Newly Developed Aneurysm at the Anastomosis Site of a Superficial Temporal Artery to Middle Cerebral Artery Bypass Successfully Treated by Endovascular Embolization.

Abstract

The superficial temporal artery (STA) to middle cerebral artery (MCA) bypass is an effective treatment procedure for steno-occlusive severe ischemic disease of the anterior circulation. The formation of an aneurysm at the anastomosis site is a rare complication, and the mechanism underlying this condition and the appropriate treatment strategy, have not yet been established. We describe a case of an unruptured anastomosis aneurysm that was treated by endovascular embolization 7 years after bypass surgery. A 62-year-old woman presented with slurred speech, with magnetic resonance imaging and angiography showing multiple infarctions in her left cerebral hemisphere and severe stenosis in the left internal carotid artery and left MCA. An STA-MCA anastomosis was performed without neurologic sequelae. Five years later, follow-up magnetic resonance imaging showed that an aneurysm had formed at the MCA side of the anastomosis site. After 2 years, the saccular aneurysm had grown and was embedded in the brain parenchyma. Because the patient had experienced repeated problems with surgical wound healing, an endovascular intervention was performed, achieving obliteration of the aneurysm by coil embolization. Endovascular treatment is a feasible and efficacious treatment option for an aneurysm at the anastomosis site of an STA-MCA bypass.