Traumatic Middle Meningeal Artery Aneurysm: A Rare Cause of Recurrent Acute Epidural Hematoma. A Case Report

Traumatic middle meningeal artery aneurysm (TMMA) is a rare condition and a known cause of several different bleeding patterns after head injury. Once detected, they need to be treated as an emergency due to their potential for morbidity and mortality. Generally, recurrence does not occur in surgery for acute epidural hematoma if adequate hemostasis is achieved. Here, we report a case of atypical postoperative recurrence of an acute epidural hematoma, possibly due to the development and rupture of a TMMA. A 41-year-old man with left acute epidural hematoma after a head injury was referred to our hospital. Emergency craniotomy was performed immediately, and the hematoma was removed. The source of the bleeding was near the fracture site in the middle cranial fossa, and sufficient hemostasis was confirmed. However, a head computed tomography (CT) scan the next day revealed a recurrence of the acute epidural hematoma. Magnetic resonance (MR) angiogram showed an aneurysm with a diameter of approximately 4 mm in the left middle meningeal artery. The recurrence of the acute epidural hematoma appeared to be related to the formation and a rupture of a middle meningeal artery aneurysm, and to prevent subsequent rebleeding, the patient underwent reoperation, and the hematoma and aneurysm were removed. In surgery for acute epidural hematoma, recurrence can be prevented by removing the hematoma and ensuring hemostasis. Although conventional surgery was performed in this case, a repeat of epidural hematoma occurred. A postoperative middle meningeal artery aneurysm had been thought to have developed, ruptured, and caused a repeat epidural hematoma. In treating acute epidural hematoma, a TMMA development should be considered when an atypical clinical course occurs, such as a recurrence of postoperative bleeding.