Transsphenoidal injection of silicone for the production of communicating or obstructive hydrocephalus in dogs.

A technique for the insertion of a spinal needle through the soft palate and sphenoid bone into the suprasellar cistern of dogs is described. Instillation of room-temperature-curing silastic elastomer via the needle causes an increased resistance to the flow of cerebrospinal fluid in the basal subarachnoid spaces above the tentorium, for the production of communicating hydrocephalus. If the needle is advanced farther, the same material can be injected directly into the third ventricle for the production of obstructive hydrocephalus. Twenty-five of 34 dogs (74%) developed hydrocephalus and survived to undergo subsequent experimentation.