Intraoperative development of contralateral epidural hematoma during evacuation of traumatic extraaxial hematoma

Intraoperative development of an epidural hematoma contralateral to a craniotomy for acute traumatic extraaxial hematoma has been previously reported. This entity, however, has never been distinctly defined and differentiated from either the delayed or the bilateral acute epidural hematoma. We present 3 new cases of intraoperative contralateral acute epidural hematoma and review the 14 previously reported cases. The typical clinical presentation is a severe head injury with an acute extraaxial hematoma and severe ipsilateral brain displacement during craniotomy. If brain displacement is not noted at craniotomy, then the contralateral hematoma is manifested by immediate postoperative neurological deterioration or intractable elevated intracranial pressure. The presence of any of these signs makes an immediate postoperative CT scan or burr holes contralateral to the original craniotomy mandatory for early diagnosis. In addition to defining "intraoperative contralateral epidural hematoma," stricter definitions of the terms "delayed epidural hematoma" (no hematoma present on the initial CT scan but one present on a later scan) and "bilateral epidural hematomas" (present on the initial scan) are proposed.