Neurosurgery
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Comparative Study
Intraoperative magnetic resonance imaging-guided neurosurgery at 3-T.
Between 1997 and 2004, more than 700 neurosurgical procedures were performed in a 1.5-T magnetic resonance-guided therapy suite. During this period, the concept of high-field intraoperative magnetic resonance imaging (MRI) was validated, as was a new surgical guidance tool, the Navigus (Image-guided Neurologics, Melbourne, FL), and its methodology, prospective stereotaxy. Clinical protocols were refined to optimize surgical techniques. That implementation, the "Minnesota suite," has recently been revised, and a new suite with a 3-T MRI scanner has been developed. ⋯ An intraoperative magnetic resonance-guided neurosurgical theater has been developed with a 3-T MRI scanner. Intraoperative imaging is feasible at this field strength, and concerns regarding specific absorption rate can be allayed. Infection control procedures can be designed to permit neurosurgery within this environment. Despite the increase in magnetic field strength, safety can be maintained.
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Locked-in syndrome is a state of preserved consciousness in the setting of quadriplegia, anarthria, and usually also includes lateral gaze palsy. It is most commonly associated with upper brainstem infarction variably sparing the third cranial nerve nucleus. There are likely many etiologies that contribute to this clinical syndrome. These are incompletely understood, and the syndrome remains a rare but devastating complication that can occur after neurosurgical and neurovascular interventions. Advanced magnetic resonance imaging techniques such as perfusion and diffusion tensor imaging may help to elucidate the mechanism behind locked-in syndrome. To the authors' knowledge, there are no reports in the literature of perfusion and diffusion tensor findings in patients with this syndrome. A postprocedural case of locked-in syndrome is described with abnormalities on perfusion and diffusion tensor imaging in the absence of any changes in conventional magnetic resonance imaging. ⋯ Postprocedural angiography demonstrated patency of the bypass graft, and diffusion weighted imaging showed no evidence for acute brainstem infarction. Nevertheless, despite technically successful procedures and the absence of abnormalities on conventional magnetic resonance imaging, the patient developed quadriplegia and anarthria and remained in a locked-in state until he expired. Abnormalities were, however, seen on both perfusion and diffusion tensor imaging, where hypoperfusion, increased mean diffusivity, and decreased fractional anisotropy were observed in the ventral brainstem. The findings suggested a disruption of pontine white matter tracts. Advanced imaging techniques may allow us to image important microstructural changes that were previously not discernable and assist in the evaluation of patients with complex neurological sequelae such as locked-in syndrome.
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Comparative Study
Medial sphenoid wing meningiomas: clinical outcome and recurrence rate.
To provide clinical data concerning the visual outcome and recurrence rate of medial sphenoid wing meningiomas in consideration of two different subgroups of this tumor entity. ⋯ Group 1 meningiomas present a more favorable subgroup with fortunate visual outcome. In Group 2 tumors, visual improvement was less favorable and radical removal is limited because of cavernous sinus infiltration, with consequential higher recurrence rates. Patients harboring recurrent Group 2 tumors with deteriorating visual function profit from microsurgery because vision can be preserved on the same preoperative level in the majority.
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To describe a novel application of the Neuroform stent (Boston Scientific-Target, Fremont, CA) for the management of eight wide-necked aneurysms. ⋯ The Neuroform stent is a versatile device that can be used in a variety of ways to assist in the coiling of wide-necked aneurysms. The technique described here may be used for bifurcation aneurysms in lieu of using two stents in a Y configuration.
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Comparative Study
Endovascular treatment of unruptured intracranial aneurysms: occurrence of thromboembolic events.
The purpose of this study was to evaluate the frequency and causes of thromboembolic events associated with endovascular embolization of asymptomatic aneurysms. Correlations between radiological findings (aneurysm size, localization, embolization time, number of coils used, as well as patient age) were evaluated with the occurrence of thromboembolic events and clinical findings. ⋯ The high rate of thromboembolic events suggests that heparin is not sufficient to prevent ischemic lesions. An antiplatelet therapy, started before or during intervention, might diminish thrombus formation.