Long-lasting narrowing of the parent artery after bilateral clipping of mirror-image aneurysms of distal anterior cerebral arteries: a case report.

Because multiple intracranial aneurysms are not rare, accurate preoperative detection of asymptomatic aneurysms is important. In this paper, we report a ruptured distal anterior cerebral artery (DACA) aneurysm associated with an unruptured mirror-image aneurysm in a 62-year-old man presenting with headache. Although delayed vasospasm after subarachnoid hemorrhage has been reported to persist for 2 to 3 weeks, angiographic parent artery narrowing was far more prolonged in our case. Computed tomography revealed a subarachnoid hemorrhage in the interhemispheric and right sylvian fissures and a right frontal lobe hematoma. Digital subtraction angiography demonstrated bilateral symmetric saccular aneurysms of DACAs. On the day of admission, both aneurysms were clipped using an interhemispheric approach in a one-stage procedure, and the hematoma was aspirated. Angiography performed 8 days after the surgery demonstrated a residual aneurysm neck on the left side. Follow-up digital subtraction angiography performed on day 42 from onset showed resolution of the residual aneurysm neck along with narrowing of the left A2. However, at 7 months, the A2 narrowing had lessened. The location of the bilateral aneurysms near the midline facilitated a single approach but necessitated the application of juxtaposed clips. Regarding the pathogenesis of the bilateral aneurysms, previous reports have suggested symmetry of congenital anatomic defects and hemodynamic stress as potential causes. The persistent narrowing that was observed could have resulted from proliferative vasculopathy or from fibrosis possibly induced by the clips.