Traumatic extradural hematomas with delayed development.

After introduction of computerized tomography (CT), we experienced 74 patients with 78 traumatic extradural hematomas. Among these, 16 hematomas were subjected to sequential CT examinations in the early stage after injury. Four hematomas of four patients became enlarged, and another five hematomas of four patients were delayed. Accordingly the delayed extradural hematomas are thought to be less uncommon than previously believed. Three patients with four delayed extradural hematomas of surgical significance are reported, and pathogenesis of the delayed extradural hematoma is discussed.