[A case of A3-A3 bypass and proximal clipping for a ruptured left A1 dissecting aneurysm].

A 58-year-old woman was admitted to our hospital with sudden onset of headache. CT and angiogram revealed subarachnoid hemorrhage due to a dissecting aneurysm at the left A1 segment. ACoA was not identified. We performed proximal clipping with A3-A3 bypass for preventing the recurrence of the hemorrhage and for reducing ischemia in the territory of the left ACA. After the operation, CT revealed the infarctions in the corpus callosum, the left medial frontal lobe and the genu of the internal capsule. But the postoperative angiogram demonstrated no aneurysm and the opacification of the recurrent artery of Heubner and the part of perforating branches. A3-A3 bypass was patent. The patient experienced a good recovery without recurrence of bleeding.