Neurosurgery
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To analyze the effect of stereotactic radiosurgery on the hemorrhage rate of arteriovenous malformations (AVMs), we reviewed the clinical and angiographic characteristics of 315 patients with AVMs before and after radiosurgery. One hundred ninety-six patients sustained 263 bleeds in 10,939 patient-years before radiosurgery, for an annual nonfatal hemorrhage rate of 2.4%. Clinical follow-up after radiosurgery was available in 312 patients (mean, 47 +/- 20 mo); follow-up > or = 24 months was obtained in 295 patients (94%). ⋯ Stereotactic radiosurgery was not associated with a significant change in the hemorrhage rate of AVMs during the latency interval before obliteration. No protective benefit was conferred on patients who had incomplete nidus obliteration in early (< 60 mo) follow-up after radiosurgery. AVM patients with unsecured proximal aneurysms should have aneurysms obliterated either before radiosurgery or at the time of surgical resection of their AVMs.
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Some neurosurgeons state that intra-axial tumors may be resected with a low risk of neurological deficit if the tumor removal stays within the confines of the grossly abnormal tissue. This is thought to be so even when the lesion is presumably located in a functional area, providing that the adjacent normal-appearing cortex and subcortical white matter are not disturbed. This retrospective analysis presents evidence that this view is not always correct, because functioning motor, sensory, or language tissue can be located within a grossly obvious tumor or the surrounding infiltrated brain. ⋯ Nineteen patients had new or worsened neurological deficits immediately after the operation, but after 3 months, only 6 continued to show new deficits whereas 18 showed no deficits and 2 improved. These results demonstrate that regardless of the degree of tumor infiltration, swelling, apparent necrosis, and gross distortion by the mass, functional cortex and subcortical white matter may be located within the tumor or the adjacent infiltrated brain. Therefore, to safely maximize glioma resection in these functional areas, intraoperative stimulation mapping may be used to identify functional cortical or subcortical tissue within, as well as adjacent to, the tumor, thus avoiding permanent injury.
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Comparative Study
The significance of artificial cerebrospinal fluid as perfusate and endoneurosurgery.
To compare the benefits of physiological saline solution and artificial cerebrospinal fluid (CSF) as perfusates, we investigated 12 patients with presumed symptomatic aqueductal stenosis by clinical course and CSF analysis. In all patients, endoneurosurgical third ventriculostomy and cine magnetic resonance imaging confirmed the patency of ventriculostomy. ⋯ In contrast, the artificial CSF reduced these conditions to a minimum. Artificial CSF used as a physiological perfusate during endoneurosurgery can suppress host reactions within the CSF pathway and is also available for routine neurosurgical procedures.
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Histoanatomically invading astrocytoma cells appear to migrate along distinct structures within the brain. Astrocytoma invasion may occur along extracellular matrix (ECM) protein-containing structures, such as blood vessels, but most frequently occurs along tracts of myelinated fibers. This behavior most likely is a consequence of the use of constitutive extracellular ligands expressed along the pathways of preferred dissemination. ⋯ For both glioblastoma primary cell preparations, myelin and merosin were the most permissive substrates for attachment and migration. Other ECM proteins (collagen type IV, fibronectin, and vitronectin) were moderate or nonpermissive substrates. Our findings indicated that astrocytoma cells may be able to use oligodendrocyte membrane-associated ligands as well as ECM proteins of the basement membranes for invasion of normal brain.
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We evaluated the role of stereotactic radiosurgery (SRS) in 25 children with surgically incurable brain tumors of glial origin. Histological diagnoses were obtained at the time of craniotomy and attempted removal (n = 20) or by stereotactic biopsy (n = 5). Thirteen children had tumors with benign histological characteristics (pilocytic and low-grade astrocytomas), whereas 12 children had tumors with malignant characteristic (malignant astrocytomas and ependymomas). ⋯ There was no relationship between tumor volume and local control after radiosurgery. Radiosurgery alone is a safe and effective treatment modality for unresectable benign gliomas of childhood. Radiosurgery may have a role in the adjuvant management of unresectable malignant glial neoplasms of childhood if other therapies (irradiation or chemotherapy) are available.