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Biomedical subjects

S Oi

Publications and source records attributed to S Oi.

At least 91 records · Page 5Linked to original sources

[New clinical phase in intrauterine diagnosis and therapeutic modalities of CNS anomalies].

Thirty one cases of prenatally diagnosed CSN malformations were encountered in our institutions between 1982 and 1988. There were 42 disclosed lesions including 24 hydrocephalus, 3 anencephaly, 3 myeloschisis, 3 holoprosencephaly, 3 encephalocele, 2 Dandy-Walker cyst, 1 hydroencephalodysplasia, 1 brain tumor (Teratoma), 1 sacrococcygeal teratoma and 1 sacral agenesis. The gestational age at diagnosis ranged from 24 to 40 weeks of gestation (average 33.4 weeks). All were diagnosed by ultrasonography, and either MRI or whole body CT was additionally performed to evaluate the morphology in ten patients. MRI was a definitely useful diagnostic tool to evaluate the intracranial morphology, whereas whole body CT was much superior to other diagnostic imagings to visualize the condition of cranium or cranial sutures. Using these diagnostic procedures the type of hydrocephalus, was able to be identified, according to the major categories, in the individual cases. Spine morphology, however, was not detected n such high quality by MRI. Ultrasonography combined with application of whole body CT, with or without MRI, may be the best method now available to diagnose spina bifida. However, at the present time, this cannot be done until after 24 weeks of gestational age. It is our strong impression that such diagnostic technique for fetal CNS malformations will be improved, and selection of therapeutic modalities will be decided in the prenatal period before birth in the near future. It will be a dramatic change in the clinical historical phase in the treatment of CNS malformations, but establishment of therapeutic regimen along with more precise analysis of natural history, pathophysiology, postnatal outcome and ethical aspects of these congenital anomalies is required.

Central Nervous System↗

A hypothesis for myeloschisis: overgrowth and reopening. An experimental study.

A hypothesis for embryopathogenesis of myeloschisis is described on the basis of experimental studies analyzing the stage specificity and immunohistochemical/histological characteristics of the exposed neural tissue (placode). Myeloschisis developed in six fetuses among 205 chick embryos treated in various stages with teratogens including ethylnitrosourea, and anticonvulsant and antipyretic agents. All but one case (with associated cephalothoracopagus) demonstrated myeloschisis in the thoracic region with a lamina defect of two and three levels. No fetus was exposed to a teratogen prior to or within Hamburger and Hamilton stage 12 (45 to 49 hours postincubation), when the neuropore closes. Immunohistochemical studies of chick myeloschisis clearly indicated that neuron-specific enolase-positive elements were extremely active only in the overgrown placode, corresponding to the histological findings with Kluver-Barrera's special stain. These findings were compared with observations in a case of myeloschisis in a human neonate. The results of this study imply the possibility of another mechanism for the embryopathogenesis of myeloschisis: namely, the overgrowth and reopening hypothesis.

Animals↗

Trigonocephaly (metopic synostosis). Clinical, surgical and anatomical concepts.

The clinical features, surgical and anatomical concepts based on an evaluation of the development of the anterior cranial fossa in metopic synostosis are discussed. Thirteen cases of trigonocephaly of infancy during last 4 years are described. Five children were mentally retarded. A more marked triangular cranial configuration with acute nasopterional angle was associated with more severe mental retardation and other unfavorable conditions, including cardiopulmonary disorders and chromosome anomalies. From a quantitative analysis of the anterior cranial fossa development obtained from CT measurement in comparison with values in normal infants, the following procedures appeared to be important: (1) correction of acute nasopterional angle, achieving a flat forehead; (2) forward advancement of both pterions and anterolateral parts of the frontal bones, rebuilding the orbital roof and frontal eminences; (3) shortening of the overgrown midline structure by removal of the bony ridge of the metopic suture. Our procedure on the basis of these measurements for determination of surgical intervention is described.

Craniosynostoses↗

Nasal dermal sinus and dermoid cyst with intrafalcial extension. Case report and review of literature.

Congenital nasal dermal sinus is an unusual lesion which comprises about 11%-12% of all cranial dermal sinuses. The sinus tract seldom extends intracranially and an associated intrafalcial inclusion cyst is extremely rare. The authors report a case of nasal dermal sinus and dermoid cyst with intrafalcial extension in a boy aged 1 year 4 month. Previous reports of this rare lesion are reviewed and the possible pathogenesis discussed.

Dermoid Cyst↗

Infantile hydrocephalus and the slit ventricle syndrome in early infancy.

Slit ventricle syndrome is well known as a complication in the treatment of hydrocephalus by shunting. It is generally considered to be a chronic (but not acute) complication, occurring years after the shunt procedure; there has been no report of this syndrome occurring before 1 year of age. The authors present infantile cases that developed a severe form of this syndrome shortly after shunt procedures and discuss the pathophysiology in comparison to experience with older cases. The causative factor was thought to be extremely low intracranial pressure with resultant microcephalus created by double or multiple shunt placement. The condition resulted in rapid onset of coma and respiratory arrest, which was successfully treated by subtemporal decompression or placement of an antisiphon device, with insertion of a higher pressure valve. The specific characteristics of infantile hydrocephalus are analyzed in the light of this complication from a series of 58 treated infants. In a follow-up of over 1 year in 42 cases, analysis revealed that slit ventricle occurs most frequently in immature young infants shunted before 1 month of age (85.7% or 18/21 cases). In contrast, subdural hematoma after shunting is an extremely rare phenomenon in premature or mature neonates. Slit ventricles were thought to result from high intracranial compliance due to the softer brain and more markedly widened cranial sutures of infantile hydrocephalus in the younger age group. The functioning period of the initial shunt was also much shorter in younger infants, and this may be because the ventricular shrinkage to a slit can cause shunt malfunction with or without developing the slit ventricle syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Ventricles↗

Pathophysiology of aqueductal obstruction in isolated IV ventricle after shunting.

The authors report their cases of isolated IV ventricle and discuss their concepts of secondary obstruction of the aqueduct, analyzing CSF dynamics, pressure measurements, serial CT scan changes, and the outcome of various treatment modalities. Two distinctly different categories were identified: functional obstruction in which the obstructed aqueduct reopened either as the result of decreasing the elevated infratentorial pressure (Raimondi's phenomenon) or from correction of overdrainage of the supratentorial system; permanent obstruction with pathological occlusion of the aqueduct, necessitating a IV ventriculoperitoneal shunt. It is the pathophysiology and pathoanatomy of secondary obstruction of the aqueduct that determine the specific treatment to be used in managing the isolated IV ventricle syndrome.

Brain Diseases↗

Morphological findings of postshunt slit-ventricle in experimental canine hydrocephalus. Aspects of causative factors of isolated ventricles and slit-ventricle syndrome.

The progressive status of slit-ventricle and its associated pathology may be severe, occasionally resulting in the slit-ventricle syndrome or irreversible morphological changes in the brain and CSF pathways. To analyze the morphological changes of slit-ventricles critically, comparing the human form with canine hydrocephalus, 19 dogs had kaolin injected into the cisterna magna to produce hydrocephalus. The model of slit-ventricle was created by a low pressure arrangement (external ventricular drainage with extreme siphon effect). The gross morphological appearance showed thickening of the white matter, enlarged cortical vessels, and slit-ventricles. The brain parenchyma changes were observed as disorganized, with partially stripped-off ependymal lining, remarkable gliotic scar tissue in the subependymal areas and adjacent white matter, and widely opened Virchow-Robin spaces. These seem to be responsible for the decreased intracranial compliance and isolation of the CSF pathways.

Animals↗

[Incidence and characteristics of cerebrovascular disorders in children--critical analysis of 120 cases experienced at a children's general hospital].

Cerebrovascular disorders in children is a rare clinical entity, epidemiologic studies of which are very scarce in Japan. Hence this study analyzed 13,131 sick children admitted to Children's General Hospital in light of the incidence of cerebrovascular accident in children and its specific characteristics. In this paper, the cases of cerebral infarct are analyzed with special reference to their developmental outcomes. The results show that one hundred twenty children (0.85 percent of all sick children) had cerebrovascular disorders documented both in clinical pictures and CT scans. This number accounted for 2.5% of 4,738 CT examinations performed for these sick children. There were 79 cases of intracranial hemorrhage, 24 of cerebral infarction and 17 of vascular anomalies, 65.8%, 20.0% and 14.2% respectively. In the intracranial hemorrhage group, there was a different pathophysiology in each age group. The fact that intraventricular hemorrhage occurred in premature neonates, subarachnoid or posterior fossa subdural hemorrhage in mature neonates and infants, and intracerebral hematoma in elder children due to different causes was very striking. In the cerebral infarct group, the middle cerebral artery was most commonly affected (11 out of 24 cases); others had various lesions such as lacunar stroke, internal carotid artery occlusion and so on. The most impressive but disappointing fact in those children was that their clinical pictures were quite miserable, revealing low IQs. Nine out of 24 children with cerebral infarct had IQs below 20. In the abnormal vessels group, there were Moyamoya disease, arteriovenous malformation, intracranial aneurysm, Sturge-Weber syndrome, Menkes disease and coiling of the internal carotid or vertebral arteries each demonstrating unique angiographic findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗

[Early radical operation of trigonocephaly in infancy--pathophysiological concepts and operative procedure of premature closure of the metopic suture].

The radical operative procedure for premature closure of metopic suture (trigonocephaly) was theoretically discussed on the basis of the pathophysiological concepts analyzed by the CT measurement. The authors experienced with 7 cases of trigonocephaly of infancy during the last 3 years. CT measurement for the analysis of development of the anterior cranial fossa/the orbital roof, was made on these cases setting up the standard of nasiopterional angle (N-P angle), nasio-clinoid angle (N-C angle), bi-pterional distance (B-P distance) and nasio-clinoid distance (N-C distance). Random sampling was done for the normal value or control from 30 normal childrens' CTs. The results revealed the fact that trigonocephaly in infancy has more markedly acute in N-P angle and short in B-P distance for more severely deformed trigonocephaly, but was within normal limit in N-C distance with normally shaped fronto-nasal angle. The theoretical operative goal for the early radical reconstructive procedure in trigonocephaly was felt that the lateral and superior orbital burrs should be advanced with the nasion as the key point until obtaining normal N-P angle and B-P distance. By performing the above procedure with tight fixation of 1 cm square bone fragment on each side, a satisfactory expansion of the anterior cranial fossa could be obtained as a result. The prematurely closed metopic suture should be stripped off down to the nasion to correct hypotelorism.(ABSTRACT TRUNCATED AT 250 WORDS)

Cranial Sutures↗

Slit ventricles as a cause of isolated ventricles after shunting.

In a follow-up study of 164 hydrocephalic children without tumors treated with ventriculoperitoneal shunts, 46 (28.0%) developed slit ventricles, 5 (3.0%) developed isolated fourth ventricles, and 4 (2.4%) developed isolated unilateral hydrocephalus. All of the patients with isolated unilateral hydrocephalus and 3 with isolated fourth ventricles had associated slit ventricles, 2 of whom had enlarged ventricles as double-compartment hydrocephalus. Reopening of the foramen of Monro or the aqueduct was achieved in one of the former and two of the latter cases with re-expansion of the slit ventricles. It is suggested that in some cases, the slit ventricle could be a causative factor in post-shunt isolated ventricle.

Brain Diseases↗

Pathophysiology of nonneoplastic obstruction of the foramen of Monro and progressive unilateral hydrocephalus.

Our experience with progressive unilateral hydrocephalus in children and the pathophysiology of nonneoplastic obstruction of the foramen of Monro has been analyzed. The status of the foramen of Monro in either congenital or acquired progressive unilateral hydrocephalus was classified into the following four categories: Category 1, atresia of the foramen; Category 2, morphological obstruction; Category 3, functional obstruction; and Category 4, patent foramen. Illustrative cases including hydrodynamic studies and intracranial pressure monitoring are discussed.

Brain↗