Journal of neurosurgery
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Journal of neurosurgery · Jun 1998
Comparative StudyCombined supra/infratentorial-transsinus approach to large pineal region tumors.
The authors sought to confirm that the combined supra/infratentorial-transsinus approach offers a safer means of resecting large pineal region tumors than other approaches currently being used. The aforementioned method provides a wider exposure of the pineal region with less brain retraction than the infratentorial-supracerebellar or the occipital-transtentorial approach alone and is applicable to some large and giant tumors of this area. This combined approach was used in six patients to remove large pineal region tumors including four tentorial meningiomas, one pineocytoma, and one epidermoid cyst. ⋯ The combined supra/infratentorial-transsinus approach is preferred for the resection of certain large pineal region tumors.
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Journal of neurosurgery · Jun 1998
Comparative StudyEarly metabolic alterations in edematous perihematomal brain regions following experimental intracerebral hemorrhage.
The authors previously demonstrated, in a large-animal intracerebral hemorrhage (ICH) model, that markedly edematous ("translucent") white matter regions (> 10% increases in water contents) containing high levels of clot-derived plasma proteins rapidly develop adjacent to hematomas. The goal of the present study was to determine the concentrations of high-energy phosphate, carbohydrate substrate, and lactate in these and other perihematomal white and gray matter regions during the early hours following experimental ICH. ⋯ These results, which demonstrate normal to increased high-energy phosphate and carbohydrate substrate concentrations in edematous perihematomal regions during the early hours following ICH, are qualitatively similar to findings in other brain injury models in which a reduction in metabolic rate develops. Because an energy deficit is not present, lactate accumulation in edematous white matter is not caused by stimulated anaerobic glycolysis. Instead, because glutamate concentrations in the blood entering the brain's extracellular space during ICH are several-fold higher than normal levels, the authors speculate, on the basis of work reported by Pellerin and Magistretti, that glutamate uptake by astrocytes leads to enhanced aerobic glycolysis and lactate is generated at a rate that exceeds utilization.
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Journal of neurosurgery · Jun 1998
Comparative StudyAntivasospastic and brain-protective effects of a hydroxyl radical scavenger (AVS) after experimental subarachnoid hemorrhage.
The radical scavenger (+/-)-N,N'-propylenedinicotinamide (AVS) was shown recently to ameliorate delayed neurological deficits resulting from ischemia in patients who have had an aneurysmal subarachnoid hemorrhage (SAH). The aim of this study was to evaluate the effect of AVS administration after experimental SAH on 1) behavioral deficits; 2) angiographically confirmed basilar artery (BA) spasm; and 3) blood-brain barrier (BBB) permeability changes. ⋯ These results demonstrate useful antivasospastic and brain-protective actions of AVS after induction of experimental SAH and provide support for observations of beneficial effects of AVS made in the clinical setting.
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Journal of neurosurgery · May 1998
Comparative StudyProton magnetic resonance spectroscopy for detection of axonal injury in the splenium of the corpus callosum of brain-injured patients.
This study was conducted to determine whether proton magnetic resonance spectroscopy (MRS) is a sensitive method for detecting diffuse axonal injury, which is a primary sequela of traumatic brain injury (TBI). Diffuse axonal injury is characterized by selective damage to white matter tracts that is caused in part by the severe inertial strain created by rotational acceleration and deceleration, which is often associated with motor vehicle accidents. This axonal injury is typically difficult to detect by using conventional imaging techniques because it is microscopic in nature. The splenium was selected because it is a site vulnerable to shearing forces that produce diffuse axonal injury. ⋯ A majority of mildly brain injured patients, as well as those more severely injured, showed diminished NAA/creatine (Cr) levels in the splenium compared with normal control volunteers. The patients displaying lowered NAA/Cr in the splenium were also likely to exhibit lowered NAA/Cr in lobar white matter. Also, the levels of NAA/Cr in the splenium of normal volunteers were higher compared with those found in lobar white matter. Decreases in NAA/Cr levels in the splenium may be a marker for diffuse injury. A proton MRS examination may be particularly useful in evaluating mildly injured patients with unexplained neurological and cognitive deficits. It is concluded that MRS is a sensitive tool in detecting axonal injury.
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Journal of neurosurgery · May 1998
Comparative StudyCerebral perfusion pressure in head-injured patients: a noninvasive assessment using transcranial Doppler ultrasonography.
The authors studied the reliability of a new method for noninvasive assessment of cerebral perfusion pressure (CPP) in head-injured patients in which mean arterial blood pressure (ABP) and transcranial Doppler middle cerebral artery mean and diastolic flow velocities are measured. ⋯ Noninvasive estimation of CPP by using transcranial Doppler ultrasonography may be of value in situations in which monitoring relative changes in CPP is required without invasive measurement of intracranial pressure.