Acute subdural hematoma in patients who underwent aneurysm clipping--four case reports.

Four patients presented with intracranial hemorrhage mainly consisting of acute subdural hematoma (ASDH), who had all undergone aneurysm clipping 2-20 years earlier. Whether the clips had slipped or new trauma had caused the bleeding was difficult to determine, since the initial computed tomography showed that the subarachnoid hemorrhage or the intracerebral hematoma developed near the clips. Angiography in three patients showed that the clips had not slipped off. Three of four ASDHs appeared in the same side as the craniotomy used for the previous aneurysm surgery. Anti-platelet agents and ventriculoperitoneal shunting had been previously used in two patients with no causal signs of trauma. The outcomes were poor in three patients and one patient died. Weakening of the extra- or intracranial structure after aneurysm surgery might have been involved together with the postoperative anti-platelet agent and shunt treatment in the etiology of the present ASDH.