Arachnoiditis from experimental myelography with aqueous contrast media.

Myelography was performed on 80 monkeys to study postmyelographic arachnoiditis. Metrizamide myelography caused arachnoiditis when high concentrations were used, but not with the usual clinical concentrations. Arachnoiditis resulted after myelography with meglumine iocarmate; however, the risk of arachnoiditis was reduced by diluting the contrast medium. Prophylactic intrathecal methylprednisolone was not effective in preventing arachnoiditis. Blood in the cerebrospinal fluid did not affect the degree of arachnoiditis.