Neurosurgery
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Since its first application in 1967, the methodology and technology of spinal cord stimulation for the management of chronic, intractable pain have evolved continuously. Despite these developments and improved knowledge of the effects of spinal anatomy and epidural contact configuration on paresthesia coverage, the clinical results of spinal cord stimulation-particularly the long-term effects-are still unsatisfactory in many patients. This dissatisfaction has come primarily from the failure of single-electrode configurations to provide consistent paresthesia coverage of the entire painful area. ⋯ To target parts of the latter, different methods have been developed and tested using either two-dimensional contact configurations or electronic field steering. These developments hold promise for improving long-term outcomes as well as increasing the number of pain conditions that can be treated with neuromodulation therapy. In this review, the history, theoretical basis, and evolution of these methodologies, as well as the ways in which they represent new trends in neuromodulation, are discussed.
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Abnormal serum sodium levels (hyponatremia and hypernatremia) are frequently observed during the acute period after aneurysmal subarachnoid hemorrhage (SAH) and may worsen cerebral edema and mass effect. We performed this study to determine the prognostic significance of serum sodium concentration abnormalities. ⋯ Hyponatremia seems to be more common than hypernatremia after SAH. However, hypernatremia after SAH is independently associated with poor outcomes, and this association is independent of previously identified outcome predictors, including age and admission Glasgow Coma Scale scores. Further studies are needed to define the underlying mechanism of this association.
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To evaluate long-term clinical outcomes after severe, acute, pediatric brain trauma, in relation to cerebral extraction of oxygen (CEO(2)) and intracranial pressure abnormalities treated with a protocol to simultaneously normalize both parameters. ⋯ In severe, acute, non-missile pediatric brain trauma, phasic physiological patterns demonstrated an association between the development of intracranial hypertension and relative cerebral hyperperfusion (decreased global CEO(2)), especially after postinjury Day 1. Unfavorable clinical outcomes were significantly related to more pronounced intracranial hypertension and more profound concomitant decreases in CEO(2), indicating hyperoxic uncoupling between global cerebral consumption of oxygen and cerebral blood flow.
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To determine the value of delayed surgical resection in patients with central nervous system germ cell tumors who exhibit less than complete radiographic response despite declining serum and cerebrospinal fluid (CSF) tumor markers after initial chemotherapy. ⋯ Delayed surgical resection should be considered in patients with central nervous system germ cell tumors who have residual radiographic abnormalities and normalized tumor markers, because these lesions are likely to be teratoma or necrosis/scar tissue. However, second-look surgery should be avoided in patients whose tumor markers have not normalized completely.
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The goals of this investigation were to perform a detailed analysis of petroclival microanatomic features, to investigate the course of the abducens nerve in the petroclival region, and to identify potential causes of injury to neurovascular structures when anterior transpetrosal or transvenous endovascular approaches are used to treat pathological lesions in the petroclival region. ⋯ The petroclival part of the abducens nerve was protected in a dural sleeve accompanied by the arachnoid membrane. Therefore, the risk of abducens nerve injury during petrous apex resection via the anterior transpetrosal approach, with the use of the transvenous route through the inferior petrosal sinus to the cavernous sinus, should be lower than expected. The presence of two anatomic variations in the course of the abducens nerve, in addition to findings regarding nerve angulation and tethering points, may explain the relationships between adjacent structures and the susceptibility to nerve injury with either surgical or endovascular approaches. Venous anatomic variations may account for previously reported cases of subarachnoid hemorrhage with the endovascular approach.