Cerebrospinal fluid dynamics in idiopathic normal pressure hydrocephalus on four-dimensional flow imaging.

OBJECTIVES: To evaluate complex CSF movements and shear stress in patients with idiopathic normal pressure hydrocephalus (iNPH) on four-dimensional (4D) flow MRI. METHODS: Three-dimensional velocities and volumes of the reciprocating CSF movements through 12 ROIs from the foramen of Monro to the upper cervical spine were measured in 41 patients with iNPH, 23 patients with co-occurrence of iNPH and Alzheimer's disease (AD), and 9 age-matched controls, using 4D flow imaging and application. Stroke volume, reversed-flow rate, and shear stress were automatically calculated. Relationships between flow-related parameters and morphological measurements were also assessed. RESULTS: Stroke volumes, reversed-flow rates, and shear stress at the cerebral aqueduct were significantly higher in patients with iNPH than in controls. Patients with pure iNPH had significantly higher shear stress at the ventral aspect of the cerebral aqueduct than those with co-occurrence of iNPH and AD. The stroke volume at the upper end of the cerebral aqueduct had the strongest association with the anteroposterior diameter of the lower end of the cerebral aqueduct (r = 0.52). The stroke volume at the foramen of Monro had significant associations with the indices specific to iNPH. The shear stress at the dorsal aspect of the cerebral aqueduct had the strongest association with the diameter of the foramen of Magendie (r = 0.52). CONCLUSIONS: Stroke volumes, reversed-flow rates, and shear stress through the cerebral aqueduct on 4D flow MRI are useful parameters for iNPH diagnosis. These findings can aid in elucidating the mechanism of ventricular enlargement in iNPH. KEY POINTS: • The CSF stroke volume and bimodal shear stress at the cerebral aqueduct were considerably higher in patients with iNPH. • The patients with pure iNPH had significantly higher shear stress at the ventral aspect of the cerebral aqueduct than those with co-occurrence of iNPH and AD. • The shear stress at the cerebral aqueduct was significantly associated with the diameter of the foramen of Magendie.

Intradural pathology and pathophysiology associated with Chiari I malformation in children and adults with and without syringomyelia.

OBJECTIVE The pathophysiology underlying tonsillar herniation and CSF obstruction in Chiari malformation Type I (CM-I) is unclear, and the cause of CM-I-associated syringomyelia is not well understood. A better understanding of this pathophysiology is important for an improved treatment strategy. Therefore, the authors sought to identify, characterize, and examine the intradural pathology and CSF flow pathophysiology in the posterior fossa and at the level of the foramen magnum that occurs in the setting of CM-I. They determined the incidence of these intradural findings and assessed differences across age, with the degree of tonsillar herniation, and in the presence and absence of syringomyelia. METHODS A prospective database initiated in March 2003 recorded all intraoperative findings during surgical treatment of children and adults with CM-I with or without syringomyelia. A total of 389 surgeries for CM-I were performed in 379 patients between March 2003 and June 2016. A total of 109 surgeries were performed in 109 patients with CM-I (without osseoligamentous abnormalities) in whom both a posterior fossa extradural and intradural decompression with duraplasty was performed (first-time intradural procedures). Using a surgical microscope, intradural pathology and obstruction of CSF channels were identified and assessed. Student t-tests and Fisher's exact tests compared groups in a series of univariate analyses, followed by multivariate logistic regression. RESULTS The following intradural pathological entities were observed (prevalence noted in parentheses). These include those that did not obstruct CSF flow channels: opacified arachnoid (33.0%), thickened arachnoid (3.7%), ischemic and gliotic tonsils (40.4%), tonsillar cysts (0.9%), and inferior descent of the fourth ventricle and cervicomedullary junction (CMJ) (78.0%). The following intradural pathological entities were observed to obstruct CSF flow channels: medialized tonsils (100%), tonsil overlying and obstructing the foramen of Magendie (21.1%), intertonsillar and tonsil to CMJ arachnoid adhesions (85.3%), vermian posterior inferior cerebellar artery branches obstructing the foramen of Magendie (43.1%), and arachnoid veils or webs obstructing or occluding the foramen of Magendie (52.3%). Arachnoid veils varied in type and were observed in 59.5% of patients with CM-I who had syringomyelia, which was significantly greater than the 33.3% of patients with CM-I without syringomyelia who had an arachnoid veil (p = 0.018). The presence of CM-I with an arachnoid veil had 3.22 times the odds (p = 0.013, 95% CI 1.29-8.07, by multivariate logistic regression) of being associated with syringomyelia, adjusting for tonsillar herniation. The inferior descent of the fourth ventricle and CMJ occurred with a greater degree of tonsillar herniation (p < 0.001) and correlated with a cervicomedullary kink or buckle on preoperative MRI. CONCLUSIONS Intradural pathology associated with CM-I with or without syringomyelia exists in many forms, is more prevalent than previously recognized in patients of all ages, and may play a role in the pathophysiology of CM-I tonsillar herniation. Arachnoid veils appear to partially obstruct CSF flow, are significantly more prevalent in cases of CM-I with syringomyelia, and therefore may play a role in the pathophysiology of CM-I-associated syringomyelia.

Frequency and long-term follow-up of trapped fourth ventricle following neonatal posthemorrhagic hydrocephalus.

OBJECTIVE Intraventricular hemorrhage (IVH) is a common complication of premature neonates with small birth weight, which often leads to hydrocephalus and treatment with ventriculoperitoneal (VP) shunting procedures. Trapped fourth ventricle (TFV) can be a devastating consequence of the subsequent occlusion of the cerebral aqueduct and foramina of Luschka and Magendie. METHODS The authors retrospectively reviewed 8 consecutive cases involving pediatric patients with TFV following VP shunting for IVH due to prematurity between 2003 and 2012. The patients ranged in gestational age from 23.0 to 32.0 weeks, with an average age at first shunting procedure of 6.1 weeks (range 3.1-12.7 weeks). Three patients were managed with surgery. Patients received long-term radiographic (mean 7.1 years; range 3.4-12.2 years) and clinical (mean 7.8 years; range 4.6-12.2 years) follow-up. RESULTS The frequency of TFV following VP shunting for neonatal posthemorrhagic hydrocephalus was found to be 15.4%. Three (37.5%) patients presented with symptoms of posterior fossa compression and were treated surgically. All of these patients showed signs of radiographic improvement with stable or improved clinical examinations during postoperative follow-up. Of the 5 patients treated conservatively, 80% experienced stable ventricular size and 1 patient experienced a slight increase (3 mm) on imaging. All of the nonsurgical patients showed stable to improved clinical examinations over the follow-up period. CONCLUSIONS The frequency of TFV among premature IVH patients is relatively high. Most patients with TFV are asymptomatic at presentation and can be managed without surgery. Symptomatic patients may be treated surgically for decompression of the fourth ventricle.

Two-year-old with post-surgical hypoglossal nerve injury and obstructive sleep apnea.

BACKGROUND: Airway patency in both children and adults depends on the tonic and phasic activation of muscles of the tongue and pharynx supplied by the hypoglossal nerve arising at the medullary level. METHODS/PATIENT: We report a case of a 2-year-old who after resection of fourth ventricle anaplastic ependymoma developed severe sleep disordered breathing and tongue fasciculation. RESULTS: Polysomnography showed severe obstructive sleep apnea with oxygen desaturation to 33%. Magnetic resonance imaging of the brain showed post-surgical effacement of the dorsal lateral medulla. CONCLUSIONS: We postulate that damage to the hypoglossal nerve at the level of the medulla contributed to the patient's severe obstructive sleep apnea. Patient was treated with tracheostomy.

Comparing fourth ventricle shunt survival after placement via stereotactic transtentorial and suboccipital approaches.

OBJECT: Fourth ventricle hydrocephalus, or a "trapped" fourth ventricle, presents a treatment challenge in pediatric neurosurgery. Fourth ventricle hydrocephalus develops most commonly as a result of congenital anomalies, intraventricular hemorrhage, or infection. Standard management of loculated fourth ventricle hydrocephalus consists of fourth ventricle shunt placement via a suboccipital approach. An alternative approach is stereotactic-guided transtentorial fourth ventricle shunt placement via the nondominant superior parietal lobule. In this report, the authors compare shunt survival after placement via the suboccipital and stereotactic parietal transtentorial (SPT) approaches. METHODS: A retrospective chart review was performed to find all patients with a fourth ventricle shunt placed between January 1, 1998, and December 31, 2011. Time to shunt failure was quantified as the number of days from shunt placement to first shunt revision or removal. Other variables studied included patient age and sex, origin of hydrocephalus, comorbidities, number of existing supratentorial catheters at the time of fourth ventricle shunt placement (as a proxy for complexity), operating surgeon, and number of previous shunt revisions. The crossover rate from one technique to the other after shunt failure from the original approach was also investigated. RESULTS: In the 29 fourth ventricle shunts placed during the study period, 18 were placed via the suboccipital approach (62.1%) and 11 via the SPT approach (37.9%). There was a statistically significant difference in time to shunt failure, with the SPT shunts lasting an average of 901 days and suboccipital shunts lasting 122 days (p = 0.04). In addition, there was a significant difference in the rate of crossover from one technique to another, with 1 SPT shunt changed to a suboccipital shunt (5.6%) and 5 suboccipital shunts changed to SPT shunts (45.5%). CONCLUSIONS: Fourth ventricle shunt placement using an SPT approach resulted in significantly longer shunt survival times and lower rates of revision than the traditional suboccipital approach, despite a higher rate of crossover from previously failed shunting procedures. Stereotactic parietal transtentorial shunt placement may be considered for patients with loculated fourth ventricle hydrocephalus, especially when shunt placement via the standard suboccipital approach fails. It is therefore reasonable to offer this procedure either as a first option for the treatment of fourth ventricle hydrocephalus or when the need for fourth ventricle shunt revision arises.

Neonatal hemifacial spasm and fourth ventricle mass.

Congential hemifacial spasm is a rare condition that is characterized by the occurrence of paroxysmal hemifacial contractions in neonates. We review the clinical, neurophysiological, neuroimaging, and histopathological findings, as well as the differential diagnosis, therapeutic approach, and outcome of all the described cases. Moreover, we report two new cases including the ictal video-electroencephalography recordings. Hemifacial spasm starts early in life, and is characterized by unilateral, involuntary, irregular tonic or clonic contractions of muscles innervated by the seventh cranial nerve. Hemifacial spasm is associated with eyelid blinking, and sometimes with breathing irregularities, hyperventilation, and/or other neurological manifestations (dystonic movements, nystagmus). Interictal and ictal video-electroencephalography did not reveal epileptiform abnormalities. In all cases, brain magnetic resonance imaging showed a mass involving the cerebellar peduncle, the cerebellar hemisphere, or the floor of the fourth ventricle. The semiology of the paroxysmal attacks is probably due to the activation of cranial nerve nuclei through intralesional hypersynchronous discharges, as shown by the intraoperative recordings and functional brain imaging described in the literature. We point out the importance of identifying such seizures in order to make an early diagnosis of the underlying cerebral lesion.

Disproportionately large communicating fourth ventricle associated with syringomyelia and intradural arachnoid cyst in the spinal cord successfully treated with additional shunting. Case report.

A 44-year-old woman presented with a rare case of disproportionately large communicating fourth ventricle (DLCFV) associated with syringomyelia and intradural arachnoid cyst in the spinal cord. Ventriculoperitoneal shunt operation was performed for hydrocephalus after subarachnoid hemorrhage. She developed DLCFV, which was then associated with syringomyelia and spinal intradural arachnoid cyst. Shunting of the fourth ventricle improved DLCFV, and then the syringomyelia and arachnoid cyst. Although the aqueduct was patent, independent pressure control of the fourth ventricle and the other ventricles was necessary to improve the symptoms. Shunting of the fourth ventricle should be considered for patients with DLCFV when the symptoms persist despite adequate pressure control of the other ventricles.

Sidestream cigarette smoke effects on cardiovascular responses in conscious rats: involvement of oxidative stress in the fourth cerebral ventricle.

BACKGROUND: Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS). METHODS: We evaluated males Wistar rats (320-370 g), which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm). Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 µg/kg, bolus) to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 µg/kg, bolus) to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 µL) injection into the 4th V. RESULTS: Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes. CONCLUSION: We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity.

Involvement of the extracellular signal-regulated kinase 1/2 signaling pathway in amylin's eating inhibitory effect.

Peripheral amylin inhibits eating via the area postrema (AP). Because amylin activates the extracellular-signal regulated kinase 1/2 (ERK) pathway in some tissues, and because ERK1/2 phosphorylation (pERK) leads to acute neuronal responses, we postulated that it may be involved in amylin's eating inhibitory effect. Amylin-induced ERK phosphorylation (pERK) was investigated by immunohistochemistry in brain sections containing the AP. pERK-positive AP neurons were double-stained for the calcitonin 1a/b receptor, which is part of the functional amylin-receptor. AP sections were also phenotyped using dopamine-ß-hydroxylase (DBH) as a marker of noradrenergic neurons. The effect of fourth ventricular administration of the ERK cascade blocker U0126 on amylin's eating inhibitory action was tested in feeding trials. The number of pERK-positive neurons in the AP was highest ∼10-15 min after amylin treatment; the effect appeared to be dose-dependent (5-20 µg/kg amylin). A portion of pERK-positive neurons in the AP carried the amylin-receptor and 22% of the pERK-positive neurons were noradrenergic. Pretreatment of rats with U0126 decreased the number of pERK-positive neurons in the AP after amylin injection. U0126 also attenuated the ability of amylin to reduce eating, at least when the animals had been fasted 24 h prior to the feeding trial. Overall, our results suggest that amylin directly stimulates pERK in AP neurons in a time- and dose-dependent manner. Part of the AP neurons displaying pERK were noradrenergic. At least under fasting conditions, pERK was shown to be a necessary part in the signaling cascade mediating amylin's anorectic effect.

Disorders affecting the fourth ventricle: etiology and clinical correlates.

OBJECTIVE: The fourth ventricle encompasses many vital structures including the brainstem as its floor and the cerebellum as its lateral wall and roof. Therefore, lesions affecting the fourth ventricle may present as cerebellar or brainstem manifestations. Herein, we presented our experience in the diagnosis of disorders affecting the fourth ventricle during the past 15 years. STUDY DESIGN: Retrospective study. SETTING: University hospital. SUBJECTS: From September 1995 to August 2010, 24,838 patients with vertigo/dizziness visited the clinic. Of them, 13 patients (0.5%) had tumor/stroke affecting the fourth ventricle. MAIN OUTCOME MEASURES: All patients underwent a battery of audiovestibular function test. RESULTS: All patients had vertigo (100%) and then ataxia (92%) and nausea/vomiting (85%). Eight patients (68%) displayed persistent nystagmus. Most (>75%) patients showed central signs in electronystagmographic recordings and abnormal caloric coupled with visual suppression test. Three patients underwent both ocular and cervical vestibular-evoked myogenic potential tests, and abnormal results were noted in all 3 patients indicating a brainstem involvement. However, magnetic resonance imaging failed to demonstrate brainstem lesion in these 3 patients. Final diagnoses consisted of the following: cavernoma, n = 3; metastatic cancer, n = 3; astrocytoma, n = 2; meningioma, n = 2; epidermoid cyst, n = 1; ependymoma, n = 1; and lymphoma, n = 1. The prognosis was poor as 10 patients (77%) died within 2 years. CONCLUSION: When a vertiginous patient displayed ataxia, persistent vomiting, and persistent nystagmus, lesion affecting the fourth ventricle should be kept in mind because its prognosis is poor. Abnormal results in electronystagmography and in ocular and cervical vestibular-evoked myogenic potentials may serve as a supplementary to magnetic resonance imaging to delineate the involvement of the lesion.

Alterations of pulsation absorber characteristics in experimental hydrocephalus.

OBJECT: Analysis of waveform data in previous studies suggests that the pulsatile movement of CSF may play a role in attenuating strong arterial pulsations entering the cranium, and its effectiveness in attenuating these pulsations may be altered by changes in intracranial pressure (ICP). These findings were obtained in studies performed in canines with normal anatomy of the CSF spaces. How then would pulsation absorbance respond to changes in CSF movement under obstructive conditions such as the development of hydrocephalus? In the present study, chronic obstructive hydrocephalus was induced by the injection of cyanoacrylate gel into the fourth ventricle of canines, and pulsation absorbance was compared before and after hydrocephalus induction. METHODS: Five animals were evaluated with simultaneous recordings of ICP and arterial blood pressure (ABP) before and at 4 and 12 weeks after fourth ventricle obstruction by cyanoacrylate. To assess how the intracranial system responds to the arterial pulsatile component, ABP and ICP waveforms recorded in a time domain had to be analyzed in a frequency domain. In an earlier study the authors introduced a particular technique that allows characterization of the intracranial system in the frequency domain with sufficient accuracy and efficiency. This same method was used to analyze the relationship between ABP and ICP waveforms recorded during several acute states including hyperventilation as well as CSF withdrawal and infusion under conditions before and after inducing chronic obstructive hydrocephalus. Such a relationship is reflected in terms of a gain, which is a function of frequency. The cardiac pulsation absorbance (CPA) index, which is simply derived from a gain evaluated at the cardiac frequency, was used to quantitatively evaluate the changes in pulsation absorber function associated with the development of hydrocephalus within each of the animals, which did become hydrocephalic. To account for normal and hydrocephalic conditions within the same animal and at multiple time points, statistical analysis was performed by repeated-measures ANOVA. RESULTS: The performance of the pulsation absorber as assessed by CPA significantly deteriorated after the development of chronic hydrocephalus. In these animals the decrement in CPA was far more significant than other anticipated changes including those in ICP, compliance, or ICP pulse amplitude. CONCLUSIONS: To the extent that the free CSF movement acts as a buffer of arterial pulsation input to flow in microvessels, alterations in the pulsation absorber may play a pathophysiological role. One measure of alterations in the way the brain deals with pulsatile input-the CPA measurement-changes dramatically with the imposition of hydrocephalus. Results in the present study suggest that CPA may serve as a complementary metric to the conventional static measure of intracranial compliance in other experimental and clinical studies.

Ependymal alterations in sudden intrauterine unexplained death and sudden infant death syndrome: possible primary consequence of prenatal exposure to cigarette smoking.

BACKGROUND: The ependyma, the lining providing a protective barrier and filtration system separating brain parenchyma from cerebrospinal fluid, is still inadequately understood in humans. In this study we aimed to define, by morphological and immunohistochemical methods, the sequence of developmental steps of the human ependyma in the brainstem (ventricular ependyma) and thoracic spinal cord (central canal ependyma) of a large sample of fetal and infant death victims, aged from 17 gestational weeks to 8 postnatal months. Additionally, we investigated a possible link between alterations of this structure, sudden unexplained fetal and infant death and maternal smoking. RESULTS: Our results demonstrate that in early fetal life the human ependyma shows a pseudostratified cytoarchitecture including many tanycytes and ciliated cells together with numerous apoptotic and reactive astrocytes in the subependymal layer. The ependyma is fully differentiated, with a monolayer of uniform cells, after 32 to 34 gestational weeks. We observed a wide spectrum of ependymal pathological changes in sudden death victims, such as desquamation, clusters of ependymal cells in the subventricular zone, radial glial cells, and the unusual presence of neurons within and over the ependymal lining. These alterations were significantly related to maternal smoking in pregnancy. CONCLUSIONS: We conclude that in smoking mothers, nicotine and its derivatives easily reach the cerebrospinal fluid in the fetus, immediately causing ependymal damage. Consequently, we suggest that the ependyma should be examined in-depth first in victims of sudden fetal or infant death with mothers who smoke.

Simplified aqueductal stenting for isolated fourth ventricle using a small-caliber flexible endoscope in a patient with neurococcidiomycosis: technical case report.

OBJECTIVE: Endoscopic aqueductoplasty and stenting are a preferred treatment for isolated fourth ventricle syndrome related to membranous aqueductal obstruction. We describe a technique using a small-caliber flexible endoscope that may address some limitations of current strategies. CLINICAL PRESENTATION: A 39-year-old woman with hydrocephalus caused by neurococcidiomycosis and a functional right frontal ventriculoperitoneal shunt presented with vomiting and an isolated fourth ventricle. Magnetic resonance imaging showed an enlarged fourth ventricle and exuberant basilar arachnoiditis obstructing the outlet foramina of the fourth ventricle. Ventriculography indicated aqueductal obstruction. INTERVENTION: Aqueductoplasty was planned to allow spinal fluid to flow from the fourth ventricle to the ventriculoperitoneal shunt. A stent-endoscope construct was prepared by feeding a flexible endoscope through a ventricular catheter cut 4 cm from the tip. The flexible endoscope was contoured to fit the anatomy of the aqueduct. Uncomplicated aqueductoplasty was performed through a single left frontal burr hole using the stent-endoscope construct to perforate a membranous veil and inspect the fourth ventricle. The stent was deployed over the endoscope using the proximal end of the catheter to deliver and secure the stent as the endoscope was withdrawn. CONCLUSION: Aqueductoplasty and stenting using a small-caliber flexible endoscope is feasible. The endoscope can be contoured to suit the anatomy of the aqueduct and improves visualization of the leading edge of the stent during deployment. Furthermore, when the endoscope is used to create the perforation, the target is not obscured by the shaft of the device used to make the perforation.

Subarachnoid hemorrhage caused by ruptured dissecting aneurysm arising from the extracranial distal posterior inferior cerebellar artery--case report.

A 50-year-old man presented with a dissecting aneurysm arising from the extracranial portion of the right posterior inferior cerebellar artery (PICA) causing subarachnoid hemorrhage (SAH) and manifesting as sudden onset of disturbed consciousness. Computed tomography showed SAH with ventricular reflux predominantly in the posterior fossa. Angiography revealed a fusiform aneurysm of the right PICA originating extracranially from the right vertebral artery. The aneurysm was isolated and excised. Histological examination showed dissection of the aneurysm wall. Dissecting aneurysm arising from the extracranial portion of the PICA is extremely rare.

An unusual cause of posterior fossa mass: Lhermitte-Duclos disease.

Lhermitte-Duclos disease (LDD) (dysplastic cerebellar gangliocytoma) is a rare disorder of unknown pathogenesis, presenting with signs and symptoms resulting from obstruction of cerebrospinal fluid flow and mass effect in the posterior fossa. Magnetic resonance imaging is the diagnostic modality of choice allowing preoperative diagnosis with characteristic findings. Surgery is the choice of treatment. The typical histopathological findings of LDD are characterized by widening of the molecular layer, absence of the Purkinje cell layer and hypertrophy in the granule cell layer. Herein we report an adolescent girl with LDD diagnosed preoperatively by the conventional and advanced MR techniques.

Ruptured aneurysms of the choroidal branches of the posterior inferior cerebellar artery: a review of the literature and a case report.

Aneurysms of the choroidal branches of the posterior inferior cerebellar artery (PICA) are quite rare; only seven such cases have been reported thus far. In this study, we present a very rare case of a ruptured aneurysm of a choroidal branch of the PICA; the aneurysm was exposed by splitting the vermis and resected after proximal arterial ligation. We have also undertaken a thorough review of the literature on aneurysms in choroidal branches of the PICA, focusing on the clinical presentation, etiology, radiological findings, and surgical strategies. We found that the aneurysms in our patient and the aneurysms in seven published case reports were small, and frequently associated with vascular anomalies. Intraventricular hemorrhage (IVH) in the fourth ventricle was detected in all eight cases. The outcomes of surgical treatment were generally favorable, notwithstanding the high incidence of rebleeding after rupture of distal PICA aneurysms. The recognition of predominant fourth ventricular hemorrhage should raise the suspicion of the presence of an underlying aneurysm, and digital subtraction angiograms (DSAs) should be immediately obtained in order to detect small aneurysms of the choroidal branches of the PICA.

Transplantation of cultured choroid plexus epithelial cells via cerebrospinal fluid shows prominent neuroprotective effects against acute ischemic brain injury in the rat.

Choroid plexus (CP) epithelial cells (CPECs) produce cerebrospinal fluid (CSF) to provide the CNS with a specialized microenvironment. Our previous study showed that the conditioned medium of cultured CPECs enhanced the survival and neurite extension of hippocampal neurons. The present study examined the ability of cultured CPECs to protect against ischemic brain injury when transplanted into the CSF. Rats were subjected to a transient occlusion of the middle cerebral artery, followed by an injection of cultured CPECs into the fourth ventricle. The injection markedly reduced neurological deficits and infarction volume within 24h. Other beneficial effects were (1) a reduction in number of apoptotic and inflammatory cells, (2) an up-regulation of the mRNA expression of an anti-apoptotic effecter, cAMP-response element binding protein, and (3) a down-regulation of the production of pro-inflammatory factors such as interleukin-1 beta and inducible nitric oxide synthase. The injected CPECs were located within the ventricles and on the brain's surface, not in the ischemic foci, suggesting that they exert their effects by releasing diffusible neuroprotective factors into the CSF. The transplantation of CPECs via CSF is a potential new strategy for protecting against ischemic brain injury.

Computational macroscopical patterning of the medullary striae of fourth ventricle

The aim of this study was to pattern macroscopically, by use of computational tools, the number and distributionof the medullary striae (MS) of fourth ventricle. After removing 71 fresh human brain stems, each respectiverhomboid fossa was photographed. The MS were carefully identified to be shaped and fulfilled by means ofa digital pen, using the Adobe Photoshop CS3® program. For absolute and relative analyses of number anddistribution, it was considered the maximum and minimum numbers of striae; striae that reached the ipsilaterallateral recess; presence of horizontal or oblique striae, with or without parallelism; and striae located at pontineor bulbar part of the rhomboid fossa. At least two MS per side were macroscopically detectable in 90.6% ofcases; they were bilaterally absent in 5.3% of pieces; and at least one medullary stria was present in both sidesof the rhomboid fossa in 92% of cases. As on the right side (36% of cases) as on the left (26.6%), two MS werefrequently more present. In 60% of cases, striae reached ipsilateral lateral recess on the left, and in 40% of caseson the right. It was detected horizontal, (non-parallel) oblique and parallel striae in 50.7, 86.7 and 26.7%of cases, respectively. Medial medullary striae were observed in the bulbar part of rhomboid fossa in 80% ofpieces, and in 36% of cases in the pontine part. The MS of fourth ventricle show high morphological variabilitydegree in relation to number and distribution.

Intraventricular fibrinolysis and lumbar drainage for ventricular hemorrhage.

BACKGROUND AND PURPOSE: Both intraventricular fibrinolysis (IVF) and lumbar drainage (LD) may reduce the need for exchange of external ventricular drainage (EVD) and shunt surgery in patients with intracerebral hemorrhage and severe intraventricular hemorrhage. We investigated the feasibility and safety of IVF followed by early LD for the treatment of posthemorrhagic hydrocephalus. METHODS: This prospective study included patients with spontaneous ganglionic intracerebral hemorrhage and severe intraventricular hemorrhage with acute obstructive posthemorrhagic hydrocephalus who received an EVD (n=32). The treatment algorithm started with IVF (4 mg recombinant tissue plasminogen activator every 12 hours) until clearance of the third and fourth ventricles from blood. Thereupon, EVD was clamped and if clamping was unsuccessful, communicating posthemorrhagic hydrocephalus was assumed and LD placed. EVD was removed if there was neither an increase of intracranial pressure nor ventricle enlargement on CT. A ventriculoperitoneal shunt was indicated if "LD weaning" was unsuccessful for >10 days. Outcome was assessed at 90 and 180 days using the modified Rankin Scale. RESULTS: IVF resulted in fast clearance of the third and fourth ventricles (73+/-50 hours). However, early EVD removal was only possible in 4 patients. The remaining 28 patients developed communicating posthemorrhagic hydrocephalus. In all of these patients, early LD was capable to replace EVD. EVD exchange was not necessary and EVD duration was 105+/-59 hours. Only one patient required a ventriculoperitoneal shunt. At 180 days, 20 (62.5%) patients had a good (modified Rankin Scale 0 to 3) outcome and 5 (15.6%) patients had died. One patient had asymptomatic ventricular rebleeding. CONCLUSIONS: In patients with secondary intraventricular hemorrhage and posthemorrhagic hydrocephalus, the combined treatment approach of IVF and early LD is safe and feasible, avoids EVD exchange, and may markedly reduce the need for shunt surgery.

Association of Chiari malformation type I and tethered cord syndrome: preliminary results of sectioning filum terminale.

OBJECTIVE: The pathogenesis of CM-I is incompletely understood. We describe an association of CM-I and TCS that occurs in a subset of patients with normal size of the PCF. METHODS: The prevalence of TCS was determined in a consecutively accrued cohort of 2987 patients with CM-I and 289 patients with low-lying cerebellar tonsils (LLCT). Findings in 74 children and 244 adults undergoing SFT were reviewed retrospectively. Posterior cranial fossa size and volume were measured using reconstructed 2D computed tomographic scans and MR images. Results were compared to those in 155 age- and sex-matched healthy control individuals and 280 patients with generic CM-I. The relationships of neural and osseus structures at the CCJ and TLJ were investigated morphometrically on MR images. Intraoperative CDU was used to measure anatomical structures and CSF flow in the lumbar theca. RESULTS: Tethered cord syndrome was present in 408 patients with CM-I (14%) and 182 patients with LLCT (63%). In 318 patients undergoing SFT, there were no significant differences in the size or volume of the PCF as compared to healthy control individuals. Morphometric measurements demonstrated elongation of the brain stem (mean, 8.3 mm; P < .001), downward displacement of the medulla (mean, 4.6 mm; P < .001), and normal position of the CMD except in very young patients. Compared to patients with generic CM-I, the FM was significantly enlarged (P < .001). The FT was typically thin and taut (mean transverse diameter, 0.8 mm). After SFT, the cut ends of the FT distracted widely (mean, 41.7 mm) and CSF flow in the lumbar theca increased from a mean of 0.7 cm/s to a mean of 3.7 cm/s (P < .001). Symptoms were improved or resolved in 69 children (93%) and 203 adults (83%) and unchanged in 5 children (7%) and 39 adults (16%) and, worse, in 2 adults (1%) over a follow-up period of 6 to 27 months (mean, 16.1 months +/- 4.6 SD). Magnetic resonance imaging 1 to 18 months after surgery (mean, 5.7 months +/- 3.8 SD) revealed upward migration of the CMD (mean, 5.1 mm, P < .001), ascent of the cerebellar tonsils (mean, 3.8 mm, P < .001), reduction of brain stem length (mean, 3.9 mm, P < .001), and improvement of scoliosis or syringomyelia in some cases. CONCLUSIONS: Chiari malformation type I/TCS appears to be a unique clinical entity that occurs as a continuum with LLCT/TCS and is distinguished from generic CM-I by enlargement of the FM and the absence of a small PCF. Distinctive features include elongation and downward displacement of the hindbrain, normal position of the CMD, tight FT, and reduced CSF flow in the lumbar theca. There is preliminary evidence that SFT can reverse moderate degrees of tonsillar ectopia and is appropriate treatment for cerebellar ptosis after Chiari surgery in this cohort.