Journal of neurosurgery
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Arachnoid cysts are a frequent finding on intracranial imaging. The prevalence and natural history of these cysts in adults are not well defined. ⋯ Arachnoid cysts are a common incidental finding on intracranial imaging in all age groups. Although arachnoid cysts are symptomatic in a small number of patients, they are associated with a benign natural history for those presenting without symptoms.
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Journal of neurosurgery · Feb 2013
PlGF and sVEGFR-1 in chronic subdural hematoma: implications for hematoma development.
A considerable body of evidence indicates that inflammation and angiogenesis play a significant role in the development and progression of chronic subdural hematoma (CSDH). While various experimental and clinical studies have implicated placental growth factor (PlGF) in the processes that underpin pathological angiogenesis, no study has thus far investigated its expression in CSDH. The actions of PlGF and its related proangiogenic vascular endothelial growth factor (VEGF) are antagonized by a high-affinity soluble receptor, namely soluble VEGF receptor-1 (sVEGFR-1), and thus the ratio between sVEGFR-1 and angiogenic factors provides an index of angiogenic capacity. ⋯ Given previous evidence indicating a role for PlGF in promoting angiogenesis, inflammatory cell chemotaxis, and stimulation, as well as its ability to amplify VEGF-driven signaling under conditions favoring pathological angiogenesis, enhanced expression of PlGF in hematoma fluid suggests the involvement of this factor in the mechanisms of inflammation and angiogenesis in CSDH. Furthermore, a reduced ratio of sVEGFR-1 to PlGF in hematoma fluid is consistent with the proangiogenic capacity of CSDH. Future studies are warranted to clarify the precise role of PlGF and sVEGFR-1 in CSDH.
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Journal of neurosurgery · Feb 2013
Case ReportsTechnical nuances of temporal muscle dissection and reconstruction for the pterional keyhole craniotomy.
The supraorbital keyhole approach offers a limited access for aneurysms located at the middle cerebral artery (MCA) bifurcation with long M(1) segments or proximal M(2) aneurysms. Alternative minimally invasive routes centered on the pterion have been developed to address these aneurysms. Appropriate dissection and reconstruction of the temporal muscle are important for optimal exposure and best cosmetic results with the pterional keyhole craniotomy. ⋯ This dissection technique prevents damage to branches of the facial nerve and minimizes temporal muscle damage. Dividing the temporal muscle vertically and reflecting both parts anteriorly and posteriorly prevents suboptimal illumination and visualization under the microscope. Covering the bone flap and related hardware with a multilayer anatomical reconstruction optimizes cosmetic results.
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Journal of neurosurgery · Feb 2013
Case ReportsAntibacterial therapeutic drug monitoring in cerebrospinal fluid: difficulty in achieving adequate drug concentrations.
This report illustrates the difficulty in managing CNS infection in neurosurgical patients, the altered drug pharmacokinetics associated with critical illness, and the role that therapeutic drug monitoring (TDM) of CSF can play in assisting clinical decision making. The authors present a case of external ventricular drain-related ventriculitis in a critically ill patient who initially presented with a subarachnoid hemorrhage. They discuss the physiological changes found in such patients, in particular augmented renal clearance (demonstrated in this patient by a measured creatinine clearance of 375 ml/min/1.73 m(2)), noting the effect this had on drug pharmacokinetics and leading to dosing requirements 2-3 times those recommended in standard regimens. The authors consider the bacterial "kill" characteristics of 2 different antibacterial agents (meropenem and vancomycin) and describe the unique approach of using plasma and CSF TDM to achieve optimal drug exposure at the site of infection while limiting toxic side effects. ⋯ However, prior to any recommendations regarding empirical dose modification, more data are clearly needed, particularly with respect to the safety and efficacy of such an approach. In this respect, the authors would advocate further research using TDM in the management of CNS infection in this setting, in addition to work defining plasma and CSF concentrations associated with antibacterial efficacy and toxicity.
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Journal of neurosurgery · Feb 2013
Clinical TrialThe warning-sign hierarchy between quantitative subcortical motor mapping and continuous motor evoked potential monitoring during resection of supratentorial brain tumors.
Mapping and monitoring are believed to provide an early warning sign to determine when to stop tumor removal to avoid mechanical damage to the corticospinal tract (CST). The objective of this study was to systematically compare subcortical monopolar stimulation thresholds (1-20 mA) with direct cortical stimulation (DCS)-motor evoked potential (MEP) monitoring signal abnormalities and to correlate both with new postoperative motor deficits. The authors sought to define a mapping threshold and DCS-MEP monitoring signal changes indicating a minimal safe distance from the CST. ⋯ Mapping should primarily guide tumor resection adjacent to the CST. DCS-MEP is a useful predictor of deficits, but its value as a warning sign is limited because signal alterations were reversible in only approximately 60% of the present cases and irreversibility is a post hoc definition. The true safe mapping MT is lower than previously thought. The authors postulate a mapping MT of 1 mA or less where irreversible DCS-MEP changes and motor deficits regularly occur. Therefore, they recommend stopping tumor resection at an MT of 2 mA at the latest. The limited spatial and temporal coverage of contemporary mapping may increase error and may contribute to false, higher MTs.