Journal of neurosurgery
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Journal of neurosurgery · Oct 1975
Percutaneous trial of stimulation for patient selection for implantable stimulating devices.
The author describes a flexible electrode which can be inserted percutaneously for a period of several days in candidates for an implantable electrical stimulating device for pain relief. This allows the patient a trial of stimulation which closely mimics that of the intended implantable system. If this trial does not give adequate pain relief in a variety of situations, the patient is not considered to be a suitable candidate for an implantable device. The trial of stimulation in no way obviates the need for careful scrutiny of the social and psychological factors accompanying chronic pain problems.
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Journal of neurosurgery · Oct 1975
Experimental hydrosyringomyelia, ischemic myelopathy, and syringomyelia.
The authors found that cavities in the spinal cord of dogs appearing after the intracisternal administration of kaolin are not due to ischemic softening, but rather to distention and subsequent rupture of the central canal. Ischemic lesions could be produced and were found to have a quite different histopathology; this supports the hydrodynamic hypothesis of cavitary myelopathy following adhesive arachnoiditis, probably as a compensatory mechanism to the associated hydrocephalus. The similarities to human syringomyelia are discussed.
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Journal of neurosurgery · Oct 1975
Effects of increased intracranial pressure on cerebral blood volume, blood flow, and oxygen utilization in monkeys.
The relationship of cerebral blood volume (CBV) to cerebral perfusion pressure (CPP), cerebral blood flow (CBF), and the cerebral metabolic rate for oxygen (CMRO2) was examined in rhesus monkeys. In vivo tracer methods employing radioactive oxygen-15 were used to measure CBV, CBF, and CMRO2. Cerebral perfusion pressure was decreased by raising the intracranial pressure (ICP) by infusion of artificial cerebrospinal fluid (CSF) into the cisterna magna. ⋯ For comparison, CPP was lowered by reducing mean arterial blood pressure in a second group of monkeys. Only CBF was measured in this group. In this second group of animals, the lower limit of CBF autoregulation was reached at a higher CPP (CPP approximately to 80 torr) than when an increase in ICP was employed (CPP approximately to 30 torr).
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Journal of neurosurgery · Aug 1975
Computer-assisted analysis of intraventricular pressure after mannitol administration.
The effect of prolonged mannitol infusion upon intraventricular pressure was investigated with the aid of a specially-designed automatic digital recording system; the data recorded were processed off-line by a minicomputer. The character of the pressure curves is thought to result from interaction between the mannitol effect and the observed system's shifting equilibrium position, which is caused by other factors. The character of the pressure curves prior to mannitol infusion must be taken into consideration in estimating the actual effect of the drug; the authors suggest that in certain cases it might be possible to decrease further the rate of mannitol administration. The advantages of statistical approach to the evaluation of intracranial pressure variations are discussed.