Kunihiko Osaka

Development of the Cerebrospinal Fluid Pathway in the Normal and Abnormal Human Embryos

The subarachnoid space, the chorioid plexus and the arachnoid villi are microscopically studied in 60 normal human embryos and in 3 abnormal human embryos with rhombencephaloschisis and cervical myeloschisis. The subarachnoid space has been generally considered to be developed by outflow of cerebrospinal fluid (CSF) of the choroid-plexus origin from the IVth ventricle. This generally accepted concept does not meet with our findings: (1) cavity formation in the meninx primitiva is seen before appearance of the choroid plexus; (2) the primitive subarachnoid space is developed earlier in the prepontine region than in the area dorsal to the rhombic roof, and (3) the primitive subarachnoid space is formed in the embryos with dysraphism where the perineural subarachnoid space is separated from the ventricles. Apparently the embryonic pattern of CSF circulation should be much different from the generally believed pattern of adult, since the arachnoid villi are absent in the embryos and the ability of production of CSF in the embryonic choroid plexus is questionable. It is suggested that such embryonic pattern of CSF production and absorption may partly persist in adult human being.

Results of Treatment for Craniopharyngioma

A review of the results of treatment for 155 cases of craniopharyngioma during the past 47 years by the palliative operation was made. Steroid and operative microscope reduced operative mortality and gave more chance of total extirpation, but survival rate was almost unchanged. It is noteworthy that 3 cases who underwent palliative operation more than 30 years ago are still alive and leading useful lives. The quality of survival was somewhat less favorable in pediatric than adult cases. Morbidity frequently encountered in pediatric cases was growth retardaton. Craniopharyngioma is a benign tumor pathohistologically, but it should be considered as malignant because of the region it occurs in. Therefore, no forceful attempt to total extirpation should be made and the operations should, as a rule, be palliative.

Traumatic intrathoracic meningocele (traumatic subarachnoid-pleural fistula)

Abstract A case of thoracic meningocele induced by trauma (traumatic subarachnoid-pleural fistula) is reported, and the role of trauma in development of thoracic meningocele is discussed.

Craniopharyngiomas with unusual topography and associated with vascular pathology

SummaryOut of 155 cases of craniopharyngioma seen in the past 47 years, 19 are considered unusual. These 19 cases have been placed under the following headings— 1. unusual topography, and 2. associated vascular pathology. Since CT scanning offers important information about extension of craniopharyngiomas, it is very helpful for planning operative approach. However, cerebral angiography is still important for demonstrating vascular pathology.

Myeloschisis in early human embryos.

Four early human embryos with open myeloschisis are reported. These are a thoracolumbar myeloschisis in Carnegie developmental stage 12, a cervical myeloschisis in stage 13, and two lumbosacral myeloschisis in stage 14. All of them are the smallest human embryos with this type of malformation ever reported. In these embryos, the neuroectodermal junction is smooth and there is no microscopic evidence that the neural tube is forced open after its proper closure. The presence of the lesion in such early embryos, especially in one of stage 12, implies that the lesion evolved from the neural plate which never closed. Cellular polarity and the limiting membrane in the lesion are generally well preserved in spite of apparent overgrowth of the neural tissue. These findings do not support the hypothesis of LEMIRE et al. that the defective external limiting membrane predisposes to a loss of cellular polarity and resultant neural overgrowth.

Subarachnoid Erythrocytes and Their Contribution to Cerebral Vasospasm

Erythrocytes are not present in normal cerebrospinal fluid (CSF), and their presence there implies subarachnoid hemorrhage. The differential diagnosis of subarachnoid hemorrhage includes ruptured aneurysms or arteriovenous malformations, hypertensive cerebral hemorrhage, head trauma, and meningitis. Although erythrocytes are commonly found in the CSF of patients with vascular pathology, their clinical importance may not be well appreciated.