Experimental Hydrocephalus Produced by the Subarachnoid Infusion of Silicone Oil

VARIETY of techniques has been employed experimentally to produce hydrocephalus in adult and infant animals; many of the methods have been reviewed by Pudenz, et als Most successful was the injection of irritants such as India ink into the cisterna magna of rats 4 or kaolin into the subarachnoid space of dogs. 8 Hydrocephalus also occurs following the introduction of foreign bodies, such as cotton, into the aqueduct of Sylvius in adult dogs. -~ Trypan blue, when administered to pregnant rats, produces aqueductal stenosis and a high rate of hydrocephalus in the offspring? Tellurium in the diet 9 of pregnant rats and fetal infection with mumps virus 6 may also be followed by hydrocephalus in the newborn. The technique presented here for inducing hydrocephalus involves the infusion of inert silicone oils into the cisterna magna either indirectly through a polyethylene tube inserted into the spinal subarachnoid space, or by direct puncture of the posterior atlantooccipital membrane. Wisniewski 11 observed, in dogs, that intraventricular infusion of these oils cause little or no inflammatory reaction either of the ependymal surface or within the meninges, even when the contact was maintained for over 6 months. The bland nature of the oils and the distance of the injection site from the lateral ventricles eliminates the complications of mechanical damage and inflammation, thus allowing a more reliable interpretation of histological and physiological data.