Neurosurgery
-
Case Reports Comparative Study
The frequency-dependent behavior of cerebral autoregulation.
Cerebral autoregulation is a complex physiological process composed of both fast and slow components that may respond differently to different rates and patterns of blood pressure variation. To assess the temporal nature of autoregulation, transcranial Doppler velocity recordings of the middle cerebral artery obtained over prolonged periods were compared with blood pressure recordings in 5 patients without cerebral disease and in 13 patients with intracranial pathological changes. Correlations between the velocity and pressure wave forms at various frequencies of variation were measured with systems analysis techniques. ⋯ Patients without cerebral disease had significantly lower correlations (P less than 0.01), indicating intact autoregulation. Examples of increasing correlations and correlations at new frequencies emerging as the clinical condition worsened are given. These preliminary examples suggest that the application of systems analysis techniques to velocity and pressure data allow measurement of the temporal nature of cerebral autoregulation.
-
Multiple intracranial tumors of different cell types are rare. We report nine patients with multiple intracranial tumors, who did not have a history of trauma, irradiation, or phacomatosis. The clinical, radiological, and histopathological findings as well as indications for operations in patients with asymptomatic second tumors are discussed.
-
Case Reports
The effect of arteriovenous malformation resection on cerebrovascular reactivity to carbon dioxide.
To investigate the cerebral hemodynamic changes associated with obliteration of arteriovenous malformations (AVMs), we studied 26 patients undergoing total microsurgical AVM resection during isoflurane and N2/O2 anesthesia. Detectors were placed 5 to 6 cm from the margin of the lesion and in a homologous contralateral position. Cerebral blood flow (CBF) was measured using the intravenous xenon-133 technique before and after AVM resection, during both hypocapnia and normocapnia at each stage. ⋯ One patient suffered postoperative intracerebral hemorrhage, attributable to technical problems, and had no increase in CBF. We conclude that, with an acute increase in the arteriovenous pressure gradient (and cerebral perfusion pressure) that results from shunt obliteration, there is an immediate global effect of AVM resection to increase CBF. Cerebrovascular reactivity to CO2 remains intact both before and after excision.
-
Case Reports
An extreme lateral approach to intradural lesions of the cervical spine and foramen magnum.
Meningiomas and neurofibromas are the most common intradural extramedullary tumors of the foramen magnum and cervical spine. Many of these tumors are located ventral or ventrolateral to the spinal cord and medulla. Posterior approaches, although adequate for the management of most of these tumors, can sometimes result in incomplete removal of the tumor and exacerbation of the neurological deficits. ⋯ The entire longitudinal and lateral extent of the tumor and also its extradural extension can be can be managed by this approach. This approach can be considered in such a group of patients harboring entirely ventral or recurrent tumors for which the conventional posterior approach has failed. Six patients who underwent this procedure are described to illustrate its application.
-
Case Reports
Acute spinal intradural extramedullary hematoma: a nonsurgical approach for spinal cord decompression.
The authors present the case of a 60-year old man with a spontaneous spinal intradural hematoma in the thoracic and lumbar region, which was caused by anticoagulant therapy and led to a severe progressive transverse lesion. After substitution of coagulation factors, a small catheter was inserted into the subarachnoid space via a lumbar puncture. By alternating irrigation and suction removal of the blood clot, restoration of the cerebrospinal fluid passage was possible along with a marked improvement in the neurological deficits. At 8 months' follow-up, the patient had completely recovered from the severe paraparesis and bladder dysfunction.