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Biomedical subjects

M Yoneya

Publications and source records attributed to M Yoneya.

6 recordsLinked to original sources

[Ventriculoperitoneal shunts with the use of pressure-adjustable valve in the management of hydrocephalus].

Sixteen patients with hydrocephalus of varied etiology who underwent ventriculo-peritoneal shunts utilizing pressure-adjustable valves were reviewed, and the usefulness of the pressure-adjustable valve in the management of hydrocephalus was evaluated. Before shunting all patients had CT evidence of hydrocephalus with Evans' Index greater than 30%. High-, medium- and low-pressure settings were chosen in 3, 11 and 2 patients respectively, according to the CSF pressure as measured during lumber puncture or ventricular drainage. Following the shunting procedures with programmable pressure valves, hydrocephalus was alleviated with Evans' Index being 27% on the average, as evaluated by CT scans. Such clinical symptoms as disturbed consciousness, dementia and increased intracranial pressure all subsided. There were no mortality, infection or revision during the follow-up period of 5 to 16 months. Of particular note was that, among these 16 cases, there were three illustrative cases in which programmable pressure valves were found useful in coping with newly developed subdural effusion and low-intracranial-pressure syndrome, by manually adjusting the valves to higher pressure settings.

Adult

Composed dynamic topography for spike and sharp wave.

We reported two kinds of dynamic topographies. In one, an interspike interval histogram and a computerized topography of the EEG basic activity were composed. In the other, spike and sharp wave characteristics were composed of an isopotential topography. These topographies enabled us to observe serial changes in epileptic discharge dynamically by 1 msec.

Brain Mapping

Pituitary enlargement associated with Addison's disease.

We report a case of Addison's disease with pituitary enlargement which could easily have been misinterpreted as a pituitary adenoma or other pituitary disease. Serial computed tomography following replacement therapy was essential to confirm the diagnosis.

Addison Disease

Association of arteriovenous malformation and intracranial aneurysm in the posterior fossa.

Two cases of a saccular aneurysm of the posterior inferior cerebellar artery associated with an anatomically related arteriovenous malformation are presented. The aneurysms were clipped and the arteriovenous malformations were totally extirpated in one-stage operations in both cases. The association of arteriovenous malformation and arterial aneurysm in the posterior fossa was reviewed in the literature.

Cerebellum