Neurological research
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Neurological research · Apr 2002
Adequate cerebral perfusion pressure during rewarming to prevent ischemic deterioration after therapeutic hypothermia.
Ischemic deterioration during rewarming is one of the most notable clinical complications after successful therapeutic cerebral hypothermia, but the mechanism is not completely understood. Hypothermia may cause vasoconstriction and relative ischemia, especially with insufficient cerebral perfusion pressure (CPP). Various parameters were evaluated to determine the critical CPP threshold to avoid ischemia during rewarming. ⋯ Extracellular glutamate significantly increased during the rewarming period only in the CPP= 40 mmHg group. CPP less than 60 mmHg during rewarming causes secondary ischemic insult, which might indicate continuation of cerebral vasoconstriction in hypothermia. CPP higher than 90 mmHg is required to avoid the potential risk of relative ischemia after hypothermia.
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Neurological research · Apr 2002
The anatomy of the circle of Willis as a predictive factor for intra-operative cerebral ischemia (shunt need) during carotid endarterectomy.
The collateral flow to the cerebral hemisphere after carotid cross clamping during carotid endarterectomy is mainly through the circle of Willis, and the circle is incomplete in the majority of cases. A correlation between the status of the circle of Willis and the necessity of shunting was evaluated in 67 carotid endarterectomies with pre-operative four-vessel cerebral angiogram. All carotid endarterectomies were performed with selective shunting, based on the change of consciousness and motor function after carotid test clamping under regional anesthesia. ⋯ Twelve patients had neither anterior nor posterior communicating artery, and 10 (83.3%) showed signs of cerebral ischemia necessitating shunting. Mandatory shunt was significantly higher in patients with absence of collaterals (p = 0.00). The rate of intraoperative cerebral ischemia was significantly higher in patients with poor collateral circulation defined by the anatomy of the circle of Willis.
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Neurological research · Apr 2002
ACoA angle measured by computed tomographic angiography and its relevance in the pterional approach for ACoA aneurysms.
The purpose of this study was to analyze the spatial disposition of the anterior communicating artery (ACoA) complex and the orientation of the ACoA plane by computed tomographic angiography with three-dimensional reconstruction (3D-CTA) and to evaluate the relevance of the orientation of the ACoA plane in the planification of the surgical approach to the ACoA complex aneurysms. The dominance of the right or left A1 segment of the anterior cerebral artery, the position of the A1-A2 junction in relation to the transverse plane and the angulation of plane of the ACoA traject were studied using 3D-CTA in 30 patients with subarachnoid hemorrhage. Twelve patients harbored an aneurysm on the ACoA complex and the most relevant anatomic characteristics of these lesions were recorded. ⋯ The angulation of the ACoA plane, in combination with the orientation of the aneurysm, must be included among the criteria for the selection of the route of the surgical approach. This information is given by the 3D-CTA. All of these data allows a pre-operative simulation of the surgical approach to the lesion for a safer clipping of the neck of the aneurysm.