Neurosurgery
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To present the magnetic resonance imaging features, clinical findings, and possible embryologic bases for nonterminal myelocystoceles, a distinct subset of closed spinal dysraphisms. ⋯ The nonterminal myelocystocele is a distinct form of closed spinal dysraphism characterized by a skin-covered meningocele, which is either crossed by a fibroneurovascular stalk that extends from the dorsal aspect of the spinal cord to attach to the dome of the meningocele (abortive form, or myelocystocele manqué) or contains a hydromyelic cavity that is continuous with the ependymal canal of the spinal cord (complete form).
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An acute subdural hematoma (SDH) with a thickness greater than 10 mm or a midline shift greater than 5 mm on computed tomographic (CT) scan should be surgically evacuated, regardless of the patient's Glasgow Coma Scale (GCS) score. All patients with acute SDH in coma (GCS score less than 9) should undergo intracranial pressure (ICP) monitoring. A comatose patient (GCS score less than 9) with an SDH less than 10-mm thick and a midline shift less than 5 mm should undergo surgical evacuation of the lesion if the GCS score decreased between the time of injury and hospital admission by 2 or more points on the GCS and/or the patient presents with asymmetric or fixed and dilated pupils and/or the ICP exceeds 20 mm Hg. ⋯ If surgical evacuation of an acute SDH in a comatose patient (GCS < 9) is indicated, it should be performed using a craniotomy with or without bone flap removal and duraplasty.
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We performed a biomechanical comparison of several C1 to C2 fixation techniques including crossed laminar (intralaminar) screw fixation, anterior C1 to C2 transarticular screw fixation, C1 to 2 pedicle screw fixation, and posterior C1 to C2 transarticular screw fixation. ⋯ All four screw fixation techniques limit motion at the C1 to 2 articulation. The addition of cable fixation improves resistance to flexion and extension for posterior transarticular screw fixation.
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Patients with mass effect on computed tomographic (CT) scan or with neurological dysfunction or deterioration referable to the lesion should undergo operative intervention. Mass effect on CT scan is defined as distortion, dislocation, or obliteration of the fourth ventricle; compression or loss of visualization of the basal cisterns, or the presence of obstructive hydrocephalus. Patients with lesions and no significant mass effect on CT scan and without signs of neurological dysfunction may be managed by close observation and serial imaging. ⋯ Suboccipital craniectomy is the predominant method reported for evacuation of posterior fossa mass lesions, and is therefore recommended.
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Biography Historical Article
An essay concerning human understanding: how the cerebri anatome of Thomas Willis influenced John Locke.
Neurosurgeons are familiar with the anatomic investigations of Thomas Willis, but his intellectual legacy actually extends into the arena of philosophy. John Locke was a student of Willis while at Oxford, and this essay explores how some of Willis's anatomic discoveries might have influenced the ideas Locke expressed in his Essay Concerning Human Understanding. It also includes historical information about 17th century England and the group of men (including Christopher Wren and Robert Boyle) who worked with Willis and founded the Oxford Experimental Philosophy Club, which became the Royal Society.