With an incidence rate of 3.2 - 4.9 %1, unruptured intracranial aneurysms are common, especially in women over the age of 502. However, most aneurysms are detected incidentally as they are often asymptomatic. In this case which presented at Jikei University, Japan, the vertebral artery aneurysm compressed adjacent brain structures and the 74-year-old female patient therefore presented with left hemiparesis.
The decision regarding vertebral artery aneurysm treatment management is difficult, as treatment has a high rate of success, there is an inherent risk of complications, and nonoperative treatment comes with the risk of rupture. In this case the decision was made to watch and wait with operative treatment given the location of the aneurysm and its complex access, the fairly mild symptoms, and the aneurysm size of 27 mm (three dimensions: 27 x 21 x 24 mm).
Unfortunately, 4 months later the symptoms worsened, and MRI imaging revealed a giant partially thrombosed aneurysm of the right vertebral artery with perifocal edema as well as a large mass effect.
"The literature reveals that aneurysmal growth tends to occur more with larger aneurysms. The likelihood of aneurysms of 12 mm growing is 12 times higher than with 8 mm aneurysms."