Optic pathway infarct after Onyx HD 500 aneurysm embolization: visual pathway ischemia from superior hypophyseal artery occlusion.

We report a case of visual deterioration after Onyx HD 500 embolization of a left 7 mm superior hypophyseal artery (SHA) aneurysm. After the procedure, the patient experienced a right incongruous homonymous hemianopia, and MRI showed an infarct of the ipsilateral optic chiasm/tract but no evidence of aneurysm mass effect or embolic cortical infarcts. The optic pathway ischemia is believed to be secondary to Onyx penetration and occlusion of an SHA branch near the aneurysm neck. Caution is advised when using liquid embolic agents to treat SHA aneurysms as SHA occlusion may lead to visual deficits. [ABSTRACT FROM AUTHOR]