Journal of neurosurgery
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Journal of neurosurgery · Apr 2011
Sexual intercourse and cerebral aneurysmal rupture: potential mechanisms and precipitants.
Aneurysmal subarachnoid hemorrhage (SAH) is a significant cause of death in young and middle-aged individuals and causes tremendous morbidity in affected patients. Despite the identification of various risk factors, the series of events leading to the formation, growth, and rupture of intracranial aneurysms is poorly understood. Cerebral aneurysm rupture has been associated with sexual intercourse and other forms of physical exercise. ⋯ The authors' analysis is based on the original data collected by Masters and Johnson. To the authors' knowledge, this is the first review to address the link between sexual intercourse and intracranial aneurysmal rupture. While actual measurements of the physiological variables relevant to SAH were not performed in this article, the authors make reasonable assumptions based on the available data to help elucidate the mechanism of sexually induced aneurysmal rupture.
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Journal of neurosurgery · Apr 2011
Sphenopalatine ganglion stimulation for vasospasm after experimental subarachnoid hemorrhage.
Sphenopalatine ganglion stimulation activates perivascular vasodilatory nerves in the ipsilateral anterior circle of Willis. This experiment tested whether stimulation of the ganglion could reverse vasospasm and improve cerebral perfusion after subarachnoid hemorrhage (SAH) in monkeys. ⋯ Sphenopalatine ganglion stimulation decreased vasospasm and increased CBF after SAH in monkeys. This was associated with opening of the blood-brain barrier.
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Journal of neurosurgery · Apr 2011
Tamoxifen as an effective neuroprotectant in an endovascular canine model of stroke.
Tamoxifen has been shown to be a potent neuroprotectant against stroke in rodents. Because other neuroprotectant medications have failed in human trials, a study of tamoxifen in a large-animal model was necessary to further assess the drug's effectiveness. For this study, the authors developed an endovascular model of anterior circulation infarction in canines to mimic the human clinical condition. They assessed the following hypotheses: 1) that they will be able to consistently produce an internal carotid artery (ICA) terminus infarction and 2) that tamoxifen is an effective neuroprotectant against stroke in canines. ⋯ Using this endovascular model of stroke, the authors were able to consistently produce an infarction in the canines that was similar in scope to a carotid terminus occlusion in humans. Also, angiography could predict subsequent clinical course and infarct size. Tamoxifen was effective at significantly improving the canine neurological deficits and reducing the size of the stroke. This study took the first step in demonstrating the effectiveness of a promising human neuroprotectant in a large animal.
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Journal of neurosurgery · Apr 2011
Anatomical triangles defining surgical routes to posterior inferior cerebellar artery aneurysms.
Surgical routes to posterior inferior cerebellar artery (PICA) aneurysms are opened between the vagus (cranial nerve [CN] X), accessory (CN XI), and hypoglossal (CN XII) nerves for safe clipping, but these routes have not been systematically defined. The authors describe 3 anatomical triangles and their relationships with PICA aneurysms, routes for surgical clipping, outcomes, and angiographically demonstrated anatomy. ⋯ The anatomical triangles and zones clarify the borders of operative corridors to PICA aneurysms and define the depth of dissection through the CNs. Deep dissection to aneurysms in the anterior medullary zone traverses CNs X, XI, and XII, whereas shallow dissection to aneurysms in the lateral medullary zone traverses CNs X and XI. Posterior inferior cerebellar artery aneurysms outside the vagoaccessory triangle are frequently distal and superficial to the lower CNs, and associated surgical morbidity is minimal. Angiography may preoperatively localize a PICA aneurysm's triangular anatomy based on the distal PICA origin or distal aneurysm location.
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Journal of neurosurgery · Apr 2011
Optimal cerebrospinal fluid magnesium ion concentration for vasodilatory effect and duration after intracisternal injection of magnesium sulfate solution in a canine subarachnoid hemorrhage model.
The optimal CSF Mg(++) concentration for vasodilation of spastic cerebral arteries after subarachnoid hemorrhage (SAH) and its duration are unknown. The temporal profile of the vasodilatory effect and optimal CSF Mg(++) concentration after the intracisternal injection of MgSO(4) solution were investigated in an SAH model in canines. ⋯ The reversible effect of an intracisternal injection of MgSO(4) solution on the spastic artery requires CSF Mg(++) concentrations > 3 mEq/L. The vasodilatory effect continues for 3-6 hours after injection. These results suggest that the continuous infusion or intermittent intracisternal injection of MgSO(4) is needed to maintain the optimal CSF Mg(++) concentration and constantly ameliorate cerebral vasospasm.