Neurosurgery
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The aim of the present study is to monitor the extracellular gamma-aminobutyric acid (GABA) levels in the lumbar dorsal horn of allodynic rats, which respond to spinal cord stimulation (SCS) with a normalization of the tactile withdrawal threshold. In addition, we monitored the GABA levels in nonresponding and sham-stimulated rats. ⋯ Our results indicate that the development of allodynia, a common symptom in neuropathic pain states, may be linked to a decreased spinal release of GABA. We suggest that an SCS-induced release of GABA could be important for the suppression of allodynia observed in rats after SCS. Similar mechanisms could also be involved in the SCS-induced alleviation of pain in patients with peripheral neuropathy.
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To determine the indications for, efficacy of, and safety of depth electrode placement using magnetic resonance imaging (MRI)-guided stereotactic surgery in patients with intractable epilepsy. ⋯ We have found intracerebral electrode placement to be as safe as subdural strip electrode placement and have found combined depth and strip electrode monitoring to be highly effective in localizing the onset zones of complex partial seizures. Intracranial monitoring was particularly useful in the detection of a single ictal onset zone in the absence of neuroimaging abnormality and in the definitive diagnosis of bilateral independent ictal onset zones in the temporal lobe epilepsy syndrome. The specific technical aspects of the procedure that contribute to a successful outcome are reviewed. A comparison with earlier reported series suggests that MRI-guided stereotaxy and pial inspection may reduce complications of depth electrode placement.
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The current members of the faculty at the University of Chicago are acutely aware of the great historic tradition they have inherited. Like all academic medical centers, they are challenged by the current socioeconomic climate, but with the vast intellectual resources of the University of Chicago and its secure place in the community, both locally and nationally, we are confident of our ability to make a continuing contribution to the development of neurosurgery.
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This study analyzed selection criteria, clinical outcome, and tumor growth rates in patients with acoustic neuromas in whom the initial management strategy was observation. ⋯ Observation is a reasonable management strategy in carefully selected patients with acoustic neuromas. Diligent follow-up with serial magnetic resonance imaging is recommended, because some tumors will enlarge to the point at which active treatment is required.
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Associations between psychological and physical states are understood to exist, and the development of standardized psychological tests has allowed quantitative evaluation of this relationship. We tested whether associations exist between psychological test instruments and patients selected for therapeutic trials of spinal cord stimulation (SCS) for chronic, intractable pain. ⋯ Because our study population was selected on the basis of recognized prognostic factors and long clinical experience, it may not be possible to generalize our findings to the overall pain clinic referral population. In the subpopulation we have chosen for SCS trials, psychological testing is of modest value and explains little of the observed variance in outcome. We find little evidence for selecting patients for SCS on the basis of psychological testing. Because self-reported outcome measures may themselves reflect the patient's psychological state, these findings should be considered carefully, in overall clinical context. A prospective study with additional objective outcome measures is underway, which will address some of these issues.