Distal aneurysms of cerebellar arteries: incidence, clinical presentation, and outcome of endovascular parent vessel occlusion

Abstract

Background and purpose: The aim of this retrospective study was to report the incidence, clinical presentation, and midterm clinical and imaging results of endovascular parent vessel occlusion of 11 patients with 13 distal cerebellar artery aneurysms.

Materials and methods: Between January 1995 and December 2006, 2201 aneurysms were treated in our institution. Thirteen aneurysms in 11 patients were located on distal cerebellar arteries (incidence, 0.6%), 8 of them arising from vessels feeding small arteriovenous malformations. There were 6 men and 5 women, ranging from 44 to 70 years of age. One patient with a superior cerebellar artery aneurysm presented with isolated trochlear nerve palsy. Ten patients presented with subarachnoid and intraventricular hemorrhage, and most patients were in poor clinical condition on admission. Aneurysm location was the superior cerebellar artery in 3, the anterior inferior cerebellar artery in 5, and the posterior inferior cerebellar artery in 5. Two patients had 2 aneurysms each.

Results: Eleven aneurysms were treated by simultaneous coil occlusion of the aneurysm and parent artery or occlusion of the parent artery just proximal to the aneurysm. Clinical follow-up was at a mean of 16.5 months (range, 2-40 months). Infarction in the territory of the occluded vessel was apparent on follow-up imaging in 5 of 11 patients, all without functional impairment.

Conclusion: Distal cerebellar artery aneurysms are rare. Most patients present with poor-grade hemorrhage. Endovascular parent vessel occlusion is effective in excluding the aneurysm from the circulation. In most patients, adequate collateral circulation prevents infarction in the territory of the occluded vessel. In this series, when infarction did occur, the clinical consequences were limited.

Fig 1.

A 59-year-old woman with isolated right trochlear nerve palsy. A, MR image demonstrates a partially thrombosed aneurysm lateral to the brain stem. B, A 3D angiogram shows a distal SCA aneurysm (arrow). C, Detail of the 3D angiogram reveals an aneurysm without a neck (double arrow) on the rostral trunk of SCA (arrow).

Fig 2.

A 68-year-old woman with hemorrhage from a distal SCA aneurysm. A, CT scan shows subarachnoid and intraventricular blood and vermian hematoma. B, A 3D angiogram demonstrates a fusiform aneurysm of the caudal trunk of the SCA (small arrow). Also a small AVM is apparent (large arrow). C and D, Angiograms before (C) and after (D) occlusion of the aneurysm and parent vessel with coils.

Fig 3.

A 69-year-old woman with hemorrhage from a distal AICA aneurysm. A, A right vertebral angiogram shows a small distal AICA aneurysm (arrow). B, Detail of 3D right vertebral angiogram shows a distal AICA aneurysm without a neck. C, A microcatheter in the AICA just proximal to the aneurysm. The AICA was occluded with coils at this level.

Fig 4.

A 57-year-old woman with hemorrhage from a distal PICA aneurysm. A, A 3D angiogram demonstrates an aneurysm on the medial cortical branch of the right PICA (arrow), supplying a small torcular AVM, not well demonstrated in this threshold setting (circle). The aneurysm was occluded with coils, including the parent vessel. B, CT scan after 2 weeks reveals infarction in the medial territory of the right PICA.