Journal of neurosurgery
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Journal of neurosurgery · Aug 1989
Case ReportsCranial burr hole for revascularization in moyamoya disease.
Currently, superficial temporal artery-middle cerebral artery (MCA) anastomosis, encephalomyosynangiosis (EMS), and encephalo-duro-arterio-synangiosis are used to treat moyamoya disease and are reported to effectively improve ischemic symptoms. All are methods of reversing the flow of blood from the external carotid artery system into the cortical branches of the MCA. As moyamoya disease advances, these operations alone will predictably not correct the deterioration in blood flow in the territory of the anterior cerebral artery. ⋯ In two cases a frontal burr hole was placed simultaneously with EMS, and in the others the frontal burr hole was made following EMS. The clinical symptoms improved after the frontal burr hole was made, and dynamic computerized tomography revealed improved circulation in the frontal regions. Together with conventional surgical therapy for juvenile cases of moyamoya disease, this operation is considered beneficial both to the circulation in the frontal region and for the protection of frontal brain function.
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By conventional criteria, an apneic patient's PaCO2 must be greater than 60 mm Hg before apnea can be attributed to brain death. The rate of a PaCO2 increase in the apneic patient traditionally has been thought to be in the range of 3 mm Hg/min. In order to assess the validity of these data and the validity of the "apnea test" for determination of brain death, the results of this test were reviewed in 20 patients. ⋯ These lengthy tests could have been avoided by utilizing a standardized apnea test with a baseline PaCO2 of 40 mm Hg or greater. The observation that a high baseline PaCO2 greatly augments the efficiency and safety of the test allows criteria that have previously been based on conjecture to be documented and applied clinically. A standardized apnea test, utilizing these principles, may satisfy many of the criticisms regarding brain-death testing that have been raised by neurologists, neurosurgeons, and transplant surgeons.
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To investigate the hemodynamics of intracranial circulatory arrest, the authors correlated the findings of noninvasive transcranial Doppler ultrasonography (TCD) with those of transfemoral four-vessel angiography in 65 patients following brain death and intracranial circulatory arrest due to severe intracranial hypertension. The three TCD stages of intracranial circulatory arrest, which have been described previously, corresponded with different levels of extracerebral angiographic cessation of flow. ⋯ The basal cerebral arteries remain patent in the early stages of intracranial circulatory arrest. Experimental evidence from the literature, together with the findings of the present investigation, points to the capillary bed as the initial site of the flow obstruction in progressing intracranial hypertension.