Neurosurgery
-
Randomized Controlled Trial Comparative Study Clinical Trial
Propylene glycol toxicity following continuous etomidate infusion for the control of refractory cerebral edema.
Continued elevations in Intracranial Pressure (ICP) following traumatic or ischemic compromise are known to cause markedly increased morbidity and mortality. Because of the side effects of barbiturates including hypotension and prolonged recovery time, the use of shorter-acting anesthetic agents to control ICP has been considered. Etomidate, when administered by continuous infusion, has been shown to decrease cerebral metabolism resulting in a secondary decrease in cerebral blood flow with minimal changes in cerebral perfusion pressure. ⋯ All patients also received dexamethasone 2 mg IV every six hours to prevent the adrenocortical insufficiency that might occur as a consequence of etomidate-induced suppression of cortisol synthesis. Intracranial pressure decreased (mean = 12mmHg) following the initiation of etomidate. Cardiac parameters remained unchanged (cardiac output 4.8 +/- .6 liters/min).(ABSTRACT TRUNCATED AT 250 WORDS)
-
Degenerative central lumbar stenosis has traditionally been considered to be a result of bony narrowing of the spinal canal. In two consecutive patients with degenerative central lumbar stenosis and complete myelographic blocks, the cauda equina was compressed by a thickened ligamentum flavum (cross-sectional area [CSA], > 150 mm2). This ligamentous stenosis occurred within bony canals of normal dimensions (anteroposterior diameter, interpediculate distance, interfacet distance, and CSA). ⋯ Excision of the thickened ligamentum flavum restored the dural sac to normal (CSA, 130-230 mm2), and both patients received relief from their symptoms. Unilateral laminotomy was used successfully to achieve bilateral ligamentectomy. Therefore, in a well-defined subgroup of patients with degenerative central lumbar stenosis, the dural sac can be decompressed by selective resection of the ligamentum flavum, and bilateral ligamentectomy can be performed via unilateral laminotomy.
-
Thoracic pedicle anatomy (interpedicular distance, transverse and sagittal pedicle widths, transverse and sagittal pedicle angles, and the distance from the axis of the pedicle to the axis of the transverse process) was assessed in 11 cadavers of elderly people. The cadaveric spines were extensively dissected to augment the accuracy of the measurements via caliper and goniometer. The results were compared with those of previous studies that assessed pedicle anatomy with computed tomography, direct measurement, and three-dimensional morphometry. ⋯ This relationship gradually changes as the thoracic spine is descended, so that at T12, the transverse process is 6.6 +/- 2.4 mm caudal to the pedicle. Crossover consistently occurs at the T6-T7 region. Although the transverse process is a reliable external landmark for the location of the pedicle in the lumbar spine, this relationship in the thoracic spine is variable and only moderately predictable.
-
The possibility that the female sex steroid progesterone plays a role in meningioma proliferation has been suggested by a number of investigators, and it has been shown that many meningiomas have high-affinity progesterone binding sites. There has been a long-standing debate in the literature as to whether the progesterone receptors that are present in meningiomas are functional. We recently showed, by the use of immunohistochemistry, that the progesterone receptor in meningiomas is localized to the nucleus, suggesting that the receptor is in a location to be activated. ⋯ In all meningioma cell cultures, an increase in the transcription of the progesterone response element construct was observed in the presence of dexamethasone, suggesting that the glucocorticoid receptor in meningiomas is functional. An increase in transcription was observed with the addition of promegestone (R5020), a progesterone agonist, only in meningioma cell cultures that were expressing the progesterone receptor. These data show that both the progesterone and the glucocorticoid receptor in meningiomas are functional and support the concept that progestins and glucocorticoids may play an important role in meningioma growth.