Computed tomography of posterior fossa trauma.

A group of 1,700 cases of head trauma were reviewed to determine the incidence of posterior fossa injuries and to assess the value of computed tomography (CT) in their diagnosis and management. In 57 cases (3.3%), the most significant and primary injuries were within the posterior fossa. These included epidural hematoma (EDH), acute and chronic subdural hematoma (SDH), and parenchymal hemorrhage and contusion of the cerebellum and brainstem. The prognosis varies with the location and severity of the injury. Brainstem injuries are associated with a high mortality rate. Computed tomography proves particularly useful in the early recognition of brainstem injury. The demonstration by CT of obliteration of the cisterns surrounding the brainstem is a reliable sign of a grave prognosis in brainstem injury. Contrast enhancement is useful in demonstrating whether the dural sinuses are displaced, thus differentiating EDH from SDH. Except in the rare case of vascular injury unassociated with EDH, CT correlated with the neurological examination is an accurate method of determining the nature, location, and extent of significant posterior fossa injury. Scans of high quality are mandatory, and frequent supplementary contrast studies are recommended.