Cerebral aneurysms causing visual symptoms: their features and surgical outcome

Cerebral aneurysms causing visual symptoms before surgery are relatively ra re. We have experience with 17 cases of such aneurysms and report their cli nical features and surgical outcome. The locations of aneurysms presenting with visual dysfunction in our series are as follows: internal carotid (IC) -cavernous aneurysms in six of 29 total cases, 21%; IC-ophthalmic aneurysms in nine of 36 total cases, 25%; and anterior communicating artery (A com A ) aneurysms in two of 217 total cases, 1%. The size of the aneurysms, the p eriod between the onset of symptoms and surgical treatment, the pre- and po st-operative visual function, and the surgical methods used to treat the an eurysm were analyzed. All the visually symptomatic cases featured large (15 -24 mm) or giant (> 25 mm) aneurysms. Visual symptoms occurred before aneur ysmal rupture in all cases but one. The type of visual field defect and the degree of reduced visual acuity were highly variable, without a typical cl inical presentation Five out of six IC-cavernous aneurysms were treated sur gically with common carotid artery (CC) ligation or IC ligation with superf icial temporal artery (STA) to middle cerebral artery (MCA) anastomosis. Th ree of these cases showed improvement of visual symptoms after surgery. Six out of nine IC-ophthalmic aneurysms were treated surgically (CC ligation o r direct clipping), with four cases showing improvement of Visual symptoms after surgery. One case of an A com A aneurysm featured a ruptured aneurysm that had physically penetrated the optic chiasm, while the other case was a giant unruptured aneurysm. The interval between the onset of symptoms and surgical treatment was the only factor identified which affected the clini cal outcome of the aneurysms presenting with visual dysfunction. All cases that were determined to show improvement of visual function were treated su rgically within 3 months of the onset of symptoms. Cerebral aneurysms prese nting with visual dysfunction before surgery are most commonly large or gia nt, and unruptured. Recovery of visual function can most often be expected when surgical treatment is performed expeditiously, before the visual dysfu nction becomes irreversible. (C) 1998 Elsevier Science B.V. All rights rese rved.