Aneurysms of the posterior inferior cerebellar artery

Abstract

The clinical and anatomical features of 21 surgically treated saccular aneurysms of the posterior inferior cerebellar artery (PICA) are analyzed. Seventeen of these lesions originated from the PICA-vertebral junction, and four arose from distal PICA branching sites. Twelve lesions arose from the left PICA, nine were right-sided, and all were small (less than 12.5 mm). Most of these aneurysms occurred in females (16 of 21) and presented as classic subarachnoid hemorrhage. The lack of specific focal deficits prevented an accurate pre-angiographic determination of aneurysm location in most instances. Clinically significant vasospasm and aneurysm multiplicity occurred with approximately equal frequency as at other locations. The angiographic and surgical features of these lesions are determined by the course of the vertebral artery and PICA; that is, they occur at branching sites and at curves in the parent vessel, and point in the direction in which flow would have continued if the curve at the aneurysm's origin had not been present. Aneurysms at the PICA-vertebral junction usualthese lesions are determined by the course of the vertebral artery and PICA; that is, they occur at branching sites and at curves in the parent vessel, and point in the direction in which flow would have continued if the curve at the aneurysm's origin had not been present. Aneurysms at the PICA-vertebral junction usualthese lesions are determined by the course of the vertebral artery and PICA; that is, they occur at branching sites and at curves in the parent vessel, and point in the direction in which flow would have continued if the curve at the aneurysm's origin had not been present. Aneurysms at the PICA-vertebral junction usually occur at least 1 cm above the foramen magnum level, arise distal to the PICA origin in the angle between the two vessels, and are best approached by a paramedian incision with the patient in the lateral recumbent position. Isolated clipping of the aneurysm neck is essential in this instance, as trapping may compromise vital perforating arteries of the brain stem. More distal (retromedullary) PICA aneurysms are sometimes associated with another vascular anomaly (two cases in this series), and are best handled through a bilateral suboccipital craniectomy. Clipping of the neck is the preferred treatment, but trapping is usually safe, if necessary.

Predicting Factors Affecting Clinical Outcomes for Saccular Aneurysms of Posterior Inferior Cerebellar Artery with Subarachnoid Hemorrhage

“…In view of location, posterior inferior cerebellar artery (PICA) aneurysms are reported to most frequently occur in the region where PICA originates in the vertebral artery (VA) 8,12) . When surgical clipping is performed, there are some risks of neurological complications because of the intimate anatomical relationships of the proximal PICA to the brain stem and lower cranial nerves 2,4,11) .…”

Distal posterior inferior cerebellar artery aneurysm: case report

“…The great majority of these aneurysms are located at the junction of the VA-PICA. In a clinical-anatomical study of 21 PICA aneurysms, only four arouse from distal PICA branches 3 . In Yasargil series, from 15 aneurysms of PICA, 10 were originated from the origin of the vessel 12 ; Salcman analyzed 13 aneurysms, 10 of witch arose from the junction of VA-PICA 2 .…”

“…The pathogenesis of aneurysms in PICA is matter of discussion. It is well accepted that the site of prediction of general aneurysms are the arterial bifurcations; however, the great majority of aneurysms at the distal PICA are not related to its branches [3][4][5][6] . Hemodynamic stress at the hairpin curve of the PICA may play a role in branchless aneurysm formation 7 .…”

“…The majority of them are localized at the vertebral artery (VA) PI-CA junction [3][4][5] . There are few large series of distal PICA aneurysms [6][7] , with no more than 26 cases.…”

"Infra-Posterior Inferior Cerebellar Artery Aneurysm" Arising After Occlusion of the Ipsilateral Vertebral Artery. Case Report.

“…The features of VA-PICA aneurysms are determined by the direction in which the parent artery would have continued, in common with most saccular aneurysms. 5) Anatomically, a saccular aneurysm, in contrast to a dissecting aneurysm, projecting proximally at the VA-PICA junction is very rare. 8) No such saccular aneurysm was found in a large series of more than 80 cases of VA-PICA aneurysms.…”