They generally are silent until they rupture and the rupture is associated with high morbidity and mortality.
Aneurysms require emergency treatment.
Occasionally, aneurysms are complex in shape and may be difficult to fully isolate from the arterial flow with a clip. On other occasions, there are small important arteries arising from behind the aneurysm, which may be included within a surgically placed clip. The endoscope can aid the surgeon in both instances by peering behind the aneurysm to see how fully the aneurysm has been clipped or to determine whether an artery has inappropriately been included within the clip. On rare occasions, it has been possible to perform the full aneurysm surgery using the endoscope.