Abstract
In an attempt to define the tissue of origin of substances causing aseptic meningitis and secondary hydrocephalus after posterior fossa surgery, analysis of several marker substances from blood, brain, tumour and muscle in the CSF was performed early in seven postoperative patients. No clear pattern emerged which could relate the substances, CSF reaction, and meningeal scarring. The effects of various factors such as contrast studies, drainage, and steroids were also not clear. Review of the literature reveals that all four tissues can cause inflammation. Certain facts about the anatomy of the basilar cisterns and arachnoid villi probably make them logical sites for problems in CFS circulation. Children, for several reasons, are most susceptible to this complication. The complexity of factors in human cases suggests that the problem should be studied in an animal model.