Acta neurochirurgica
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Acta neurochirurgica · Jan 1999
Case ReportsRuptured aneurysm at the trunk of the accessory middle cerebral artery.
We present a 32-year-old woman with intracranial haemorrhage due to rupture of a saccular aneurysm arising from the trunk of an accessory middle cerebral artery. This is the first report of an aneurysm arising distally to the anomalous vessel's origin from the A1 segment of the anterior cerebral artery.
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Acta neurochirurgica · Jan 1999
Clinical TrialDissection from fundus to neck for ruptured anterior and middle cerebral artery aneurysms at the acute surgery.
It is generally believed that a ruptured aneurysm should be dissected from its neck to its fundus or that only the neck should be dissected. This study was conducted to clarify whether, during the acute stage, intra-operative bleeding occurs at the same site as the initial rupture point when aneurysms are dissected completely without clipping. The subjects were 170 patients with ruptured anterior or middle cerebral artery aneurysms who were surgically treated by day 7. ⋯ Intra-operative aneurysmal rupture occurred during dissection of the aneurysm itself in 8 patients, during dissection of the artery adhering to the aneurysm in 5 and during clip application in 3. In all the patients whose aneurysms ruptured during aneurysmal dissection, the rupture was caused by injury to the aneurysm and was not directly related to complete exposure of the aneurysm. Intra-operative bleeding did not occur at the same site as the initial rupture point even when the entire aneurysmal complex was dissected from the fundus to the neck without clipping.
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Acta neurochirurgica · Jan 1999
Monitoring of intracranial compliance: correction for a change in body position.
The objectives of our study were 1. to investigate whether the intracranial compliance changes with body position; 2. to test if the pressure-volume index (PVI) calculation is affected by different body positions; 3. to define the optimal parameter to correct PVI for changes in body position and 4. to investigate the physiological meaning of the constant term (P0) in the model of the intracranial volume-pressure relationship. Thirteen patients were included in this study. All patients were subjected to 2 to 3 different body positions. ⋯ Using the constant term P0 to correct the PVI we found no changes between the different body positions. Our results suggest that during the variation in body position there is no change in intracranial compliance but a change in hydrostatic offset pressure which causes a shifting of the volume-pressure curve along the pressure axis without its shape being affected. PVI measurements should either be performed only with the patient in the 0 degree recumbent position or that the PVI calculation should be corrected for the hydrostatic difference between the level of the ICP transducer and the hydrostatic indifference point of the craniospinal system close to the third thoracic vertebra.
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Acta neurochirurgica · Jan 1999
Assessment of critical closing pressure in the cerebral circulation as a measure of cerebrovascular tone.
Critical closing pressure (CCP) calculated from the blood flow velocity (FV) and arterial blood pressure (ABP) waveforms has been previously reported to be useful in the assessment of the dynamics of cerebral circulation. We investigated the relationship between CCP and intracranial pressure (ICP) and cerebrovascular tone in a model of intracranial hypertension in 22 anaesthetised New Zealand White rabbits during manipulations of arterial CO2, ABP and vasodilatation caused by hypoxia. Recordings were made of FV in the basilar artery, ABP and ICP during subarachnoid infusion of saline. ⋯ Generally, CCP decreased significantly (p<0.05) with hypercarbia, arterial hypotension and after and post-hypoxia and the difference: CCP-ICP decreased consistently after each vasodilatatory manoeuvre studied. Our data confirmed the linear relationship between CCP and ICP, and between the difference: CCP-ICP and cerebrovascular tone. However, because the magnitude of increase in ICP was not correlated to magnitude of change in CCP, CCP cannot be use for detection of increasing ICP quantitatively.
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This study tested the hypothesis that colloidal blood volume expansion could improve the cerebral circulation during high intracranial pressure. We studied cerebrovascular haemodynamic variables during high intracranial pressure with and without colloidal blood volume expansion in 12 pigs, whereas five pigs served as controls with intracranial pressure increase twice without colloidal blood volume expansion. Cerebral blood flow was measured with ultrasonic flowmetry on the internal carotid artery, and cerebral microcirculation with laser Doppler flowmetry. ⋯ Cerebral micro-circulation tended to increase, but this was not statistically significant (P = 0.07). Augmentation of the intravascular blood volume during high intracranial pressure increased the arterial inflow to the brain and possibly the cerebral microcirculation by increasing the cerebral perfusion pressure. Our results tend to support that the effect of colloidal blood volume expansion is beneficial for the cerebral circulation during high intracranial pressure.