Neurosurgery
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Review Comparative Study
Vestibular schwannoma management in the next century: a radiosurgical perspective.
To discuss how the evolution of vestibular schwannoma radiosurgery, changes in health care delivery, and patient accessibility to medical information will affect the management of vestibular schwannomas in the future. ⋯ Early data regarding vestibular schwannoma radiosurgery predicted an exponential growth curve. Although it is premature to assume that the current trend will continue, it is likely that an ever increasing percentage of patients will undergo radiosurgery as accessibility to this alternative increases, and more data are published regarding long-term tumor growth control rates. If the mathematical model proves to be accurate, then stereotactic radiosurgery will replace surgical resection as the preferred management strategy for the majority of patients with vestibular schwannomas.
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Primary central nervous system lymphoma is a disease with increasing incidence. Atypical presentations are becoming more frequent. ⋯ All four cases included atypical presentations of lymphoma. These cases again illustrate that a correct diagnosis cannot be obtained based only on imaging and clinical findings.
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There is some controversy regarding the value of intraoperative neurophysiological monitoring in predicting postoperative neurological deficits. We discuss our experience with the use of intraoperative somatosensory evoked potentials (SSEPs) during surgery of cranial base tumors. ⋯ Intraoperative SSEPs have a high positive predictive value during surgery for cranial base tumors, but they do not detect all postoperative deficits.
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Parasagittal meningiomas, especially when associated with the middle or posterior third of the superior sagittal sinus, pose difficult management challenges. Initial surgical excision is associated with high morbidity and frequent tumor recurrence after subtotal resection. Neurological deficits are cumulative when multiple resections are required. No consistent management approach exists for patients with such tumors. In addition to observation, management options include resection, stereotactic radiosurgery, or fractionated radiation therapy used alone or in combination. ⋯ In patients with smaller tumors (<3 cm in diameter) and patent sagittal sinuses, we advocate radiosurgery alone as the first surgical procedure. Patients with larger tumors and those with progressive neurological deficits resulting from brain compression should first undergo resection. Planned second-stage radiosurgery should be performed soon afterward for any residual tumor nodule or neoplastic dural remnant. Multimodality management may enhance long-term tumor control, reduce the need for multiple resections, and maintain the functional status of the patient.
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This study was undertaken to examine the pathophysiological mechanisms of trigeminal neuralgia and the mechanisms underlying pain relief after percutaneous retrogasserian glycerol rhizolysis (PRGR). ⋯ Partial deafferentation, with impairment of thin (C/Adelta) and thick (Abeta) fiber-mediated sensations and abnormal temporal summation of pain, is present in the trigger area of patients with trigeminal neuralgia. Relief of pain after PRGR depends on the normalization of abnormal temporal summation of pain, which is independent of general impairment of sensory perception. Assessment of the temporal summation of pain may serve as an important tool to record central neuronal hyperexcitability, which may play a key role in the pathophysiological changes in trigeminal neuralgia.