Neurosurgery
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Magerl's technique of combining C1-C2 posterior screw fixation with a supplemental bone-wire fusion has been advocated for the management of atlanto-axial instability. Between October 1990 and August 1992, a modification of this technique was used in the treatment of 22 patients with this disorder. In the absence of spinal deformity or neoplastic disease, screw fixation and bony fusion were used alone without associated wiring, thus avoiding the risk of neural injury resulting from the sublaminar passage of wire and the retrodisplacement of ventral structures. ⋯ The one intraoperative complication was an inability to achieve secure screw purchase on one side that required unilateral screw placement with a Gallie fusion-using cable. Postoperative complications included one patient with a superficial wound infection that resolved after local debridement and antibiotics and suboccipital numbness in two patients. Progression of spinal deformity, screw pullout or breakage, and neurological or vascular complications did not occur.(ABSTRACT TRUNCATED AT 250 WORDS)
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Considerable evidence indicates that brain temperature during ischemia affects the extent and distribution of ischemic injury. However, only limited data have been presented concerning the influence of temperature on ischemic damage after reversible focal cerebral ischemia. Because focal ischemic events of this type resemble conditions observed in the clinic, studies were undertaken to examine the effects of mild and moderate hypothermia on the extent of cerebral infarction after focal neocortical ischemia. ⋯ The following groups with different intraischemic temporal muscle temperatures were analyzed: 1) control, 35.8 to 36.2 degrees C; 2) mild hypothermia, 33.0 to 33.5 degrees C; and 3) moderate hypothermia, 27.5 to 29.2 degrees C. The volumes of infarction were 214.5 +/- 17.9, 166.5 +/- 6.8, and 108.2 +/- 5.9 mm3 (mean +/- SEM) for the control, mild hypothermia, and moderate hypothermia groups, respectively. These findings demonstrate that both mild and moderate hypothermia reduce the impact of temporary focal ischemia in Sprague-Dawley rats.
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Giant cell tumors of the skull are very rare and usually occur in the sphenoid bone. The authors report the case of a 10-year-old boy with such a tumor involving exclusively the roof of the left orbit. ⋯ Computed tomographic examination and magnetic resonance imaging delineated the lesion, which was radically removed via a left fronto-orbital craniotomy. Some aspects of this rare neoplasm are reviewed.
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To successfully match the treatment to the cause for raised intracranial pressure (ICP) after a severe head injury, it is important to know the underlying mechanism at a given moment for the raised pressure. In particular, it is important to distinguish between active cerebral vasodilation, indicating functional autoregulation, and a passive vascular dilation as the cause for raised ICP. An experimental study was performed in feline models of diffusely raised ICP (n = 6), of active arterial vasodilation caused by arterial hypercarbia (n = 6), and of passive arterial dilation caused by pharmacologically induced arterial hypertension (n = 6) to determine if wave form analysis of ICP can distinguish active from passive arteriolar vasodilation. ⋯ After arterial hypertension, caused by the infusion of angiotensin II, where there was loss of myogenic tone, an increased low-frequency CVPT was accompanied by a positive phase shift (P < 0.01). These data demonstrate it may be possible to distinguish active arteriolar vasodilation from a passive loss of autoregulatory vascular tone through simultaneous measurement of the low-frequency CVPT and phase shift. Analysis of the ICP wave form provides information relevant to the management of raised ICP.