Abstract
The dorsal internal carotid artery (ICA) aneurysm is a saccular aneurysm with a wide or semifusiform neck and often its wall and surrounding arterial wall are very fragile.
The authors describe details of the operative features of four illustrative cases of dorsal ICA aneurysm. The following are some technical points useful for safe and complete clipping:
1. It is desirable that the aneurysm dome has been dissected and exposed completely before applying a clip so that the clip can be placed parallel to the parent artery and also pressed against the artery to include the thin portion of the surrounding arterial wall in the brades. 2. In order to avoid premature rupture during the approach to the aneurysm, unroofing the optic canal and removing the anterior clinoid process are often helpful to secure the proximal parent artery for temporary occlusion; exposure of the ICA in the neck may be advisable when the aneurysm is located proximally. 3. Subpial dissection of the dome is useful especially when the aneurysm is buried in the brain or tightly adherent with the arachnoid membrane. 4. The aneurysm can grow in various directions from the dorsum of the ICA. The most difficult case for clipping is one in which the aneurysm protrudes toward the inner side of the curve of the parent artery, because parallel clipping without leaving a residual neck is difficult. In such cases, one needs to have various options including the above techniques as well as wrapping.
