Bilateral symptomatic large cavernous carotid artery aneurysms treated by extracranial-intracranial bypass with parent artery occlusion

Bilateral large cavernous sinus internal carotid aneurysms (CCAs) occur very rarely. While the choice of treat-ment method is important, the timing of contralateral side treatment is equally important. We herein report the case of a 72-year-old woman who presented with progressive bilateral visual impairment and was treated by two -stage. First, the left CCAs had been treated, and the aneurysm was thrombosed, but her left visual acuity did not recover; the right CCA was becoming larger 2 years later, and her right visual acuity began worsening. The right CCAs was treated by almost same method. Her right visual acuity improved compared with the second preop-erative findings. Our case findings suggest the importance of considering the appropriate timing to avoid symptom aggravation in patients with bilateral CCAs.