Congenital hydrocephalus: a new experimental model with histopathological study.
ABSTRACT We describe a new experimental model of fetal hydrocephalus in the lamb. 14 sheep were operated on at 100-120 days gestation for the insertion of a catheter into the fetal aqueduct of Sylvius to block cerebrospinal fluid (CSF) flow. After the operation the intracranial pressure (ICP) was measured daily from the distal end of the catheter. The progress of ventricular dilatation was recorded by ultrasound. At ICP 100 mm/H2O the animals were killed for postmortem examination of the fetuses. Neuropathological examination showed massive dilatation of the ventricles. The ependymal cells appeared to be flat and the cellular lining disrupted. Growth of pseudocysts, cellular stratification and proliferation of the paraventricular germinal cells were observed also. With our new experimental model we were able to control the rise in ICP and correlate the evolution of the anatomical damage with the duration of high ICP and with the gestational age at which it began. Our model can also be used at early stages of gestation for reversing the development of hydrocephalus. It might therefore provide information on the suitability of fetal hydrocephalus surgery.
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ABSTRACT: There are compelling physiologic arguments for correcting certain malformations before birth. Although fetal surgery has been successful in sheep and lower animals, it has proven difficult in primates because the gravid uterus is exquisitely sensitive to induction of preterm labor and abortion. Because the feasibility of fetal intervention can be determined only in a primate model, we have investigated the variables affecting fetal-neonatal survival after fetal surgery in 25 monkeys. As we improved our anesthetic and surgical techniques and refined our tocolytic therapy, mortality fell from 73.3% (11/15) to 20% (2/10). Since spontaneous perinatal loss in 56 controls was 21.4% we can now operate on the late second and early third trimester fetal monkey without increasing maternal or fetal-neonatal mortality. Success in this rigorous model is a requisite for attempted correction of human malformations in utero.Journal of Pediatric Surgery 05/1982; 17(2):115-22. · 1.38 Impact Factor
Article: Fetal surgery in utero.Texas medicine 10/1984; 80(9):40-8.
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ABSTRACT: An experimental model of kaolin-induced hydrocephalus in the dog was studied in order to evaluate the progress of ventricular dilatation and the communications between the ventricular system and the subarachnoid space. Skull and spine radiological studies were obtained after metrizamide intraventricular injection, and the baseline ventricular pressure and cerebral pulse pressure amplitude were measured in anesthetized animals. Intracranial compliance and resistance to drainage of cerebrospinal fluid were calculated by means of bolus injection test. Light and scanning electron microscope studies were done at different developmental stages of hydrocephalus. With these experimental parameters, two successive phases were seen: an initial acute hypertensive hydrocephalus (H1) with high resistance, low compliance, severe ependymal damage, and subependymal edema; and a late chronic normotensive hydrocephalus (H2) with little resistance increase, normal compliance, epithelial regeneration, and subependymal gliosis. Both the H1 and H2 stages showed an increase in the cerebral pulse pressure amplitude.Journal of Neurosurgery 12/1984; 61(5):918-24. · 3.15 Impact Factor