Neurosurgery
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Subdural arrays of grid and strip electrodes are frequently used in epilepsy patients to localize the seizure focus and determine the location of critical brain functions via stimulation mapping. Postoperatively, the majority of patients with implanted subdural electrodes develop subacute extra-axial collections (EACs). Although conservative management is appropriate in most of these cases, occasionally patients manifest neurological symptoms that may necessitate reoperation for collection evacuation. Currently, there is little information available regarding the range of EAC size and the potential correlation between EAC size and symptom development. To facilitate treatment decision-making in postoperative subdural electrode patients, we reviewed and compared the computed tomographic (CT) features of postelectrode placement EACs in asymptomatic and symptomatic patients. ⋯ The conventional methods of midline shift and maximal thickness for assessing EAC size did not adequately differentiate symptomatic and asymptomatic subdural electrode patients with EACs. Although total volume calculation using digital planimetric analysis demonstrated a statistically significant difference, we found no clear threshold volume that correlated with clinical course. Therefore, the appearance of EACs on CT scans is of limited use in predicting the development of symptoms and possible postoperative complications after subdural grid placement. Clinical judgment must guide management and determine the potential need for reoperation.
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Previously, we demonstrated that a recombinant Listeria monocytogenes (rLM) vector encoding the melanoma-associated antigen, tyrosinase related protein (TRP)-2, could successfully treat subcutaneous B16 melanomas. The purpose of the present study was twofold: 1) to test whether this rLM-nucleoprotein (NP)/TRP-2 could generate antitumor immunity to a B16 tumor challenge in the immunologically privileged central nervous system (CNS) and 2) to develop a noninvasive imaging modality to monitor tumor progression in the brain after immunotherapy. ⋯ The ability to treat tumors arising within the CNS is difficult because of the nature of the anatomic confines of the brain and a microenvironment that may not promote immune responsiveness. These studies describe an in vivo bioluminescent imaging system to monitor CNS tumor growth in mice, which we successfully used to document decreased intracranial tumor progression and size after vaccination with rLM-NP/TRP-2. The results suggest that metastatic tumors in the CNS can be targeted immunotherapeutically without overt autoimmune toxicity.
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Randomized Controlled Trial
High dose magnesium infusions are not associated with increased pressor requirements after carotid endarterectomy.
Although magnesium provides cerebral protection in animal stroke models, magnesium therapy has significant side effects in humans. Therefore, we sought to examine the incidence of alpha-agonist treated hypotension in our ongoing, prospective, randomized, double-blind, placebo-controlled Phase I/IIa dose escalation study of magnesium therapy in patients undergoing carotid endarterectomy. ⋯ There were no significant differences detected in the 1) percentage of patients requiring pressor support, 2) the duration of postoperative pressor support, or 3) the amount of phenylephrine support needed between controls and magnesium treated patients. The percentage of patients requiring pressure support depended on the minimum systolic blood pressure ordered after surgery.
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The motor thalamus is an important target for the treatment of tremor. It receives afferents from the cerebellum, globus pallidus internus, and substantia nigra and projects mainly to the motor cortex, premotor cortex, and supplementary motor area. Various nomenclatures have been proposed to subdivide the motor thalamus, none of which are universally accepted. ⋯ Modern neurophysiological techniques have allowed the recording of the activity of thalamic neurons in patients with different clinical conditions. This has provided a better understanding of the functions of the motor thalamus in humans. The aim of the present article is to briefly review the major anatomic and physiological aspects of the motor thalamus as well as the electrophysiological findings described in humans undergoing surgical procedures.