Traumatic acute epidural hematoma caused by injury of the diploic channels

Traumatic acute epidural hematomas (EDHs) commonly develop by rupture of the meningeal arteries. EDH caused by an injury of the diploic channel (DC) has not been reported.

A 21-year-old man suffered a head injury while falling off the skateboard. At presentation, the patient was drowsy but did not exhibit any focal neurological deficits. Cranial computed tomography (CT) revealed a biconvex intracranial hematoma with 18-mm thickness in the high parietal region and a linear fracture that involved both the outer and inner tables and passed above the hematoma. A well-developed and large DC was observed near the hematoma. Patient's consciousness level decreased at 12 h after admission with considerable growth of the hematoma. A frontoparietal craniotomy revealed an EDH. The dura mater and the meningeal arteries underneath the hematoma were intact. The medial bone cut caused brisk bleeds from the large DC. Postoperative CT revealed the cut of the DC and other finer DCs exhibiting air density and lying near the fracture. Based on these findings, we assumed that the EDH was developed by an injury of the DCs.

Traumatic EDH can develop by an injury of the DCs. Careful observation of patient's neurological status and precise interpretation of neuroimages is important to identify venous EDHs.