[Postoperative epidural hematoma remote from the site of craniotomy for STA-MCA anastomosis]

We experienced a case in which the cause of acute brain swelling following resection of dura matter could not be recognized until the postoperative CT scan. A 30-year-old woman presented with a 4-year history of Moyamoya disease. Right hemiplegia developed a month before operation, so that the anti-platelet therapy was continued. At the end of dural resection the brain started to bulge and the brain swelling increased progressively. The patient was immediately placed on a head up position and received a rapid administration of mannitol for the treatment. The operator performed the echo examination for clarifying the cause of the brain swelling, but they could not find it. As the brain swelling slightly improved by the treatment, the surgery was performed continuously At the end of the operation the patient was moved for a CT scan and it showed mass effect caused by epidural hematoma over the left temporal region distant from the site of craniotomy. Evacuation of the hematoma was carried out urgently. At discharge, she was conscious and had no focal neurological deficits. The occurrence of the epidural hematoma is one of the reasons for unknown brain swelling during surgery. We strongly recommend that any sudden deterioration during the operation should be treated with emergency CT scan.