Ventricular System Of Brain Research Articles

A standardized method to measure brain shifts with decompressive hemicraniectomy

BackgroundA standardized, reliable, and practical method for measuring decompressive hemicraniectomy (DHC) defects and brain shifts in malignant middle cerebral artery (MCA) territory infarction is needed for reliable comparisons between computed tomography (CT) scans. Such a method could facilitate further studies on the effects of DHC. New methodWe describe and apply a method for measuring DHC defects and brain shifts on CT scans in 25 patients with malignant MCA territory infarction. Craniectomy area is adjusted for variations in head size, CT slice orientation is standardized, and the site of each measurement is defined. This method uses standard radiology platforms and volume-acquired helical CT scans. ResultsThe measurements include a DHC size index (adjusted for variations in head size), midline brain shift (subfalcine), outward brain herniation (transcalvarial), and the diameter of the contralateral atrium of the lateral ventricle. Inter-rater agreement for these measurements in a sample of 15 subjects is excellent (correlation coefficients 0.90–0.98). Comparison with existing methodsIn contrast to previously reported methods, this method is tested in acute stroke patients, compensates for variability in head size, and includes a midline brain shift (subfalcine) and brain ventricular system measurements. ConclusionsA practical method for measuring DHC size and brain shifts designed to be consistent between scans is proposed. This method should facilitate comparisons of measurements between serial scans, between patients, and perhaps between studies. This method could be useful in medical and surgical studies of brain herniations in malignant MCA territory infarction, and possibly other conditions.

Morphological and Volumetric Assessment of Cerebral Ventricular System with 3D Slicer Software

We present a technological process based on the 3D Slicer software for the three-dimensional study of the brain's ventricular system with teaching purposes. It values the morphology of this complex brain structure, as a whole and in any spatial position, being able to compare it with pathological studies, where its anatomy visibly changes. 3D Slicer was also used to obtain volumetric measurements in order to provide a more comprehensive and detail representation of the ventricular system. We assess the potential this software has for processing high resolution images, taken from Magnetic Resonance and generate the three-dimensional reconstruction of ventricular system.

Ependymal tables designated for differentiation of the ependyma based on the adjacent periventricular structures

AbstractThe ependyma, lining of the brain ventricular system, is a heterogeneous structure. The brain ventricles, including the lateral-, third-, fourth-, and mesencephalic ones and cerebral aqueduct, are covered by a single uninterrupted layer, composed of squamous to columnar ependymocytes, possessing cilia, microvilli or cytoplasmic protrusions. Small ependymal areas are considered to be functionally different and therefore, accurate and systematic classification of ependymal areas might be helpful to perform mutual comparisons of the same types of ependymal areas under different experimental conditions. Thus, the aim of the present study was to create an anatomical guide that will be able to offer an easy and repeatable technique for the selection of anatomically precisely identified small ependymal areas. For this purpose, the periventricular structures, as a stable part of brain, localized most closely to the brain ventricle walls, were chosen as reference points. Classification of the ependymal areas is presented in a form of tables, i.e. ependymal tables, which prevent of an interchange of different types of ependymal areas, avoiding of their misinterpretation. Each table brings all the information needed to localize the selected ependymal sector in 5 columns, indicating: (1) the number of the frontal sections; (2) the labelling of the ventricle walls; (3) Latin names of the periventricular structures; (4) abbreviations of the periventricular structures; and (5) the final designation of the selected ependymal areas. The final designation of a small ependymal area is composed of several letters (e.g., "LvE-ca", where Lv = lateral ventricle, E = ependyma, and ca = caudate nucleus). The proposed anatomical classification of the ependymal lining represents an original approach with more unambiguous classification of ependymal areas than is only a structural naming of ependyma. This anatomical guide will be helpful in performing of an accurate mutual comparison of the same types of ependymal areas under different experimental conditions as well as a possibility to compare mutually the data from different morphological/biochemical studies.

Functional antagonism of voltage-gated K+ channel α-subunits in the developing brain ventricular system.

The brain ventricular system is essential for neurogenesis and brain homeostasis. Its neuroepithelial lining effects these functions, but the underlying molecular pathways remain to be understood. We found that the potassium channels expressed in neuroepithelial cells determine the formation of the ventricular system. The phenotype of a novel zebrafish mutant characterized by denudation of neuroepithelial lining of the ventricular system and hydrocephalus is mechanistically linked to Kcng4b, a homologue of the 'silent' voltage-gated potassium channel α-subunit Kv6.4. We demonstrated that Kcng4b modulates proliferation of cells lining the ventricular system and maintains their integrity. The gain of Kcng4b function reduces the size of brain ventricles. Electrophysiological studies suggest that Kcng4b mediates its effects via an antagonistic interaction with Kcnb1, the homologue of the electrically active delayed rectifier potassium channel subunit Kv2.1. Mutation of kcnb1 reduces the size of the ventricular system and its gain of function causes hydrocephalus, which is opposite to the function of Kcng4b. This demonstrates the dynamic interplay between potassium channel subunits in the neuroepithelium as a novel and crucial regulator of ventricular development in the vertebrate brain.

Birth weight-related percentiles of brain ventricular system as a tool for assessment of posthemorrhagic hydrocephalus and ventricular enlargement.

Besides remarkable improvements of neonatal medical therapy, neurological morbidity remains a major concern in preterm infants. In particular, intracranial hemorrhage is a severe complication strongly correlated to poor neurological outcome. For early clinical assessment of intracranial hemorrhage and its impact on the ventricular system, cranial sonography is an important bedside diagnostic tool. Reference values of ventricular sizes are available in relation to gestational age (GA). So far, it has not been demonstrated that ventricular size values are also reliable in relation to birth weight (BW). In this study, we performed cranial ultrasonography in 250 preterm and term newborn infants. Measurements of the intracranial ventricular system by cranial ultrasound examination were performed within 72 h after birth. We determined ventricular index, anterior horn width, width of the third ventricle, width and length of the fourth ventricle for statistical analysis in relation to BW and GA. GA ranged from 23 weeks, 3 days to 42 weeks, 1 day (mean: 33 weeks), BW ranged from 345 to 5620 g (mean: 2146 g). Ventricular index and fourth ventricle width revealed a significant correlation to birth weight with r=0.75, each. A significant correlation to birth weight was also obtained for width and length of the third ventricle (r=0.55 and 0.47, respectively). Correlations obtained for ventricular measures in relation to GA were similar to those referring to BW. In preterm and term infants, ventricular sizes in relation to BW seem reliable for assessment and monitoring of ventricular pathologies, i.e. after intracranial hemorrhage.

Generation of anatomy replicas of the human encefalic ventricular sistem by the Injection Corrosion technique

The anatomical study of the human brain ventricular system has been developed through theoretical components and illustrative premises. The difficult access to the wells and the limited availability of brain parts in medical schools, make the a priori contact with its anatomic architecture and three-dimensional structure, deficient in courses of first and second year of human medicine. The anatomical cavities are replicated from molds made with polyester resin which is implemented as a technique for study of complex anatomical structures such as the ventricular system, since its anatomical description presents difficulties in the comprehension of neuroscience; therefore currently the use of neutral resins as polymer for anatomical replicas has been implemented. They exhibiting a number of special characteristics such as pliability, conservation of structure, durability, low cost, low toxicity and the holder so, when subjected to low pressures. In this study brain replicas were generated from molds, provided by corrosion and injection, supplemented with plaster casts supported on polyester resin. The cavities of the brain ventricular system were obtained in three dimensions, keeping the initial anatomical contours of the replica of the ventricular system as a final result. The pieces were of good quality, being a useful as an appropriate tool for understanding the neuroanatomy, avoiding brain damage during handling, optimizing learning environments and improving the availability of anatomical parts in medical schools.

The experience of intrathecal fibrinolysis in surgery of massive intraventricular hemorrhage

Introduction. Intraventricular hemorrhage (IVH) was detected in 30% patients with hypertensive intracerebral hemorrhages, that significantly worsens disease prognosis and course. Lethality is particularly high at massive IVH. Methods. 29 patients with massive IVH were operated (severity of the patient’s condition according to Graeb scale 7–10 scores), level of consciousness at the time of operation according to Glasgow Coma Scale (GCS) 8 scores and lower. All patients were operated on the 1 st –2 nd day of the disease, on the 1 st day after hospitalization. For intrathecal fibrinolysis Actylise in doze 3,5 mg was used, it was introduced into each intraventricular catheter, exposure 3 hours. The procedure was repeated 4 times during 24 hours (every 6 hours). Results. 17 (58,6%) patients were discharged from the clinic. 5 patients’ condition scored 4 on Glasgow Outcome Scale, 7 scored 3, five scored 2. Fibrinolytics are effective even in patients with complete tamponade of brain ventricular system, but patient’s initial GCS score has to be no lower than 6. Conclusions. Intrathecal fibrinolysis is a promising method for massive IVH treatment. It is ineffective in patients, been hospitalized in critical condition, with GCS score lower than 6, and Graeb score 9–10.

Traumatic brain injury-induced ependymal ciliary loss decreases cerebral spinal fluid flow.

Traumatic brain injury (TBI) afflicts up to 2 million people annually in the United States and is the primary cause of death and disability in young adults and children. Previous TBI studies have focused predominantly on the morphological, biochemical, and functional alterations of gray matter structures, such as the hippocampus. However, little attention has been given to the brain ventricular system, despite the fact that altered ventricular function is known to occur in brain pathologies. In the present study, we investigated anatomical and functional alterations to mouse ventricular cilia that result from mild TBI. We demonstrate that TBI causes a dramatic decrease in cilia. Further, using a particle tracking technique, we demonstrate that cerebrospinal fluid flow is diminished, thus potentially negatively affecting waste and nutrient exchange. Interestingly, injury-induced ventricular system pathology resolves completely by 30 days after injury as ependymal cell ciliogenesis restores cilia density to uninjured levels in the affected lateral ventricle.

Blood borne hormones in a cross-talk between peripheral and brain mechanisms regulating blood pressure, the role of circumventricular organs

Accumulating evidence suggests that blood borne hormones modulate brain mechanisms regulating blood pressure. This appears to be mediated by the circumventricular organs which are located in the walls of the brain ventricular system and lack the blood–brain barrier. Recent evidence shows that neurons of the circumventricular organs express receptors for the majority of cardiovascular hormones. Intracerebroventricular infusions of hormones and their antagonists is one approach to evaluate the influence of blood borne hormones on the neural mechanisms regulating arterial blood pressure. Interestingly, there is no clear correlation between peripheral and central effects of cardiovascular hormones. For example, angiotensin II increases blood pressure acting peripherally and centrally, whereas peripherally acting pressor catecholamines decrease blood pressure when infused intracerebroventricularly. The physiological role of such dual hemodynamic responses has not yet been clarified.In the paper we review studies on hemodynamic effects of catecholamines, neuropeptide Y, angiotensin II, aldosterone, natriuretic peptides, endothelins, histamine and bradykinin in the context of their role in a cross-talk between peripheral and brain mechanisms involved in the regulation of arterial blood pressure.

Over-expression of hNGF in adult human olfactory bulb neural stem cells promotes cell growth and oligodendrocytic differentiation.

The adult human olfactory bulb neural stem/progenitor cells (OBNC/PC) are promising candidate for cell-based therapy for traumatic and neurodegenerative insults. Exogenous application of NGF was suggested as a promising therapeutic strategy for traumatic and neurodegenerative diseases, however effective delivery of NGF into the CNS parenchyma is still challenging due mainly to its limited ability to cross the blood–brain barrier, and intolerable side effects if administered into the brain ventricular system. An effective method to ensure delivery of NGF into the parenchyma of CNS is the genetic modification of NSC to overexpress NGF gene. Overexpression of NGF in adult human OBNSC is expected to alter their proliferation and differentiation nature, and thus might enhance their therapeutic potential. In this study, we genetically modified adult human OBNS/PC to overexpress human NGF (hNGF) and green fluorescent protein (GFP) genes to provide insight about the effects of hNGF and GFP genes overexpression in adult human OBNS/PC on their in vitro multipotentiality using DNA microarray, immunophenotyping, and Western blot (WB) protocols. Our analysis revealed that OBNS/PC-GFP and OBNS/PC-GFP-hNGF differentiation is a multifaceted process involving changes in major biological processes as reflected in alteration of the gene expression levels of crucial markers such as cell cycle and survival markers, stemness markers, and differentiation markers. The differentiation of both cell classes was also associated with modulations of key signaling pathways such MAPK signaling pathway, ErbB signaling pathway, and neuroactive ligand-receptor interaction pathway for OBNS/PC-GFP, and axon guidance, calcium channel, voltage-dependent, gamma subunit 7 for OBNS/PC-GFP-hNGF as revealed by GO and KEGG. Differentiated OBNS/PC-GFP-hNGF displayed extensively branched cytoplasmic processes, a significant faster growth rate and up modulated the expression of oligodendroglia precursor cells markers (PDGFRα, NG2 and CNPase) respect to OBNS/PC-GFP counterparts. These findings suggest an enhanced proliferation and oligodendrocytic differentiation potential for OBNS/PC-GFP-hNGF as compared to OBNS/PC-GFP.

English

CT being the primary modality of choice in many centers for the diagnosis of brain pathology, normal brain ventricular size measurements is an important parameter for the diagnosis of conditions like hydrocephalus, age related atrophic changes and also other brain pathologies producing ventriculomegaly. It is also important for knowing the normal upper and lower limits of the brain ventricular system in the different age groups, and in both sexes so as to diagnose brain pathology.The ventricular system of the brain undergoes changes with aging and varies with gender.Our study consists of 48 female, and 64 male patients. Apart from the ventricular measurements, two ratios and two indices were also calculated - which included the right and left Evan's ratio, CM index, and ventricular size index.

An Assay for Permeability of the Zebrafish Embryonic Neuroepithelium

The brain ventricular system is conserved among vertebrates and is composed of a series of interconnected cavities called brain ventricles, which form during the earliest stages of brain development and are maintained throughout the animal's life. The brain ventricular system is found in vertebrates, and the ventricles develop after neural tube formation, when the central lumen fills with cerebrospinal fluid (CSF) (1,2). CSF is a protein rich fluid that is essential for normal brain development and function(3-6). In zebrafish, brain ventricle inflation begins at approximately 18 hr post fertilization (hpf), after the neural tube is closed. Multiple processes are associated with brain ventricle formation, including formation of a neuroepithelium, tight junction formation that regulates permeability and CSF production. We showed that the Na,K-ATPase is required for brain ventricle inflation, impacting all these processes (7,8), while claudin 5a is necessary for tight junction formation (9). Additionally, we showed that "relaxation" of the embryonic neuroepithelium, via inhibition of myosin, is associated with brain ventricle inflation. To investigate the regulation of permeability during zebrafish brain ventricle inflation, we developed a ventricular dye retention assay. This method uses brain ventricle injection in a living zebrafish embryo, a technique previously developed in our lab(10), to fluorescently label the cerebrospinal fluid. Embryos are then imaged over time as the fluorescent dye moves through the brain ventricles and neuroepithelium. The distance the dye front moves away from the basal (non-luminal) side of the neuroepithelium over time is quantified and is a measure of neuroepithelial permeability (Figure 1). We observe that dyes 70 kDa and smaller will move through the neuroepithelium and can be detected outside the embryonic zebrafish brain at 24 hpf (Figure 2). This dye retention assay can be used to analyze neuroepithelial permeability in a variety of different genetic backgrounds, at different times during development, and after environmental perturbations. It may also be useful in examining pathological accumulation of CSF. Overall, this technique allows investigators to analyze the role and regulation of permeability during development and disease.

Some aspects of purinergic signaling in the ventricular system of porcine brain

BackgroundNumerous signaling pathways function in the brain ventricular system, including the most important - GABAergic, glutaminergic and dopaminergic signaling. Purinergic signalization system - comprising nucleotide receptors, nucleotidases, ATP and adenosine and their degradation products - are also present in the brain. However, the precise role of nucleotide signalling pathway in the ventricular system has been not elucidated so far. The aim of our research was the identification of all three elements of purinergic signaling pathway in the porcine brain ventricular system.ResultsBesides nucleotide receptors on the ependymocytes surface, we studied purines and pyrimidines in the CSF, including mechanisms of nucleotide signaling in the swine model (Sus scrofa domestica). The results indicate presence of G proteins coupled P2Y receptors on ependymocytes and also P2X receptors engaged in fast signal transmission. Additionally we found in CSF nucleotides and adenosine in the concentration sufficient to P receptors activation. These extracellular nucleotides are metabolised by adenylate kinase and nucleotidases from at least two families: NTPDases and NPPases. A low activity of these nucleotide metabolising enzymes maintains nucleotides concentration in ventricular system in micromolar range. ATP is degraded into adenosine and inosine.ConclusionsOur results confirm the thesis about cross-talking between brain and ventricular system functioning in physiological as well as pathological conditions. The close interaction of brain and ventricular system may elicit changes in qualitative and quantitative composition of purines and pyrimidines in CSF. These changes can be dependent on the physiological state of brain, including pathological processes in CNS.

Gait disorder in older adults

In normal pressure hydrocephalus (NPH), there is enlargement of the brain's ventricular system due to an excess of cerebrospinal fluid. The triad of symptoms in NPH are gait disorder, cognitive impairment, and urinary continence problems. NPs need to consider the possibility of NPH in older adults with a hypokinetic gait.

Intracranial Pressure and Pulsatility Index

Idiopathic Normal Pressure Hydrocephalus (INPH) is a condition affecting gait, cognition and continence. Radiological examination reveals enlarged ventricles of the brain. A shunt that drains CSF from the ventricles to the abdomen often improves the symptoms. Much research on INPH has been focused on identifying tests that predict the outcome after shunt surgery. As part of this quest, there are attempts to find measurement methods of intracranial parameters that are valid, reliable, tolerable and safe for patients.Today's technologies for intracranial pressure (ICP) measurement are invasive, often requiring a burr-hole in the skull. Recently, a method for non-invasive ICP measurements was suggested: the Pulsatile Index (PI) calculated from transcranial Doppler data assessed from the middle cerebral artery. In this thesis the relation between PI and ICP was explored in INPH patients during controlled ICP regulation by lumbar infusion. The confidence interval for predicted ICP, based on measured PI was too large for the method to be of clinical utility.In the quest for better predictive tests for shunt success in INPH, recent studies have shown promising results with criteria based on cardiac related ICP wave amplitudes. The brain ventricular system, and the fluid surrounding the spinal cord are in contact. In this thesis it was shown that ICP waves could be measured via lumbar subarachnoid space, with a slight underestimation.One of the cardinal symptoms of hydrocephalus is cognitive impairment. Neuropsychological studies have demonstrated cognitive tests that are impaired and improve after shunt surgery in INPH patients. However, there is currently no standardized test battery and different studies use different tests. In response, in this thesis a fully automated computerized neuropsychological test battery was developed. The validity, reliability, responsiveness to improvement after shunt surgery and feasibility for testing INPH patients was demonstrated. It was also demonstrated that INPH patients were impaired in all subtests, compared to healthy elderly.

Automatic Model-guided Segmentation of the Human Brain Ventricular System From CT Images

Accurate segmentation of the brain ventricular system on computed tomographic (CT) imaging is useful in neurodiagnosis and neurosurgery. Manual segmentation is time consuming, usually not reproducible, and subjective. Because of image noise, low contrast between soft tissues, large interslice distance, large shape, and size variations of the ventricular system, no automatic method is presently available. The authors propose a model-guided method for the automated segmentation of the ventricular system. Fifty CT scans of patients with strokes at different sites were collected for this study. Given a brain CT image, its ventricular system was segmented in five steps: (1) a predefined volumetric model was registered (or deformed) onto the image; (2) according to the deformed model, eight regions of interest were automatically specified; (3) the intensity threshold of cerebrospinal fluid was calculated in a region of interest and used to segment all regions of cerebrospinal fluid from the entire brain volume; (4) each ventricle was segmented in its specified region of interest; and (5) intraventricular calcification regions were identified to refine the ventricular segmentation. Compared to ground truths provided by experts, the segmentation results of this method achieved an average overlap ratio of 85% for the entire ventricular system. On a desktop personal computer with a dual-core central processing unit running at 2.13 GHz, about 10 seconds were required to analyze each data set. Experiments with clinical CT images showed that the proposed method can generate acceptable results in the presence of image noise, large shape, and size variations of the ventricular system, and therefore it is potentially useful for the quantitative interpretation of CT images in neurodiagnosis and neurosurgery.

CNS-targeted LIF Expression Improves Therapeutic Efficacy and Limits Autoimmune-mediated Demyelination in a Model of Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS) with an inflammatory and a neurodegenerative component. The neuropoietic cytokine leukemia inhibitory factor (LIF) is expressed in MS lesions, but its effect on lesion development is far from understood. LIF is an interesting candidate for MS therapy, as it has neuroprotective properties and may also promote the survival of myelinating oligodendrocytes (OLGs). However, therapeutic administration of LIF is complicated by its limited ability to cross the blood-brain barrier and its pleiotropic actions outside the CNS. In this study, lentiviral vectors (LVs) were used to achieve stable expression and secretion of LIF in the CNS of adult mice. CNS-targeted expression of LIF significantly reduced demyelination in a murine model of MS. In addition, local expression of LIF ameliorated clinical symptoms with enhanced efficacy compared to systemic treatment with recombinant protein. These findings demonstrate that gene therapeutic administration of LIF is a promising approach to limit lesion burden and clinical symptoms in neuroinflammatory disease.

A milestone in three millennia of epileptology--the centenary of the International League against Epilepsy

In 2009, the International League against Epilepsy celebrated a milestone, the centenary of its inauguration. Nonetheless, it is still a relative newcomer in the 3000 year saga of recorded human epilepsy (Temkin, 1971), and one may wonder why the League should have appeared when it did, what its purpose was and what it has achieved? Over much of the past three millennia, epilepsy has been interpreted either as the result of supernatural interventions of various kinds or as a medical illness whose scientific basis was elusive. Until relatively recently, generalized tonic–clonic convulsive seizures were regarded as the essential manifestation of epilepsy, although minor, non-convulsive or locally convulsive phenomena, sometimes associated with generalized convulsive seizures, were known. Such seizures nearly always occur unpredictably, usually suddenly, have spectacular manifestations and cause temporary yet total interruption of consciousness and loss of bodily function control. It is easy to understand why such phenomena would seem to observers as fearful and disgusting events imposed on unwilling sufferers by extrinsic supernatural agencies, and why the sufferer would often be regarded with suspicion and repulsion rather than with sympathy. From such a background, the present-day scientific understanding of epilepsy had to emerge, slowly. The first assertion that epilepsy was ‘a disease like any other’, and not of supernatural origin, appeared in the Hippocratic writing On the sacred disease , dating from ca .400 BC. The Hippocratic author ingeniously explained the pathogenesis of seizures in terms of cold phlegm from the brain suddenly entering the veins and obstructing the ‘pneuma’, a set of concepts quite foreign to present day thought. In the second century AD, Galen attempted another primitive scientific interpretation of the pathogenesis of convulsive seizures, based on the idea that cerebral function resided in the cavities of the brain's ventricular system. He attributed seizures to a …

Automatic Segmentation of the Human Brain Ventricles from MR Images by Knowledge-Based Region Growing and Trimming

Automatic segmentation of the human brain ventricular system from MR images is useful in studies of brain anatomy and its diseases. Existing intensity-based segmentation methods are adaptive to large shape and size variations of the ventricular system, but may leak to the non-ventricular regions due to the non-homogeneity, noise and partial volume effect in the images. Deformable model-based methods are more robust to noise and alleviate the leakage problem, but may generate wrong results when the shape or size of the ventricle to be segmented in the images has a large difference in comparison to its model. In this paper, we propose a knowledge-based region growing and trimming approach where: (1) a model of a ventricular system is used to define regions of interest (ROI) for the four ventricles (i.e., left, right, third and fourth); (2) to segment a ventricle in its ROI, a region growing procedure is first applied to obtain a connected region that contains the ventricle, and (3) a region trimming procedure is then employed to trim the non-ventricle regions. A hysteretic thresholding is developed for the region growing procedure to cope with the partial volume effect and minimize non-ventricular regions. The domain knowledge on the shape and intensity features of the ventricular system is used for the region trimming procedure. Due to the joint use of the model-based and intensity-based approaches, our method is robust to noise and large shape and size variations. Experiments on 18 simulated and 58 clinical MR images show that the proposed approach is able to segment the ventricular system accurately with the dice similarity coefficient ranging from 91% to 99%.

Maintaining CSF drainage at external ventricular drains may help prevent catheter-related infections

Sir, We read with interest the comprehensive study by Hoefnagel et al. [1] entitled “Risk factors for infections related to external ventricular drainage”. Indeed, among various forms of intracranial pressure (ICP) monitors, ventriculostomy remains unique and the most ideal [2, 3]. It provides the neurosurgeon the option of therapeutic cerebrospinal fluid (CSF) drainage in addition to routine ICP monitoring [2]. The enthusiasm for the use of external ventricular drains (EVD) has unfortunately been tempered by the increased risk of ventriculomeningitis [2]. Long-standing controversy exists about the risk factors of developing ventriculostomy-related infections. Hemorrhagic CSF, extended duration of ventriculostomy, catheter manipulation and previous craniotomy, as well as many other factors, have been proven to increase the rate of infections [1–5]. We have observed in our ICU patients that those with pure ICP monitors without temporary drainage are infected more frequently and sooner than those for whom CSF drainage is maintained at least temporarily. A few studies have pointed controversially to the same issue. Smith and Alksne [5] suggested that the use of the ventriculostomy as an EVD rather than an ICP monitor may predispose the patient to CSF infection. However, Schultz et al. [4] and Mayhall et al. [3] found no such association between CSF drainage and an increased risk of infection. Retrospective analysis of our data (unpublished) has revealed a higher rate of infection in pure ICP monitors. Such controversy may be due to the interference of confounding factors, many of which have or have not been found causative in different studies. In biologic fluid-filled systems associated with the risk of microbial contamination, obstruction to flow has been long known to be associated with stasis and infection. This is evident in the case of urinary tract infections and cholangitis. This condition does not occur in isolated body compartments such as the heart or brain ventricular system. However, when such closed systems are exposed to the threat of ascending bacterial infections in the setting of external diversion of CSF flow (EVDs), then the rules will apply. Maintenance of CSF drainage in EVDs (as opposed to pure ICP monitors) counteracts stasis, which may be effective in preventing ascending ventriculostomy-related infections.