Ruptured Intrameatal Aneurysm of the Anterior Inferior Cerebellar Artery Accompanying an Arteriovenous Malformation: a Case Report

Abstract

The distal anterior inferior cerebellar artery (AICA) aneurysms located inside the internal auditory canal are rare. The association of the distal AICA aneurysms and an arteriovenous malformation (AVM) on the same arterial trunk is exceptional. Eight reports of a total of ten cases have been published and all of the reported aneurysms were located in the meatal or postmeatal segment of the AICA. Herein, we report a case of ruptured aneurysm in the intrameatal portion of the AICA accompanying an AVM fed by the same artery. A 55-year-old man suffering from subarachnoid hemorrhage due to a ruptured intrameatal aneurysm with a small AVM underwent surgical trapping of the meatal loop, resulting in uneventful recovery. Follow-up angiography demonstrated neither aneurysm nor residual AVM nidus. We propose that trapping of the meatal loop could be a safe and feasible alternative to unroofing followed by neck clipping in selected patients with an intrameatal aneurysm of the AICA. We also review here the relevant literature.

Ruptured Total Intrameatal Anterior Inferior Cerebellar Artery Aneurysm

“…A possible explanation for this deficit may be nerve manipulation during surgery or internal auditory artery injury 9) . During the operation, we found that the aneurysm was tightly adhered to the nerves as described in other reports 6 9 10) . Therefore, during the dissection the eighth nerve was manipulated.…”

“…As for treatment, microsurgical direct clipping is considered to be the first line of treatment 6 10) . Endovascular treatment is not considered as the primary treatment because of difficulty in catheter navigation and the possibility of parent artery occlusion, but is used for elderly patients and those in poor general condition 7) .…”

Dissecting aneurysm of the anterior inferior cerebellar artery in the internal auditory canal presenting with deafness without hemorrhage: A case report and literature review

“…[10] To the best of our knowledge, intrameatal AICA aneurysm has been reported in only 26 patients (21 women), including our patient. [3,5,6,8,9,11,13,14,15,[17][18][19][20]22,25,29,32,33,35,37,38,40,41] e patients' ages ranged from 35 to 83 years, with a mean age of 61.3 ± 14.0 (standard deviation) and median age of 62 years. e comorbidities included hypertension in seven patients, dyslipidemia in four patients, and diabetes mellitus in three patients.…”

“…[4,10,26,29] However, an aneurysm in the internal auditory canal (IAC) is rare; only 25 cases have been reported thus far. [3,5,6,8,9,11,13,14,15,[17][18][19][20]22,25,29,32,33,35,37,38,40,41] It generally presents with subarachnoid hemorrhage (SAH). Herein, we have reported an extremely rare case of intrameatal aneurysm caused by dissection of the AICA, presenting initially with the eighth nerve palsy and then the seventh nerve palsy without SAH.…”

A Classification for the Anterior Inferior Cerebellar Artery—Subarcuate Artery Complex Based on the Embryological Development

“…circulation seem to contribute to the development of distal AICA aneurysms, 61,62 as well as high-flow situations, as vascularized tumors, 62,63 arteriovenous fistula, 64 and malformations. 65,66 Also, a case of ruptured aneurysm of a SAA feeding a dural arteriovenous fistula was reported. 64 Isolated AICA aneurysms have been interpreted in two major groups: pontine (proximal, premeatal) and cerebellar (distal, postmeatal) 67,68 ; parent vessel occlusion may lead to life-threatening consequences in the former group 68 ; therefore, these patients are candidates to arterial bypass.…”