Spontaneous resolution of ruptured dissecting anterior inferior cerebellar artery aneurysm: A rare case report

Anterior inferior cerebellar artery (AICA) aneurysms: a radiological study of 15 consecutive patients

Introduction

The aneurysms of the anterior inferior cerebellar artery (AICA) are rare lesions of the posterior circulation and to treat them is challenging. We aim to present anatomical and morphological characteristics of AICA aneurysms in a series of 15 patients.

Method

The DSA and CT angiography images of AICA aneurysms in 15 consecutive patients were analyzed retrospectively. Different anatomical characteristics were quantified, including morphology, location, width, neck width, length, bottleneck factor, and aspect ratio.

Results

Eighty percent of the patients were females. The age was 52.4 ± 9.6 (mean ± SD) years. 11 patients were smokers. Ten patients had a saccular aneurysm and five patients had a fusiform aneurysm. Aneurysm in 10 patients were located in the proximal segment, in three patients in the meatal segment, and in two patients in the distal segment. Ten out of 15 patients presented with a ruptured aneurysm. The size of AICA aneurysms was 14.8 ± 18.9 mm (mean ± SD). The aspect ratio was 0.92 ± 0.47 (mean ± SD) and bottleneck factor was 1.66 ± 1.65 (mean ± SD).

Conclusion

AICA aneurysms are rare lesions of posterior circulation predominantly found in females, present predominantly with subarachnoid hemorrhage, and are mostly large in size.

Treatment and Outcome of Anterior Inferior Cerebellar Artery (AICA) Aneurysms: Helsinki Series of 15 Consecutive Patients

Objective Anterior inferior cerebellar artery (AICA) aneurysms are rare posterior circulation lesions that are challenging to treat. This article presents the treatment and clinical outcome of AICA aneurysms in an unselected cohort of patients.

Methods A retrospective analysis of patient record files, digital subtraction angiography, and computed tomography angiography images of 15 consecutive patients harboring AICA aneurysms treated between 1968 and 2017.

Results Of the 15 AICA aneurysm patients reviewed, 12 (80%) were females. Twenty percent had intracerebral hemorrhage and 40% presented with intraventricular hemorrhage. Eleven out of 15 (73%) patients presented with subarachnoid hemorrhage (SAH); 82% of SAH patients had a good-grade SAH (Hunt and Hess grade 1–3). Eleven patients (73%) were treated surgically, three (20%) were treated conservatively, and one (7%) had coil embolization. In 27% of patients, a subtemporal approach with anterior petrosectomy was performed. A retrosigmoid approach was used in the remaining 73%. In 18% of the patients, a parent vessel occlusion was necessary to occlude the aneurysm. Five out of 11 (47%) of the patients developed postoperative cranial nerve deficits. Twenty-seven percent developed shunt-dependent hydrocephalus. All patients who presented with an unruptured AICA aneurysm had good clinical outcome (modified Rankin scale [mRS] 1–2). In patients with SAH, 82% achieved good clinical outcome and 18% had poor clinical outcome (mRS 3–6) after 1 year.

Conclusion Surgical treatment of AICA aneurysms has a high rate of cranial nerve deficits but most of patients have a good long-term clinical outcome.

A successful treatment of hemifacial spasm due to anterior inferior cerebellar artery aneurysm in adolescent: a case report and literature review

OBJECTIVE

Hemifacial spasm (HFS) is usually caused by compression of the facial nerve at the root exit zone (REZ), and is extremely rare in adolescents and even rarer in aneurysm compression.

CASE REPORT

We describe symptomatic hemifacial spasm caused by a saccular aneurysm of the anterior inferior cerebellar artery (AICA) that was treated by clipping. A 17-year-old adolescent developed left hemifacial spasm that had gradually worsened over a period of 1 year before admission to our department. During the course of MVD (microvascular decompression), saccular aneurysm of AICA was accidentally found to compress the facial nerve. The cause of the facial spasm was considered to be compression of the left facial nerve by the aneurysm. Clipping the aneurysm was performed. The hemifacial spasm disappeared immediately.

CONCLUSION

Our report indicates that HFS caused by saccular aneurysm of AICA can be treated by clipping, and that aneurysms should be considered in the treatment of adolescent HFS, especially those difficult to identify on imaging examination.

Parent Artery Occlusion against Dissecting Aneurysm Involving the Proximal Anterior Inferior Cerebellar Artery: Case Report and Literature Review

Dissecting aneurysms of the anterior inferior cerebellar artery (AICA) are rare. Few reports suggested that coil embolization and parent artery occlusion (PAO) would be valuable treatment options against dissecting AICA aneurysms. We report a case of PAO against dissecting aneurysm involving the proximal AICA and discuss the therapeutics and literature review of this pathology. A 69-year-old woman was referred to our hospital, and neurological examination revealed a semicoma (Hunt and Hess grade IV). Brain computed tomography (CT) established the diagnosis of Fisher group 3 subarachnoid hemorrhage (SAH), CT angiography revealed an extravasation near the clivus, while digital subtraction angiography showed no signs of dissection. Conservative treatment was administered, and repeated angiography on day 13 showed a pseudoaneurysm and false lumen in the left proximal AICA. The patient was in poor health condition, and endovascular therapy (EVT) of the left AICA was performed to minimize invasion. The PAO was successful with no severe ischemic damage to the brainstem and cerebellum. However, the general condition gradually deteriorated, and the patient expired on day 24. Since open surgery for dissecting AICA aneurysm is technically challenging and revascularization procedure is often required, the rapidly developing EVT is a viable alternative. Although preservation of the proximal AICA is usually necessary, PAO without revascularization procedure was performed to avoid the high risk of regrowth and re-rupture of the dissecting aneurysm with respect to the patient’s poor health condition. Hence, EVT is a viable option when microsurgery is contraindicated for treating dissecting AICA aneurysms.