Abstract
A 70-year-old woman underwent emergency surgery for a ruptured aneurysm of the right middle cerebral artery. After neck ligation of the aneurysm, papaverine hydrochloride (40mg in 20ml of saline) was administered around the spastic portion of the peripheral middle cerebral artery. At the end of the surgery, hemimydriasis was observed without any other neural complication. Her pupils retured to normal size in 2 hours without visual disturbance. Local intracranial administration of an excessive amount of papaverine was considered to be the cause of transient mydriasis.
