuring CSF volume (CSFV) in each stage, intracranial pressure (ICP) was also calculated using fluid–structure interaction simulation for the noninvasive calculation of ICC. Despite small increases in the brain volume (16.9%), there were considerable decreases in the ICP (70.4%) and CSFV (80.0%) of hydrocephalus patients after 18 months of shunting. The changes in CSFV, brain volume, and ICP values reached a stable condition 12, 15, and 6 months after shunting, respectively. The results showed that the brain tissue needs approximately two months to adapt itself to the fast and significant ICP reduction due to shunting. This may be related to the effect of the “viscous” component of brain tissue. The ICC trend between pre-shunting and the first month of shunting was descending for all patients with a “mean value” of 14.75 ± 0.6 ml/cm H2O. ICC changes in the other stages were oscillatory (nonuniform). Our noninvasive long-term ICC calculations showed a nonmonotonic trend in the CSFV–ICP graph, the lack of a linear relationship between ICC and ICP, and an oscillatory increase in ICC values during shunt treatment. The oscillatory changes in long-term ICC may reflect the clinical variations in hydrocephalus patients after shunting.

Imaging of Headaches due to Intracranial Pressure Disorders

Changes in intracranial pressure are a potentially serious etiology of headache. Headache secondary to changes in intracranial pressure frequently present with characteristic clinical features. Imaging plays a key role in the diagnosis and management of this category of headache. In this article, we will review the physiology, clinical presentation, and key imaging findings of major etiologies of changes in intracranial pressure resulting in headache including obstructive and nonobstructive hydrocephalous, idiopathic intracranial hypertension (IIH), and cerebrospinal fluid (CSF) leak.