Aneurysm of the Distal Anterior Inferior Cerebellar Artery Unrelated to the Cerebellopontine Angle: Case Report

Abstract

This is a case report of an unusual aneurysm of the distal anterior inferior cerebellar artery. A 44-year-old woman had a severe frontal headache and vomiting of sudden onset. On the day after admission, the patient began to demonstrate nuchal rigidity and difficulty with upward gaze bilaterally. There were no complaints at this time suggestive of a syndrome of the cerebellopontine angle. A computed tomographic scan revealed an intraventricular hemorrhage of the 3rd and 4th ventricles; however, multiple attempts at four-vessel angiography were required before an aneurysm could be demon-strated. On the 28th hospital day, a suboccipital craniectomy using the retromastoid approach in the lateral position was performed. A saccular aneurysm with a surrounding hematoma in the distal anterior inferior cerebellar artery was found and clipped. The operative findings revealed that the aneurysm was unrelated to the cerebellopontine angle. After surgery, the patient had an uneventful recovery and complete resolution of symptoms.

Subarachnoid Hemorrhage Caused by Rupture of a Distal Anterior Inferior Cerebellar Artery Aneurysm -Three Case Reports-

“…6,9,13,14,17) The AICA is a branch of the basilar artery and courses inferolaterally toward the cerebellopontine angle, crosses the abducens nerve at the angle and the cerebellar flocculus between the facial and acoustic nerves. The meatal loop is located anterior to the flocculus and posterior to the auditory canal.…”

“…Aneurysms in the AICA are 2.5 times more common in females than in males, and from 17 to 81 years old (mean 48.2 years old). 8,11,[13][14][15]17) Only 84 cases of distal AICA aneurysm have been reported, and the distal AICA is the least likely intracranial main arterial trunk to harbor an aneurysm. 8,11,[13][14][15]17) Ruptured AICA aneurysms manifested as acute onset of subarachnoid hemorrhage (SAH) in 67% of cases, associated with sudden severe headache, meningismus, nausea, vomiting, photophobia, and sudden coma.…”

“…8,11,[13][14][15]17) Only 84 cases of distal AICA aneurysm have been reported, and the distal AICA is the least likely intracranial main arterial trunk to harbor an aneurysm. 8,11,[13][14][15]17) Ruptured AICA aneurysms manifested as acute onset of subarachnoid hemorrhage (SAH) in 67% of cases, associated with sudden severe headache, meningismus, nausea, vomiting, photophobia, and sudden coma. 8,11,[13][14][15]17) Another 20% of cases manifested as cerebellopontine angle syndrome, which consists of tinnitus, hearing loss, vertigo, facial paresis, gait ataxia, dysmetria, diplopia, and facial sensory disturbance, in patients with large aneurysms as a result of a mass effect rather than of hemorrhage.…”

“…8,11,[13][14][15]17) Ruptured AICA aneurysms manifested as acute onset of subarachnoid hemorrhage (SAH) in 67% of cases, associated with sudden severe headache, meningismus, nausea, vomiting, photophobia, and sudden coma. 8,11,[13][14][15]17) Another 20% of cases manifested as cerebellopontine angle syndrome, which consists of tinnitus, hearing loss, vertigo, facial paresis, gait ataxia, dysmetria, diplopia, and facial sensory disturbance, in patients with large aneurysms as a result of a mass effect rather than of hemorrhage. 15,17) These symptoms result from compression of cranial nerves or the brainstem, and may be prodromal signs of rupture.…”

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

“…[9][10][11][12][13][14][15][16][17][18][19][20][21] Although various surgical approaches have been introduced to access these aneurysms, surgical treatment is often limited due to the complexity of the adjacent neurovascular structure, the presence of brain stem perforators, the narrow and deep surgical field, and the necessity of an experienced surgeon.…”