摘要:

&NA;There is a need to monitor the functional status of the motor pathways well enough to predict the state of that function during operations and in injured or diseased patients. We previously reported that a motor evoked potential (MEP) can be produced by direct or transcranial stimulation of the motor cortex in both cats and humans. This signal descends through both the dorsolateral and ventral spinal cord and is primarily localized in the pyramidal tracts, producing a peripheral nerve signal and an electromyogram (EMG) response. It is more sensitive to injury than the somatosensory evoked potential (SEP). We report here that one can stimulate the cerebellar cortex, either directly or transcranially, and produce a descending signal in the spinal cord that has different characteristics from the MEP. The cerebellar evoked potential (CEP), located in the dorsolateral and the ventral cord, has an earlier latency and a faster conduction velocity than the MEP. It is predominantly ipsilateral with some contralateral components and also produces EMG responses. In the peripheral nerves, the CEP often produces a pattern of several waves that is different from the one or two predominant contralateral waves of the MEP. The CEP is not diminished by pyramidotomy. It arises from two sites on the cerebellar cortex, medial and lateral. The pathways activated may be the vestibulospinal, rubrospinal, reticulospinal, and fastigiospinal systems. This test seems to offer a monitor of selected motor pathways in the spinal cord largely separate from and complementary to the MEP. The ventral pathways activated probably incude those demonstrated to be most essential to basic ambulation after spinal cord injury in primates. Also of importance, one type of evoked potential can facilitate another, which provides additional diagnostic tests. The CEP should be of investigative and clinical value. (Neurosurgery19:163‐176, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;The effects of experimental subarachnoid hemorrhage (SAH) on the blood‐arterial wall barrier in the basilar arteries were studied during the acute stage after SAH. SAH was induced in rats by injecting fresh autologous blood into the cisterna magna. Horseradish peroxidase (HRP) was given intravenously before killing the animals to assess the integrity of the barrier. In the basilar arteries taken from the animals that were killed 30 minutes after the cisternal injection of either mock cerebrospinal fluid or arterial blood, HRP reaction products were diffusely observed in the subendothelial spaces and smooth muscle layers. At 5 hours after the blood injection, no permeation of HRP into the subendothelial space was observed. Endothelial cell transcytosis seemed to be the important mechanism for HRP permeation into the subendothelial space rather than the opening of interendothelial junctions. The disruption of the blood‐arterial wall barrier in the major cerebral arteries after SAH may be involved in the pathogenesis of vasospasm. (Neurosurgery19:177‐184, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;This report presents an experimental model for study of the cellular and molecular biology of invasiveness in tumors. It uses SV40 virus for the production of primary intracranial tumors that are invasive for normal brain and vary markedly and predictably in this invasiveness. Cell cultures of dissociated 1‐ to 2‐day‐old Syrian hamster cerebral cortex (Cx), brain stem (Bs), cerebellar hemisphere (Cbh), and cerebellar vermis (Cbv) were transformed with SV40 virus and inoculated intracerebrally into newborn hamsters. All 368 animals that developed intracranial tumors were killed, and tumor was taken for histological and immunofluorescence studies, assessment of extent of invasiveness, and preparation of cell cultures from which cells were cloned by dilution plating or growth in soft agar. A few hamsters were perfused with glutaraldehyde for studies of tumor ultrastructure. All cloned and uncloned tumor cells were reinoculated to produce second‐ and third‐passage tumors. Characteristic differences in morphology and growth rate were observed between normal astrocytes derived from each brain region, and these phenotypic differences were retained after virus transformation and tumor production. Cloned and uncloned Cx cell‐derived tumors of second and third passage diffusely invaded adjacent normal brain, although those of first passage invaded only slightly. Except for extracerebral spread, these tumors resembled human astrocytic series tumors. Bs and some Cbh cell‐derived tumors were also astrocytic but more undifferentiated and only slightly invasive; Cbv and other Cbh cell‐derived tumors were sarcomatous and only extended along perivascular spaces or were not invasive at all. The tumor cells contained glial fibrillary acidic protein and SV40 T‐antigen. These results suggest that astrocytes from different brain regions vary in genomic stability and support the theory that differences in invasiveness reflect the development of heterogeneity and subsequent selection of more aggressive subpopulations of cells. (Neurosurgery) 19:185‐200, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;Motilin, a gut peptide recently demonstrated in the mammalian brain and anterior pituitary, was localized immunocytochemically in rat, guinea pig, and human anterior pituitary glands with two antisera to synthetic porcine motilin. Adjacent sections of normal glands were immunostained for motilin, growth hormone, and prolactin reactivity. Motilin reactivity was consistently seen in somatotrophic regions of the mammalian glands and in many instances was colocalized in individual somatotrophs traced in adjacent sections stained for growth hormone. There was no motilin activity discerned in prolactin‐secreting regions of the gland. These studies reinforce the close relationship of motilin or a motilin‐like peptide with growth hormone in normal somatotrophs. Further anatomical and in vitro studies with tumor material will be useful in elucidating the physiological relationship of motilin to growth hormone. (Neurosurgery19:201‐204, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;The use of intraoperative spinal ultrasonography in 14 cases and its effect on decision making during laminectomy procedures is discussed. The advantages of the technique in operations for syringomyelia, trauma, spondylosis, intramedullary tumors, and neuroablative procedures of the spinal cord are elaborated. (Neurosurgery19:205‐211, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;Six cases of ossification of the posterior longitudinal ligament (OPLL) in Caucasians have been diagnosed during a 2‐year period at Walter Reed Army Medical Center. Five cases were in men and one was in a woman. Three cases presented as myelopathy and three as radiculopathy. Diagnosis was best confirmed with computer‐assisted tomography. All six cases were treated surgically via an anterior approach, microsurgical resection of the OPLL, and autograft fusion. Patients with radiculopathy had immediate pain relief after operation. Those with myelopathy required vertebrectomy and regained strength after operation. All patients improved with operation. OPLL is not a rare condition in Caucasians. With diagnosis and proper surgical intervention, prognosis for improvement is good. (Neurosurgery19:212‐217, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;The authors present seven cases of spinal trauma at the T‐12‐L‐1 level with severe spinal canal stenosis secondary to compressive, anterior discocorporeal lesions. Associated neurological disorders were of varying severity. Six cases were investigated by computed tomography, which enabled the degree of thoracolumbar spinal canal stenosis to be determined. In all cases, the surgical procedure involved rectification of spinal deformity, with an initial unilateral posterolateral approach permitting anterior spinal canal recalibration, either by impaction of protrusive fragments or ablation of ejected disc fragments. The stabilization was in all cases achieved by complimentary bilateral plates using Roy‐Camille material, associated with posterolateral arthrodesis by grafting with reconstruction of the articulopedicular structure. The functional spinal result was excellent in all cases, and recalibration was verified by tomography. In those cases showing neurological deficiency, good and early recovery was attributable to the suppression of spinal canal stenosis. The application of this posterolateral approach for severe lesions of the thoracolumbar junction seems to represent, in all cases of recent lesions, an alternative to the anterior or combined methods, which present widely recognized difficulties at the thoracoabdominal junction. (Neurosurgery19:218‐227, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;Premature closure of the metopic suture results in a deformity ranging from a minor variation to a severe cosmetic deformity. The three principal abnormalities comprising metopic synostosis are trigonocephaly secondary to the restriction of growth of both frontal bones, deficient lateral supraorbital rims, and hypotelorism. Seventeen of 18 patients evaluated for metopic synostosis had surgical correction of their anomalies. For a minor degree of prominence at the metopic suture, a bicoronal flap followed by shaping at the suture with a shaping burr was sufficient and yielded favorable cosmetic results. A more extensive procedure for cosmetic resolution of trigonocephaly and hypotelorism was required for those patients with more pronounced deformities. In patients with moderate to severe metopic synostosis, the following procedures were important in achieving excellent cosmetic results: (a) a bicoronal subgaleal flap down to the supraorbital rims with preservation of continuity of pericranium with an intact periorbita; (b) bifrontal craniotomy with complete removal of the metopic suture; (c) dural plication in midline to achieve an immediate aesthetically pleasing contour; (d) removal or remodeling of the supraorbital rims and nasion with replacement of the remodeled frontal bone anteriorly in order to rebuild the orbital rim and release the supraorbital bar from the anterior cranial base; and (e) securement of the bifrontal bones anteriorly and laterally, but not posteriorly, to allow further anterior and lateral displacement of the supralateral orbital margin. (Neurosurgery19:228‐234, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;Delayed ischemic deficits from vasospasm after subarachnoid hemorrhage remain a major source of death and disability to patients surviving subarachnoid hemorrhage. Ideal treatment for this condition would prevent or reverse spasm in major subarachnoid vessels. This goal remains elusive. Considerable success has been obtained with augmentation of flow in ischemic regions by induced hypertension and hypervolemia. Some patients are not good candidates for this therapy because of underlying cardiovascular disease or the presence of unsecured aneurysms. A total of 11 patients have recently undergone extracranial‐intracranial bypass for the treatment of symptomatic vasospasm. Bypass was performed in 4 patients due to failure of medical management and in 7 patients due to our reluctance to induce hypertension in the setting of unsecured aneurysms. Eight of the 11 patients responded neurologically to the bypass procedure within 24 hours. In 6 cases, neurological deficits either improved or resolved. After operation, all 8 patients maintained their preoperative neurological status with lower mean arterial blood pressures than before bypass. Noncomatose patients with focal middle cerebral ischemic deficits and secured aneurysms in whom medical management has failed or in whom these measures are contraindicated may indeed benefit from extracranial‐intracranial bypass. Patients with unsecured aneurysms remote from an ischemic middle cerebral territory should probably be revascularized if cautious hypertension fails to improve their conditions. (Neurosurgery19:235‐246, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

&NA;The clinical and diagnostic findings in 13 patients with leptomeningeal metastasis from supratentorial malignant gliomas are reported. Criteria for inclusion in this study were positive myelographic examination, positive cerebrospinal fluid cytology on two or more samples, or evidence of leptomeningeal seeding at autopsy. Eight patients had premortem symptoms of leptomeningeal metastasis, with the diagnosis confirmed during life in 5 patients. Average survival after the onset of symptoms was 3 months (range, 1 to 5 months). Comparison of the autopsied group with 10 concurrent autopsied patients without leptomeningeal gliomatosis did not reveal any significant differences in age, but leptomeningeal gliomatosis was more prevalent in patients with longer postoperative survival. Leptomeningeal involvement at autopsy was more extensive in symptomatic patients. Cerebrospinal fluid examination often gave nondiagnostic or nonspecific results. Computed tomography of the brain showed evidence of ventriculomegaly, periventricular contrast enhancement, or multifocal tumor involvement in every case. Iophendylate myelography was the most reliable diagnostic tool and established the diagnosis whenever performed. The natural history and clinical significance of leptomeningeal metastasis from supratentorial malignant gliomas are discussed. (Neurosurgery19:247‐251, 1986)

ISSN:0148-396X    

出版商:OVID    

年代:1986

数据来源: OVID