Development of less invasive imaging studies, such as magnetic resonance angiography, has increased the chances that unruptured cerebral aneurysms are found. The rupture risk of “symptomatic” aneurysms is higher than for “asymptomatic” aneurysms; so “symptomatic” aneurysms are more often surgically treated. Many reviews examine “asymptomatic” unruptured cerebral aneurysms, but few evaluate “symptomatic” aneurysms. The author has treated many patients with symptomatic unruptured cerebral aneurysms and found that improved cranial nerve signs can be expected if the surgical treatment is performed before the symptoms become irreversible; the critical period is approximately 3 months. It is important to suppress the pulsation of the aneurysms compressing the cranial nerves; both a clipping procedure and endovascular coiling are effective. Cranial nerve signs are more commonly the symptoms of unruptured cerebral aneurysms, but large to giant aneurysms can also be the causes of hemiparesis, hydrocephalus, epilepsy, or even cerebral infarction. This review summarizes the features and surgical outcome of symptomatic unruptured cerebral aneurysms.
2010 by The Japan Neurosurgical Society