OBJECT:The authors reviewed their 20-year experience with giant anterior communicating artery aneurysms to correlate aneurysm size with clinical presentation and to analyze treatment methods. METHODS:In 18 patients, visual and cognitive impairment were quantitated and clinical outcome was categorized according to the Rankin scale. Statistical analysis was performed using Fisher's exact test. CONCLUSIONS:At least 3.5 cm of aneurysm mass effect was required to produce dementia in the patient (p = 0.0004). Dementia was usually caused by direct brain compression by the aneurysm rather than by hydrocephalus. Optic apparatus compression occurred with smaller aneurysms (2.7-3.2 cm) when they pointed inferiorly. Aneurysm neck clipping was possible in half of the cases. Special techniques, including temporary clipping, evacuation of intraluminal thrombus, tandem and/or fenestrated clipping, and clip reconstruction were often required. Occlusion of or injury to the anterior cerebral artery (ACA) was the main cause of poor outcome or death. Proximal ACA occlusion, even of dominant A1 segments with small or no contralateral A1 artery, was an effective treatment alternative and was well tolerated as a result of excellent leptomeningeal collateral circulation.

Over the past 28 years, 39 patients with Moyamoya disease or syndrome defined as spontaneous occlusion of the circle of Willis with extensive basal collateral vessels have been treated by the author in Canada and the USA. All patients presented with clinical or radiologic evidence of hemorrhage (23) or ischemia and infarction (16). A total of 12 patients had associated cerebral aneurysms and seven of these patients with aneurysms presented with subarachnoid hemorrhage. The patients ages ranged from 5 to 47 years. Of these 58% were female. The patients racial origin included North American Indian, Innuit, East Indian/Pakistani, Japanese, Chinese, Filipino, Korean, Malayasian, Hispanic, African American and Caucasian. Familial clustering was seen in North American Indian, Innuit and Caucasian patients. Associated disorders (tuberculosis, pharyngitis, thalassemia, fibromuscular hyperplasia, polycystic kidney, sickle cell trait and hypertension) were common in these patients, as was the use of tobacco, alcohol and in the adult females, oral contraceptives. It may be concluded from this series that the etiology of Moyamoya disease or syndrome is probably multifactorial, but that some racial and familial groups are more susceptible. Furthermore, in that the clinical and angiographic features are identical, the separation between Moyamoya disease and syndrome may not be helpful in understanding the etiology and pathophysiology of this disorder.