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T Tachizawa

Publications and source records attributed to T Tachizawa.

11 recordsLinked to original sources
PubMed1987

[Stress distribution in the brain--numerical simulation by the finite element method].

The analysis of the deformation of brain and distribution of stress caused by the compression from outside would be interesting and also useful for the better understanding of the pathophysiology in the cases of intracranial hematoma and other space occupying lesions. The computerized numerical simulation using the finite element method was carried out to analyze these problems. A simple brain model of two dimensions, that was composed of the inner surface of skull, brain and lateral ventricles, was utilized and it was divided into 101 triangular elements for the calculation of finite element method by a 16-bit personal computer. The model of brain was compressed in two different ways; one was a subdural hematoma type where the force of compression was distributed over relatively wide area and the other was a epidural hematoma type where compression was localized to smaller area. In both types, the brain was compressed on the left fronto-temporal region. The deformation of brain in the subdural hematoma type model was that corresponding to the hematoma of crescent shape just as seen on the CT scan of actual case. The lateral ventricle of affected side was deformed more markedly than that of contralateral side. The midline structure of the brain was shifted to normal side and shift was larger in the portion anterior to the lateral ventricles. The stress was distributed from the area beneath the hematoma to remote location in the affected hemisphere but the propagation of stress was blocked by the falx and it was very small in the contralateral hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1983

[Spectral analysis of cerebrospinal fluid pulse wave].

The change of the cerebrospinal pressure wave from during the continuous monitoring of intracranial pressure is often experienced. We supposed that this phenomenon would be the result of the change of transmission of spinal fluid pulse through the cerebrospinal fluid (CSF) system. Our study was performed to determine the change of auto power spectrum of CSF pulse when CSF pressure was increased by the slow infusion of lactate linger solution. The spectrum of CSF pulse was found to be composed of four main waves; wave derived from the respiratory movement, fundamental wave of cardiac origin and its 2nd and 3rd harmonic waves. The power of waves derived from the cardiac beats were increased when CSF pressure was elevated by the slow infusion, but the degree of increment was larger in the fundamental wave than harmonic waves. Elevation of CSF pressure caused relative attenuation of the harmonic waves included in CSF pulse. From the result of this study we found that CSF system would have the function of "high-cut filter" and its cut-off frequency was lowered by the slow infusion of lactate linger solution.

Adult↗
PubMed1982

[Penetrating transorbital intracranial foreign body].

About a month prior to admission to our hospital, a 25-year-old man had a quarrel with his friend and was stabbed in his left eye with a cracked bottle of beer. He underwent emergency operation for the injured left eye. Subsequently he was admitted to an ophthalmological ward in our hospital for plastic surgery of an artificial eye. An intracranial foreign body was pointed out, and he was soon transferred to our neurosurgical ward. Plain x-ray films and tomograms of the skull and CT scan showed a foreign body at medial portion of the left superior orbital fissure. Carotid angiography revealed no significant implication of the cerebral vessels. As there was a strong suspicion of cerebral contusion or liquorrhea, a pterional craniotomy was so designed as to do removal of thie foreign body and repair of the dura mater in one stage. The post-operative couse was uneventful without liquorrhea or miningitis. It was emphasized that pterional approach used by Hamby (1970) for surgery of malignant exophthalmos was useful and felicitious in this case. It was additionally reported that cerebrospinal orbitorrhea observed in this case was rare and it might be the third case in the literature.

Adult↗