1997 Volume 25 Issue 6 Pages 423-427
We reviewed 12 cases of anterior wall aneurysms of internal carotid artery. We classified those aneurysms into two types as follows: 1) “chimame” (blister) type, which has a thin wall and fragile neck; and 2) “non-chimame” type, which has a usual wall and neck. Six cases had “chimame” type aneurysms. All 6 patients were women, ranging in age from 37 to 61 years (mean, 49 years). All aneurysms were the source of subarachnoid hemorrhage (SAH). The size of the aneurysms varied from 1 to 4mm with a mean of 2.8mm. There were also 6 cases with “non-chimame” type aneurysms. Three patients were men and 3 were women, ranging in age from 47 to 68 years (mean, 56 years). Two aneurysms were the source of SAH. The size of aneurysms varied from 5 to 18mm with a mean of 12mm. Intraoperative rupture occurred in 5 of the 6 “chimame” type aneurysms, and in only one of the 6 “non-chimame” type aneurysms. Neck clipping was done in one of the 6 “chimame” type aneurysms, but was done in all of the “non-chimame” type aneurysms. One patient of “chimame” type aneurysm treated by trapping died, but the others had good recovery.
“Chimame” type anterior wall aneurysm is easy to rupture, difficult to clip, and so necessitates special surgical techniques such as wrapping or trapping with bypass. On the other hand, “non-chimame” type anterior wall aneurysm can be clipped relatively safely. However, it is important not to induce intraoperative rupture during dissection and clipping, because the aneurysm is severely adherent to the frontal lobe or temporal lobe.
