Distal anterior inferior cerebellar artery aneurysms

Abstract

Aneurysms of the distal anterior inferior cerebellar artery (AICA) are rare; fewer than 100 cases have been reported. The authors detail their experience with four cases and present endovascular as well as microsurgical management options. The medical records and neuroimaging studies obtained in four patients who were treated at a single institution were reviewed. Clinical presentations, neuroimaging and intraoperative findings, and clinical outcomes were analyzed. There were three men and one woman; their mean age was 43 years. Two patients presented with acute subarachnoid hemorrhage (SAH), and two presented with ataxia and vertigo (one with tinnitus, the other with hearing loss). Angiographic studies demonstrated aneurysms of the distal segment of the AICA. In one patient with von Hippel-Lindau syndrome and multiple cerebellar hemangioblastomas, a feeding artery aneurysm was found on a distal branch of the AICA. Three of the patients underwent successful surgical obliteration of their aneurysms, one by clipping, one by trapping, and one by resection along with the tumor. The fourth patient underwent coil embolization of the distal AICA and the aneurysm. All patients made an excellent neurological recovery. Patients with aneurysms in this location may present with typical features of an acute SAH or with symptoms referable to the cerebellopontine angle. Evaluation with computerized tomography, magnetic resonance (MR) imaging, MR angiography, and digital subtraction angiography should be performed. For lesions distal to branches coursing to the brainstem, trapping and aneurysm resection are viable options that do not require bypass. Endovascular obliteration is also a reasonable option, although the possibility of retrograde thrombosis of the AICA is a concern.

Management of anterior inferior cerebellar artery aneurysms: an illustrative case and review of literature

“…Incidences of peripheral AICA aneurysms on dorsolateral and caudomedial branches of the same vessel have been reported. 4 Zager and colleagues 63 have described a patient with a ruptured meatal loop aneurysm in whom 3 prior negative DS angiograms had shown no positive findings. Iwanga and associates 27 have described a peripheral aneurysm that was diagnosed on CT angiography but was previously undetected on 2 DS angiograms; the aneurysm eventually bled.…”

Occipital Artery-Anterior Inferior Cerebellar Artery Bypass With Microsurgical Trapping for Exclusively Intra-meatal Anterior Inferior Cerebellar Artery Aneurysm Manifesting as Subarachnoid Hemorrhage

“…Intra-meatal AICA aneurysms are extremely rare, with only 16 previous cases. [2][3][4][5][7][8][9][10]12,16,17,[19][20][21] Ten of these 16 patients were treated by microsurgical neck clipping 4,[8][9][10]17,[19][20][21] by opening the meatus with extensive nerve dissection, 5 patients underwent meatal loop trapping without bypass, 2,3,7,12,16) and one patient with unruptured aneurysm was managed by microsurgical packing of the internal auditory canal. 5) None of the 5 patients treated by simple meatal loop trapping developed cerebellar infarction, probably due to the favorable collateral blood supplies from dominant PICA and superior cerebellar artery.…”

“…[2][3][4][5][7][8][9][10]12,16,17,[19][20][21] Female prevalence (female/male＝15/1) is remarkable, with mean patient age of 53 years. Most patients (15/16) developed subarachnoid hemorrhage (SAH) at the onset, [2][3][4][7][8][9][10]12,16,17,[19][20][21] and only one presented with hearing disturbance due to the mass effect of the aneurysm. 5) The pathological nature of intra-meatal aneurysm is unclear.…”

Management of Anterior Inferior Cerebellar Artery Aneurysms: Endovascular Treatment and Clinical Outcome

“…To date, there have been reported only 17 AICA aneurysms treated by EVT, all of which were in the distal AICA and were treated by parent artery occlusion, except in 2 cases. [22][23][24][25]29,30,[40][41][42][43][44][45][46][47] The reasons for EVT in proximal AICA aneurysms may be as follows: 1) development of technologies regarding endovascular devices, 2) all treated aneurysms not fusiform but saccular, and 3) accessibility to anatomic configuration by an endovascular device. Because all the treated AICA aneurysms were saccular, it was possible to preserve the parent artery with endosaccular embolization, and stent-assisted coiling was also applied in cases of the wideneck AICA aneurysms.…”

“…The former can be treated by clip ligation at the neck, and the latter may be trapped or occluded surgically or endovascularly. 6,21,24,25,[29][30][31] The etiology of the AICA aneurysm is controversial: hemodynamic stress, embryonic vulnerability, flow-related vascular pathology, and arterial dissection by local trauma or nonspecific inflammation. 29,[32][33][34][35][36][37][38][39] Our study showed that 2 aneurysms were accompanied by AVMs and Moyamoya disease.…”