Takashi Hatayama

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The short- and long-term effects of static compression of the cochlear nerve were studied in dogs. The nerve was exposed in the cerebellopontine angle and a modified aneurysm clip was applied to reduce the diameter of the nerve trunk to 50%, 40%, 30% or 20% of normal (designated respectively as 50%, 60%, 70%, and 80% compression). Brainstem auditory evoked(More)
The authors describe the histopathological findings in a case involving rerupture of a recanalized aneurysm of the internal carotid artery 8 months after partial (95%) embolization with interlocking detachable coils. The aneurysm was filled with poorly organized thrombus, and its orifice was devoid of endothelial cells. It appears likely that a long period(More)
Pineal parenchymal tumors are so rare that their responses to radiation and/or chemotherapy are not well known. Two cases of pineocytoma, which responded well to radiation therapy and chemotherapy, are reported. A 45-year-old female received radiation therapy in a total dose of 5000 rads to the tumor. Three months after the completion of therapy, computed(More)
We investigated whether methylprednisolone sodium succinate can ameliorate cochlear nerve degeneration following compression injury on the cerebellopontine angle portion of the cochlear nerve, using a quantitative animal experimental model that we have developed recently. In this model, cochlear nerve degeneration after compression could be quantitatively(More)
OBJECTIVE Transcranial Doppler (TCD) findings for evaluation of the severity of vasospasm (VSP) in patients with ruptured aneurysmal subarachnoid hemorrhage are controversial. To clarify these TCD findings, intra-arterial digital subtraction angiography was used to simultaneously investigate the angiographic features of cerebral vessels and the cerebral(More)
During 22 operations in 18 patients, we stimulated the ocular motor nerves electrically, intracranially, and recorded compound muscle action potentials (CMAP) directly from the extraocular muscles with a ring electrode that we developed. Recording electrodes were applied in 52 instances to the superior rectus, medial rectus, superior oblique, or lateral(More)
Two cases of ruptured distal anterior cerebral-artery aneurysms presenting with acute subdural hematoma are reported. Case 1 was a 55-year-old male, who showed abrupt disturbance of consciousness. An emergency CT revealed acute subdural hematoma at the right parietal convexity and interhemispheric fissure with moderate midline shift. There was no evidence(More)
A rare case of primary pineal melanoma is reported. The patient was a 53-year-old woman who complained of a severe headache. Computed tomography and magnetic resonance images revealed obstructive hydrocephalus caused by a mass lesion in the pineal region. A biopsy was performed through an occipital transtentorial approach. A black pigmented solitary tumor(More)
Delayed vasospasm due to ruptured aneurysm has been basically evaluated by angiographic changes in contrast to clinical features such as delayed ischemic neurological deficits (DIND). However, the discrepancies between angiographic and clinical findings have been pointed out. In this study, angiographic changes and cerebral circulation time in ruptured(More)
A ring-shaped electrode was developed and used in 20 patients to record evoked electromyographic responses directly from the extraocular muscles during skull base surgery. Intra-operative monitoring with this electrode helps the surgeon to localize the nerves that innervate the extraocular muscles precisely and to refrain from disturbing important neural(More)