Pontomedullary rent. A specific type of primary brainstem traumatic injury.

Pontomedullary rent is a primary injury to the brainstem that may occur in high-speed accidents. We present a series of 13 autopsies with complete or partial pontomedullary rent documented over a 12-year period. Of the 13 cases, seven had associated basal skull fractures and three had fractures of the cervical spine. In five patients, the rent was an isolated traumatic lesion of the brain. While pontomedullary rents are mostly caused by traumatic craniocervical hyperextension, some authors feel that these rents could be a form of diffuse axonal injury caused by angular acceleration of the head. In this study, two patients had documented features of diffuse axonal injury. More than one mechanism of injury could therefore be involved. Pontomedullary rents could be underdiagnosed, as partial rent is compatible with survival and, when there are no associated fractures, these tears may be attributed to artifactual damage occurring during removal of the brain at autopsy.