Aneurysms carotid bifurcation

Kaech D, de Tribolet N, Lasjaunias P (1987) Anterior inferior cerebellar artery aneurysm, carotid bifurcation aneurysm, and dural arteriovenous malformation of the tentorium in the same patient. Neurosurgery 21 575-582... 

Atherosclerosis mainly affects large- and mediumsized arteries. Extracranial manifestations at the carotid bifurcation statistically dominate the intracranial arteries. Besides typical manifestations at the carotid siphon or the vertebrobasilar junction, atherosclerosis is occasionally also found in peripheral intracranial vessel segments. Typical sequelae of atherosclerosis are stenosing plaque formations, ulcerations, dilatations or the evolution of fusiform aneurysms, which can be accompanied by extensive formation of thrombus. 

Fig.5.6e-I. Various locations of aneurysms (continued), e Small basilar trunk aneurysm and aneurysm at the PI segment, f Basilar tip aneurysm, g Acorn aneurysm, h ICA aneurysm at the origin of the Pcom artery, so-called Pcom aneurysm, i Aneurysm at the bifurcation of the pericallosal and callosomarginal artery, so-called pericallosal aneurysm, j MCA bifurcation aneurysm, k ICA aneurysm at the origin of the ophthalmic artery, so-called paraophthalmic aneurysm. I Distal carotid bifurcation aneurysm...

Fig. 5.7. Seven years after clipping an Pcom aneurysm on the right side a de novo aneurysm at the distal carotid bifurcation was found on the left side, primarily seen on MRI performed because of headache...

Fig. 5.54a-c. Typical intracranial carotid bifurcation aneurysm. MRA 6 month after embolization revealed stable occlusion... 

Atherosclerotic vascular disease is more frequent in elderly patients and may be associated with more tortuous vessel anatomy. Superselective catheterizations of distal cerebral vessels might thus become technically more difficult. Atherosclerotic carotid bifurcation disease is frequently associated in patients with advanced age and might increase the risk of thromboembolic complications. In selected cases, a combined approach, first stenting of the carotid artery stenosis and subsequently coil embolization of the ruptured aneurysm might be a therapeutic option. 

Most arterial aneurysms arise at the bifurcation of major arteries, and this is also true for the intracranial location. Around 85% of all intracranial aneurysms originate from the anterior circulation. The most common location (30%-35%) is the anterior communicating artery (Acorn). However, many of these so-called Acorn aneurysms do have their origin at the A1/A2 junction of the anterior cerebral artery and do not involve the anterior communicating artery. Internal carotid and posterior communicating artery aneurysms account for 30% and middle cerebral artery (MCA) bifurcation aneurysms for 20%. Around 15% of intracranial aneurysms arise at the vertebrobasilar circulation. Half of them develop at the basilar tip (with various degrees of involvement of the PI segments) and the other 50% from other posterior fossa vessels. Aneurysms of the anterior inferior cerebellar artery (AICA) and vertebral artery (VA) aneurysms without involvement of the VA-PICA junction or the vertebrobasilar site are extremely rare. 

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