Journal of neurosurgery
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The mechanism by which intracerebral hemorrhage leads to the formation of brain edema is unknown. This study assesses the components of blood to determine if any are toxic to surrounding brain. Various solutions were infused stereotactically into the right basal ganglia of rats. ⋯ On the other hand, activation of the coagulation cascade by adding prothrombinase to plasma did produce brain edema. The edema response to whole blood could be prevented by adding a specific thrombin inhibitor, hirudin, to the injected blood. This study indicates that thrombin plays an important role in edema formation from an intracerebral blood clot.
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Journal of neurosurgery · Jan 1996
Characterization of edema by diffusion-weighted imaging in experimental traumatic brain injury.
The objective of this study was to use diffusion-weighted magnetic resonance imaging (DWI) to help detect the type of edema that develops after experimental trauma and trauma coupled with hypotension and hypoxia (THH). Reduction in the apparent diffusion coefficients (ADCs) is thought to represent cytotoxic edema. In a preliminary series of experiments, the infusion edema model and middle cerebral artery occlusion models were used to confirm the direction of ADC change in response to purely extracellular and cytotoxic edema, respectively. ⋯ In the trauma alone group, the rise in ICP reached a maximum value (28 +/- 3 mm Hg) at 30 minutes with a significant and sustained increase in CBF despite a gradual decrease in CPP. The ADCs in this group were not significantly reduced. The data lead the authors to suggest that the rise in ICP following severe trauma coupled with secondary insult in this model is predominately caused by cytotoxic edema and that ischemia plays a major role in the development of brain edema after head injury.
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Journal of neurosurgery · Jan 1996
Relationship between transcranial Doppler-determined pulsatility index and cerebrovascular resistance: an experimental study.
Clinical studies with transcranial Doppler suggest that the pulsatility of the flow velocity (FV) waveform increases when the distal cerebrovascular resistance (CVR) increases. To clarify this relationship, the authors studied animal models in which the resistance may be decreased in a controlled manner by an increase in arterial CO2 tension, or by a decrease in cerebral perfusion pressure (CPP) in autoregulating animals. Twelve New Zealand white rabbits were anesthetized, paralyzed, and ventilated. ⋯ During the hypercapnic challenge the correlation between the cortical resistance and Doppler flow pulsatility was positive (r = 0.77, p<0.001). In all three groups in which cerebral perfusion pressure was reduced a negative correlation between pulsatility index and cerebrovascular resistance was found (r = -0.84, p<0.001). The authors conclude that PI cannot be interpreted simply as an index of CVR in all circumstances.
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Journal of neurosurgery · Dec 1995
Brain edema and neurological status with rapid infusion of lactated Ringer's or 5% dextrose solution following head trauma.
Rapid infusion of 0.25 ml/g of 0.9% saline over 30 minutes has been shown to have no effect on electrolyte balance, neurological severity score (NSS), or brain edema, following closed head trauma (CHT). Rapid infusion of the same volume of 5% dextrose solution decreased blood sodium concentration, increased edema, and decreased NSS following CHT. In the present study the authors examined the effect of rapid infusion (30 minutes) of smaller volumes of 5% dextrose (0.08 ml/g and 0.16 ml/g) and of 0.25 ml/g lactated Ringer's solution on blood electrolyte concentrations, plasma osmolality, brain edema, and NSS. ⋯ None of the groups treated with 0.16 ml/g 5% dextrose solution survived 24 hours. Although blood glucose concentration increased to 1126 +/- 102 g% (mean +/- standard deviation) and 1568 +/- 283 g% and blood sodium concentration decreased to 110.4 +/- 4.6 mEq/L and 92.0 +/- 5.2 mEq/L in the groups treated with 0.08 ml/g and 0.16 ml/g of 5% dextrose solution, respectively, plasma osmolality was normal and no significant difference could be found between the brain tissue specific gravity of animals in the nontreated and 5% dextrose treatment groups. It is concluded that in the CHT model used in this study, the large volume of lactated Ringer's solution did not affect blood electrolyte concentration, neurological outcome, or formation of brain edema, whereas smaller volumes of 5% dextrose solution increased blood glucose and decreased blood sodium concentrations, did not affect plasma osmolality, and had a deleterious effect on neurological outcome.
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Journal of neurosurgery · Dec 1995
Surgical approaches for the correction of unstable thoracolumbar burst fractures: a retrospective analysis of treatment outcomes.
The authors retrospectively studied 49 nonparaplegic patients who sustained acute unstable thoracolumbar burst fractures. All patients underwent surgical treatment and were followed for an average of 27 months. All but one patient achieved solid radiographic fusion. ⋯ There were no significant intergroup differences when considering postoperative kyphotic correction, neurological function, pain assessment, or the ability to return to work. Posterior surgery was found to be as effective as anterior or anterior-posterior surgery when treating unstable thoracolumbar burst fractures. Posterior surgery, however, takes the least time, causes the least blood loss, and is the least expensive of the three procedures.