Neurosurgery
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Intracranial section of the glossopharyngeal and upper vagal rootlets for the treatment of vagoglossopharyngeal neuralgia may cause dysphagia or vocal cord paralysis from injury to the motor vagal rootlets in 10% to 20% of cases. To minimize this complication, we recently applied a technique of intraoperative monitoring of the vagus nerve (previously described by Lipton and McCaffery to monitor the recurrent laryngeal nerve during thyroid surgery) in a patient undergoing intracranial rhizotomy for vagoglossopharyngeal neuralgia. ⋯ In this patient, the technique allowed us to preserve a rostral vagal rootlet, which if sectioned, could have caused dysphagia or vocal cord paralysis. We conclude that intraoperative monitoring of the rostral vagal rootlets is an important technique to minimize complications of upper vagal rhizotomy.
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Electric spinal cord stimulation (SCS) is widely used as a treatment modality for ischemic pain in peripheral arterial insufficiency. The background for the therapeutic effect may be a temporary inhibition of sympathetically maintained peripheral vasoconstriction. In this series of experiments, the involvement of different types of cholinergic and adrenergic receptor subclasses in the vasodilatory effect was explored in anesthetized rats. ⋯ The vasodilatory effect of SCS in the animal model used here seems to a large extent to be mediated by an inhibitory effect on peripheral vasoconstriction maintained via efferent sympathetic activity involving nicotinic transmission in the ganglia and the postganglionic alpha 1-adrenoreceptors. The involvement of beta-receptors seems to be different in skin and muscle, beta 1 being more important for the changes in the skin and beta 2 being more important for those in muscle. The high-intensity antidromic response, earlier believed to explain how SCS exerted its vasodilatory effect, was resistant to cholinergic and adrenergic manipulations and seems to depend on entirely different mechanisms.
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Most shunt-dependent hydrocephalic patients present with predictable symptoms of headache and mental status changes when their cerebrospinal fluid shunts malfunction. Their intracranial pressure (ICP) is usually high, and they usually respond to routine shunt revision. This report describes 12 shunted patients who were admitted with the full-blown hydrocephalic syndrome but with low to low-normal ICP. ⋯ All 11 were subsequently treated successfully with a new medium- or low-pressure shunt. One patient was treated successfully with prolonged shunt pumping. We postulate that: 1) the development of this low-pressure hydrocephalic state is related to alteration of the viscoelastic modulus of the brain, secondary to expulsion of extracellular water from the brain parenchyma, and to structural changes in brain tissues due to prolonged overstretching; 2) certain patients are susceptible to developing low-pressure hydrocephalic state because of an innate low brain elasticity due to bioatrophic changes; 3) low-pressure hydrocephalic state symptoms are due not to pressure changes but to brain tissue distortion and cortical ischemia secondary to severe ventricular distortion and elevated radial compressive stresses within the brain; and 4) treatment must be directed toward allowing the entry of water into the brain parenchyma and the restoration of baseline brain viscoelasticity.
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Endoscopic resection of a cavernous angioma at the subthalamic region was performed in a 33-year-old woman who presented with diplopia and progressive hemiparesis caused by recurrent hemorrhages. The entire surgical procedure was done through an 8-mm guiding tube inserted stereotactically from a frontal burr hole via an approach that traversed the anterior limb of the internal capsule. The patient's symptoms improved after surgery. This is believed to be the first report describing successful resection of a cavernous angioma located at the subthalamic region.
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Biography Historical Article
Historical perspective. David Ferrier (1843-1928).