Rupture After Bypass and Distal Occlusion of Giant Anterior Circulation Aneurysms

Giant aneurysms are very high-risk lesions both in terms of natural history and treatment. Bypass with distal occlusion is thought to be a safe treatment option for these aneurysms. Here, we report 2 cases of aneurysm rupture after bypass and distal occlusion, review the literature, and discuss the possible underlying mechanisms, in the hopes of influencing treatment planning and averting such complications in the future.

Two patients successfully underwent surgical treatment of a giant anterior circulation aneurysm via bypass and distal vessel occlusion. In each case, there was sudden thrombosis of the aneurysm without any sign of rupture at the time of surgery. Both patients then experienced delayed postoperative rupture with devastating consequences.

Aneurysm rupture can occur after bypass and distal occlusion, despite initial appearances of intraoperative stability. We suggest that the mechanisms are not a simple pressure within the dome and may be due to rapid thrombosis with subsequent aneurysm wall destabilization or stretching and capacitance causing persistent filling. When possible, it seems that complete trapping or proximal occlusion may be preferable to distal occlusion for these giant aneurysms. The optimal management of these highly morbid lesions remains to be determined.