Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2006
The effect of intravenous fluid replacement on the response to mannitol in experimental cerebral edema: an analysis of intracranial pressure, serum osmolality, serum electrolytes, and brain water content.
Albino rabbits that had undergone a cryogenic insult over the left parieto-occipital cortex were analyzed for serum osmolality, serum electrolytes, brain water content, and intracranial pressure (ICP) following either a baseline infusion of intravenous (i.v.) fluid (45 mL total) for 3 hours or above-maintenance isotonic saline (73.5 +/- 12 mL or 90.5 +/- 1.5 mL) and mannitol therapy. The subgroups were compared amongst themselves and to sham-operated controls. Serum osmolality was elevated in the higher-dose mannitol subgroup compared with maintenance i.v. fluids subgroup (1 g/kg/h vs 1 g/kg/3 h; p < 0.05), accompanied by an insignificant reduction of serum sodium. ⋯ Reduction of ICP was not found in the lower mannitol dose group. We conclude that the ability of mannitol to reduce cerebral edema is related to the total amount of i.v. fluid replacement. This implies that the amount of i.v. crystalloid fluid that is administered to patients with cerebral edema and raised ICP requiring mannitol for control needs to be carefully monitored.
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Acta Neurochir. Suppl. · Jan 2006
Granulocyte colony-stimulating factor does not affect contusion size, brain edema or cerebrospinal fluid glutamate concentrations in rats following controlled cortical impact.
Granulocyte colony-stimulating factor (G-CSF) is an established treatment in the neutropenic host. Usage in head-injured patients at risk for infection may aggravate brain damage. In contrast, evidence of G-CSF neuroprotective effects has been reported in rodent models of focal cerebral ischemia. We investigated effects of G-CSF in acute focal traumatic brain injury (TBI) in rats. ⋯ A single injection of G-CSF did not influence cortical contusion volume, brain edema, or glutamate concentrations in CSF determined 24 hours following CCII in rats. G-CSF, administered 30 minutes following experimental TBI, failed to exert neuroprotective effects.
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Acta Neurochir. Suppl. · Jan 2006
Bolus tracer delivery measured by MRI confirms edema without blood-brain barrier permeability in diffuse traumatic brain injury.
Previous studies have shown that edema formation after diffuse traumatic brain injury (TBI) with secondary insult is cytotoxic and not vasogenic. This assumption is based on observations of reduced apparent diffusion coefficient (ADC) and lack of significant accumulation of intravascular tracer in brain tissue. However, ADC reduction does not exclude vasogenic edema, and intravascular tracer can only accumulate when it reaches the tissue and is not perfusion limited. This study aims to confirm tissue delivery of intravascular tracer and lack of BBB opening during a phase of rapid brain swelling after diffuse TBI. ⋯ Progressive cerebral edema formation after diffuse TBI occurred during ADC reduction and without continued BBB permeability. Tissue delivery of Gd-DTPA was confirmed, verifying that lack of tracer accumulation is due to an intact BBB and not to limited perfusion.
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1) Numerous of the so-called "unpredictable" post-operative complications are likely to be related to the lack of prevention or non-recognition of venous problems, especially damages to the dangerous venous structures, namely: the major dural sinuses, the deep cerebral veins and some of the dominant superficial veins like the vein of Labbé. 2) Tumors invading the major dural sinuses (superior sagittal sinus, torcular, transverse sinus)--especially meningiomas--leave the surgeon confronted with a dilemma: leave the fragment invading the sinus and have a higher risk of recurrence, or attempt at total removal with or without venous reconstruction and expose the patient to a potentially greater operative danger. Such situations have been encountered in 106 patients over the last 25 years. For decision-making, meningiomas were classified into six types according to the degree of sinus invasion. ⋯ Type V: this type can be recognized from type VI only by direct surgical exploration of the sinus lumen. Opposite wall to the tumor side is free of tumor, it is possible to reconstruct the two resected walls with patch. Type VI: removal of involved portion of sinus and restoration with venous bypass. 3) As 20% of the patients presenting with manifestations of intracranial hypertension due to occlusion of posterior third of the superior sagittal sinus, torcular, predominant lateral sinus or internal jugular vein(s) develop severe intracranial hypertension, venous revascularisation by sino-jugular bypass--implanted proximally to the occlusion and directed to the jugular venous system (external or internal jugular vein)--can be a solution.
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In neurorehabilitation, transcranial magnetic stimulation (TMS) offers information regarding prognosis and pathophysiology and could also be useful for therapeutic purposes. Numerous studies have indicated that, after stroke, the absence of motor evoked potentials is associated with a poor motor recovery. In contrast, MEPs obtained in the paretic muscle with low stimulus intensities suggest a good restitution of motor function. ⋯ Stroke patients participating in a Constraint-induced movement therapy show an enlargement of the motor output area in the affected hemisphere after therapy. This enhancement of motor excitability is associated with an improvement of motor function. Some evidence is emerging that the application of low frequency repetitive TMS over the non-lesioned hemisphere improves neglect phenomena by down-regulation of the excitability of the non-lesioned hemisphere.