Chiari malformation and spinal interdural cyst: A proposed association and review of the literature.

Background: Interdural cysts are rare meningeal cysts with an unclear etiology. They are often mistaken for other mass lesions, including arachnoid cysts and tumors. Correctly identifying and classifying these cysts, as well as how they have formed in individual patients, are crucial to providing effective treatment options for patients.

Bilateral Thalamic Glioma: A Case Report.

Bilateral thalamic primary gliomas are an exceedingly rare entity. Symptomology heralding a workup and diagnosis of bithalamic gliomas is diverse and varies between the pediatric and adult populations. Herein, we present a case of a 63-year-old female patient who presented with progressive gait imbalance and fatigue, prompting an outpatient brain MRI, remarkable for marked expansion of the bilateral thalami secondary to non-enhancing, T2-weighted-fluid-attenuated inversion recovery (T2-FLAIR) bright bithalamic lesions.

Differential Patterns of Referral to Neurosurgery: A Comparison of Allopathic Physicians, Osteopathic Physicians, Nurse Practitioners, Physician Assistants, and Chiropractors.

Background: Rising cost and limited resources remain major challenges to U.S. health care and neurosurgery in particular.

Triacetin-based acetate supplementation as a chemotherapeutic adjuvant therapy in glioma.

Cancer is associated with epigenetic (i.e., histone hypoacetylation) and metabolic (i.

Treatment of indolent, nonencapsulated cryptococcal meningitis associated with hydrocephalus.

Infection with cryptococcal meningitis is uncommon in immunocompetent patients. The major virulence factor is the polysaccharide capsule, while nonencapsulated mutants are generally considered nonpathogenic. The authors present a case of hydrocephalus caused by meningitis from an indolent, nonencapsulated Cryptococcus sp.

Increased rate of complications on a neurological surgery service after implementation of the Accreditation Council for Graduate Medical Education work-hour restriction.

Object: The Accreditation Council for Graduate Medical Education instituted mandatory 80-hour work-week limitations in July 2003. The work-hour restriction was met with skepticism among the academic neurosurgery community and is thought to represent a barrier to teaching, ultimately compromising patient care. The authors hypothesize that the introduction of the mandatory resident work-hour restriction corresponds with an overall increase in morbidity rate.

Cortical evoked potentials used for placement of a laminotomy lead array: a case report.

Objective: We describe a technique for placement of a cervical spinal cord electrode under general anesthesia using the contacts as cortical evoked potential stimulating electrodes.

Methods: A 37-year-old man required revision of the percutaneous lead of a spinal cord stimulator system placed for right upper extremity pain. A Resume-TL laminotomy lead was inserted at the C5-6 interspace in the prone position under general anesthesia.

Radiographically distinct variant of pilocytic astrocytoma: a case series.

The imaging findings of pilocytic astrocytomas are classically described as a cyst with an enhancing mural nodule. We report 2 unusual cases of multicystic cerebellar midline masses that were proven to be pilocytic astrocytomas. The uniqueness of the imaging features in these cases may represent an important variant of pilocytic astrocytomas.

Use of an artificial neural network to predict head injury outcome.

Object: The authors describe the artificial neural network (ANN) as an innovative and powerful modeling tool that can be increasingly applied to develop predictive models in neurosurgery. They aimed to demonstrate the utility of an ANN in predicting survival following traumatic brain injury and compare its predictive ability with that of regression models and clinicians.

Methods: The authors designed an ANN to predict in-hospital survival following traumatic brain injury.

A case-comparison study of the subdural evacuating port system in treating chronic subdural hematomas.

Object: The Subdural Evacuating Port System (SEPS) was recently introduced as a novel method of treating chronic subdural hematomas (SDHs). This system is a variation of the existing twist-drill craniostomy methods for treating chronic SDH. Compared with craniotomy or bur hole treatment of chronic SDH, this system offers the possibility of treatment at bedside without general anesthesia.

Ca(v)1.2 splice variant with exon 9* is critical for regulation of cerebral artery diameter.

L-type voltage-dependent Ca(2+) channels (VDCCs) are essential for numerous processes in the cardiovascular and nervous systems. Alternative splicing modulates proteomic composition of Ca(v)1.2 to generate functional variation between channel isoforms.

A novel association between a chronic subdural hematoma and a fibrinolytic pathway defect: case report.

Objective: Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage that is known to recur in up to one-fifth of treated patients. We present a patient with recurrent CSDH who was found to have a defect in the fibrinolytic pathway, which may be a novel explanation for recurrent CSDH. This defect, deficiency of plasminogen activator inhibitor type I (PAI-1), should be recognized as a possible cause of CSDH.

A model for idiopathic intracranial hypertension and associated pathological ICP wave-forms.

Idiopathic intracranial hypertension (IIH) is a syndrome of unknown cause characterized by elevated intracranial pressure (ICP). While imaging often reveals a stenosis of the transverse sinuses, the role of this feature in IIH has been in dispute. Many patients with chronic daily headache have been found to actually be suffering from a milder form of IIH without papilledema (IIHWOP).

Modeling intracranial pressures in microgravity: the influence of the blood-brain barrier.

Introduction: A majority of astronauts experience symptoms of headache, vomiting, nausea, lethargy, and gastric discomfort during the first few hours or days after entering a microgravity environment. Due to similarities in symptoms and their time evolution, it has been hypothesized that some of these conflicts are related to the development of benign intracranial hypertension in these individuals in microgravity.

Methods: This hypothesis was tested using a validated mathematical model that embeds the intracranial system in whole-body physiology.

Treatment of single brain metastasis with resection, intracavity carmustine polymer wafers, and radiation therapy is safe and provides excellent local control.

Purpose: To define the safety and efficacy of carmustine polymer wafers when added to a regimen of surgery and external beam radiotherapy for treatment of a single brain metastasis.

Experimental Design: Adult patients underwent craniotomy for a single brain metastasis, and carmustine polymer wafers were placed in the tumor resection cavity. Patients then received whole-brain radiotherapy and were followed for patterns of recurrence in the central nervous system, toxicity, and survival.

Heparin-binding EGF-like growth factor mediates oxyhemoglobin-induced suppression of voltage-dependent potassium channels in rabbit cerebral artery myocytes.

Oxyhemoglobin (OxyHb) can suppress voltage-dependent K(+) channel (K(V)) currents through protein tyrosine kinase activation, which may contribute to cerebral vasospasm following subarachnoid hemorrhage. Here we have tested the hypothesis that shedding of heparin-binding EGF-like growth factor (HB-EGF) and the resulting activation of the tyrosine kinase EGF receptor (EGFR) underlie OxyHb-induced K(V) channel suppression in the cerebral vasculature. With the use of the conventional whole cell patch-clamp technique, two EGFR ligands, EGF and HB-EGF, were found to mimic OxyHb-induced K(V) suppression in rabbit cerebral artery myocytes.

A modeling study of idiopathic intracranial hypertension: etiology and diagnosis.

Objective: To investigate the relationship between idiopathic intracranial hypertension (IIH) and transverse sinus stenosis through experiments performed on a validated mathematical model.

Methods: A mathematical model of intracranial pressure (ICP) dynamics has been extended to accommodate venous sinus compression through the introduction of a Starling-like resistor between the sagittal and transverse sinuses.

Results: In the absence of this type of resistor, the sinuses are rigid, and the model has only a unique, stable steady state with normal pressures.

Idiopathic intracranial hypertension and transverse sinus stenosis: a modelling study.

Idiopathic intracranial hypertension (IIH) is a syndrome of unknown etiology characterized by elevated intracranial pressure (ICP). Although a stenosis of the transverse sinus has been observed in many IIH patients, the role this feature plays in IIH is in dispute. In this paper, a lumped-parameter model is developed for the purpose of analytically investigating the elevated pressures associated with IIH and a collapsible transverse sinus.

Oxyhemoglobin-induced suppression of voltage-dependent K+ channels in cerebral arteries by enhanced tyrosine kinase activity.

Cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) has devastating consequences. Oxyhemoglobin (oxyhb) has been implicated in SAH-induced cerebral vasospasm as it causes cerebral artery constriction and increases tyrosine kinase activity. Voltage-dependent, Ca(2+)-selective and K(+)-selective ion channels play an important role in the regulation of cerebral artery diameter and represent potential targets of oxyhb.

Ca2+ source-dependent transcription of CRE-containing genes in vascular smooth muscle.

Altered Ca2+ handling has immediate physiological and long-term genomic effects on vascular smooth muscle function. Previously we showed that Ca2+ entry through voltage-dependent Ca2+ channels (VDCCs) or store-operated Ca2+ channels (SOCCs) results in phosphorylation of the Ca2+/cAMP response element (CRE)-binding protein in cerebral arteries. Here, oligonucleotide array analysis was used to determine gene transcription profiles resulting from these two Ca2+ entry pathways in human cerebrovascular smooth muscle cell cultures.

Modeling steady-state intracranial pressures in supine, head-down tilt and microgravity conditions.

Introduction: The effects of microgravity are often simulated by head-down tilt (HDT). While data exist for intracranial pressure (ICP) during short-term HDT, no corresponding data exist for long-term exposure to HDT or microgravity. A mathematical model was developed to predict these unknown long-term responses.

Nitric oxide and reactive oxygen species exert opposing effects on the stability of hypoxia-inducible factor-1alpha (HIF-1alpha) in explants of human pial arteries.

Hypoxia induces angiogenesis, partly through stabilization of hypoxia-inducible factor-1alpha (HIF-1alpha), leading to transcription of pro-angiogenic factors. Here we examined the regulation of HIF-1alpha by hypoxia and nitric oxide (NO) in explants of human cerebrovascular smooth muscle cells. Cells were treated with NO donors under normoxic or hypoxic (2% O2) conditions, followed by analysis of HIF-1alpha protein levels.

A whole-body mathematical model for intracranial pressure dynamics.

Most attempts to study intracranial pressure using lumped-parameter models have adopted the classical "Kellie-Monro Doctrine," which considers the intracranial space to be a closed system that is confined within the nearly-rigid skull, conserves mass, and has equal inflow and outflow. The present work revokes this Doctrine and develops a mathematical model for the dynamics of intracranial pressures, volumes, and flows that embeds the intracranial system in extensive whole-body physiology. The new model consistently introduces compartments representing the tissues and vasculature of the extradural portions of the body, including both the thoracic region and the lower extremities.