Biomedical subjects
Publications and source records attributed to F Epstein.
The authors have summarized their experience in the application of computerized axial tomography to the overall management of hydrocephalus.
A series of cats were made hydrocephalic by intracisternal injection of kaolin, and four weeks later ventriculography confirmed the presence of hydromyelia. Ten days later, laminectomy in the lower thoracic region was performed. Several days later ventriculography revealed a markedly dilated central canal beneath the entire laminectomy, and pathological examination confirmed the presence of a focal bulge confined to the same region. On sectioning, it was evident that the central canal was massively enlarged to fill the entire spinal cord beneath the bulging region. The conclusion from these findings is that myelomeningocele is the result of progressive intra-uterine disease which begins with pathological hydromyelia and culminates in rupture of the unsupported spinal cord as a result of maldevelopment of associated dermal tissue.
Computed tomography (CT) is a safe and reliable technique for the study of children with increased head circumference. Hydrocephalic children requiring drainage of cerebrospinal fluid may be shunted on the basis of the CT scan alone and their postsurgical course followed by serial CT scans thereafter. Any additional pneumographic studies required may be performed via the existing shunt tube, eliminating transcerebral catheterization and its attendant complications.
Computerized axial tomography (CAT) is a new, highly accurate technique for studying the skull and intracranial contents. It is rapid enough to be utilized in acute emergencies and safe enough to be utilized for routine serial followups and evaluation of outpatients with equivocal findings. Because CAT can delineate the ventricular system without need for contrast agent, can distinguish clearly between hematoma and edema and can differentiate cystic from solid tumors, it finds wide application in the evaluation of neurological disease.
Adult cats with hydrocephalus were sacrificed at varying times following valveless ventricular shunting. This shunting resulted in a prompt reduction of ventricular size and rapid gross reconstitution of cortical mantle. Ultrastructurally it was evident that white matter edema persisted for many weeks, even in the presence of normal size ventricles. The areas most severely affected by the hydrocephalus such as the corpus callosum showed a paucity of myelinated fibers and their replacement by numerous reactive astrocytes. Reconstitution of the cortical mantle consists predominantly of a diminution of white matter edema and reactive astrocytosis. Clinical improvement undoubtly results from the functional improvement of remaining elements rather than from the replacement of lost elements. This scheme of hydrocephalus suggests that if hydrocephalus is relieved when only ependymal disruption and periventricular water accumulation have occurred, it may be reversible. The subsequent sequence of events consisting of axonal degeneration, myelin disruption and reactive astrocytosis may be less, if at all reversible.
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The purpose of this study was to ascertain the sequence of events and the cellular constituents involved in reconstituting the cortical mantle after ventricular shunting. The subjects were severely hydrocephalic adult cats. After insertion of a shunt, the ventricular system rapidly returned to normal size and there was gross reconstitution of the cortical mantle. However, there still remained in the cortical mantle many of the histological changes seen before insertion of the shunt. The effect of hydrocephalus is mainly upon axons in the periventricular white matter. The axons become stretched and finally disrupted, resulting in disintegration of the surrounding myelin. In the absence of axons, remyelination cannot take place. It would seem, therefore, that prompt reversal of hydrocephalus is necessary in order to preserve the anatomical and functional integrity of the brain.
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36 patients with congenital hypertelorism, eight with Crouzon's disease, and three with a posttraumatic deformity, were operated with Tessier's technique with some modifications, i.e. the dura is not separated from the cribriform plate avoiding olfactory damage. The entire procedure for hypertelorism could be carried out in less than 5 h but correction of Crouzon's disease required 6-8 h, and longer in older patients. There was only one intraoperative anesthesic death in a 3-year-old child. One cardiac arrest recovered. Nine staphylococcus infections were superficial and readily treated. There was postoperative cerebral edema in one case and convulsions following surgery in another. Anticonvulsants and steroids were subsequently routinely employed. There were no SF fistulas. Excellent cosmetic results are due primarily to the skill of the plastic surgeons.
Cerebral blood flow was measured by the indicator fractionation technique in normal, acute hydrocephalic, chronic compensated hydrocephalic and craniectomized hydrocephalic cats. In the five normal cats the mean total brain blood flow was 136.1 ml/min/100 g dry weight. The six acute hydrocephalic animals demonstrated a relatively uniform 22% reduction in total blood flow. In eight chronic hydrocephalic cats CBF increased to the point where there was only an overall 7% decrease. In three hydrocephalic and craniectomized cats the CBF was reduced by 30.6%. In the acute phases there was a decrease in the number of blood vessels. Chronic compensated hydrocephalic brains had somewhat more vessels than the normal, whereas the craniectomized, massively hydrocephalic brain had a dramatic increase in both the number and caliber of blood vessels. These results clearly demonstrate that in acute obstructive hydrocephalus in cats, there is a significant decrease in CBF. The blood vessels revert to normal in shunted cats.
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