Recanalization after endovascular occlusion of a dissecting aneurysm of the posterior cerebral artery--A case report and review of the literature.

Endovascular occlusion has been accepted as a safe, minimally invasive, and reliable treatment for ruptured dissecting aneurysms. Occlusion of the entire affected area is ideally the most complete treatment for such lesions. However, it is difficult to occlude the entire dissected lesion when it involves side branches due to the short-term risk of side branch occlusion, emboli dislodgement, and the long-term risk of parent artery recanalization. We herein present an extremely rare case where recanalization occurred after endovascular occlusion of a ruptured dissecting aneurysm of the posterior cerebral artery, and discuss its clinical implications. There are three mechanisms of recanalization: coil compaction due to loose or short segment packing, secondary dissection and occlusion of the false lumen. In endovascular occlusion of dissecting aneurysms that involve side branches, it is important to consider the risk of both recanalization and ischemic complications. We should attempt to insert the microcatheter into the true lumen and maintain dense packing as long as possible, unless the coils occlude the side branches following the procedure. Careful follow-up is necessary in all patients that received endovascular treatment.