[A case of traumatic dissecting aneurysm of the C1-2 portion of the internal carotid artery].

The authors report a case of traumatic dissecting aneurysm of the C1-2 portion of the internal carotid artery (ICA) in a 54-year-old woman. She suffered from traumatic SAH due to closed head trauma as a result of a motor vehicle accident. Twenty-five days after this accident, traumatic dissecting aneurysm of the C1-2 portion of the ICA that was caused by closed head trauma was ruptured and increased in size, as revealed by serial angiographic studies. In intraoperative finding, dissection involved the entire circumference of the C1-2 portion of the ICA. Clipping procedures were impossible, so internal carotid ligation and STA-MCA anastomosis was performed. To our knowledge, this traumatic dissecting aneurysm of the C1-2 portion of the ICA was the first case that presented with SAH. We discussed the mechanism of dissection of the ICA and operative strategy suitable for this aneurysm.