Haemorrhage in regions remote from the site of following intracranial operations is rare, but they do occur. We performed supratentorial craniotomy on 639 patients between the time of introduction of computed tomography (CT) for clinical use in 1983 and June 1992; subarachnoid haemorrhage (SAH) in the posterior fossa occurred postoperatively in six of these cases. These included four patients with tumours in the sellar region, one with an arteriovenous malformation (AVM) and one who underwent superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis. The ages of the six patients ranged from 17-72 years. Haemorrhage occurred on the day of operation in one case and was detected on CT examination on the day following surgery in the remaining five cases. Of three patients with disturbance of consciousness, two underwent suboccipital craniectomy for reduction of intracranial pressure, while one received barbiturate therapy and later underwent cerebrospinal fluid (CSF) shunt surgery. No special treatment was necessary for the remaining three patients with less serious lesions. Five of the six patients ultimately recovered their pre-operative neurological status apart from the primary diseases. Factors inducing such haemorrhages seem likely to include displacement of the cerebellum by reduced CSF pressure during and after operations, and stretching and tearing of the veins and venules in the sulci of the tentorial surface of the cerebellum. Consideration should therefore be given to the maintenance of an appropriate CSF pressure during operation; this is particularly important in elderly patients and those with an atrophied cerebral cortex.
Eight cases of primary optic nerve sheath meningioma were treated between 1980 and 1988. Five were females aged 37-61 years. The other three were two boys, one with neurofibromatosis, and an old male aged 71 years. They were first seen by the ophthalmologist with complaints of unilateral progressive visual loss or proptosis. Although blindness of the affected eye mainly occurred between 1 month and 3 years after the initial symptoms, the diagnosis tended to be made late in the adult cases. Intracranial extension was demonstrated in four of the six adult cases when contralateral visual loss or disturbance of consciousness presented. Larger intraorbital meningiomas were easily diagnosed by a combination of computed tomographic (CT) scanning, magnetic resonance (MR) imaging, and carotid angiography. MR imaging provided clear delineation of the optic nerve and its course through the tumor, and perioptic meningioma could be diagnosed. However, it was difficult to make a diagnosis without biopsy at the early stage, for example, when just the enlargement of the optic nerve was demonstrated by CT or MR imaging. Tumor removal was performed when blindness developed after definitive diagnosis by biopsy, intracranial extension was demonstrated, and advanced proptosis presented. The transcranial supraorbital approach or transcranial transorbital approach with resection of the supraorbital rim was used for these large intraorbital meningiomas. From our clinical experience, early diagnosis and early treatment should be emphasized.
Expression of the c-fos gene in CNS induced by formalin injection into the face as pain stimulus was examined in cats. Fos-positive neurons were demonstrated in the anterior cingulate, anterior insula and other areas of the cerebral cortex bilaterally, midline thalamic nuclei, hypothalamus, and brainstem in both the formalin-injected and control group (anesthesia only). Most of these labeled regions appeared to correspond to stress-and anesthesia-related sites. The difference from the control was the finding of Fos-positive cells in the SI, possible SII and trigeminal subnucleus caudalis in the experimental group. Almost significant increase in Fos-positive cells was also observed in areas 24, 23 and the anterior agranular insular cortex in experimental cats. Our findings appear to be compatible with recently reported PET findings in man, except laterality. For full appreciation of the complex pain experience, these diverse areas of the brain appear to be activated.
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