Journal of neurosurgery
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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 · 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
Psychosocial functioning and quality of life in patients with primary brain tumors.
Perceived quality of life (QOL) was evaluated in a group of 50 patients with primary brain tumors. Participants completed two QOL measures and a demographic profile. Age was found not to be an important factor in differentiating QOL in these patients. ⋯ This study is one of the first to evaluate the multidimensional aspects of QOL in patients with primary brain tumors, an understudied group. A prospective study of QOL in this group, already underway at the authors' institution, is needed to evaluate comprehensively the effect of different treatments and interventions on the QOL functioning of primary brain tumor patients. Additionally, this study shows that the choice of QOL instruments is very important and needs to be driven by the research question.
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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.
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Journal of neurosurgery · Dec 1995
Cannulated screws for odontoid screw fixation and atlantoaxial transarticular screw fixation. Technical note.
Cannulated screw systems use thin Kirschner wires (K-wires) that have been drilled into the bone to direct screw trajectories accurately into small bone fragments. Use of the K-wires avoids overdrilling the pilot holes and allows fixation of adjacent bone fragments during screw insertion. Hollow tools and hollow screws are inserted into the bone over the K-wires. ⋯ A unique cannulated screw tool system was developed specifically for upper cervical fixation to allow percutaneous drilling using long tunneling devices, tissue sheaths, drill guides, and long K-wires. These tools allow delivery of cannulated fracture-fixation screws at a low angle to the spine through long soft-tissue trajectories. Cannulated screws have significant advantages compared to noncannulated screws for fixation of the unstable cervical spine.