Vertebral artery access considerations in coil embolization of small superior cerebellar artery aneurysm.

BACKGROUND: Coiling of small superior cerebellar artery (SCA) aneurysms (sSCAAs) is challenging. We aimed to describe anatomical considerations in the vertebral and basilar artery (VA and BA) morphology for decision-making in coiling of sSCAAs.

METHODS: 11 patients with sSCAAs (<5mm) treated at our institution between April 2015 and Februrary 2022 were included to show our concept of deciding access routes in coiling of sSCAAs. The access route was decided based on VA characteristics, BA curvature, and aneurysm laterality. Adequate aneurysm occlusion on angiography (Raymond-Roy grading scale I and II), good outcome (modified Rankin Score 0-2) at the last follow-up, and adverse outcomes were evaluated.

RESULT: Simple coiling (n=2), a balloon-assisted technique (n=3), and stent-assisted technique (n=6) were selected. At the last follow-up (median 13.0 months), adequate aneurysm occlusion and good outcome were obtained in all and 9 patients (n= 10). Adverse outcomes were not observed. When VA dominance was equal, in the straight BA, the microcatheter-insertion into the ipsilateral VA to the aneurysm was favorable to form a "fulcrum" on the contralateral side and obtain the microcatheter stability. When aneurysm was on the concave aspect of the curved BA, the microcatheter-insertion into ipsilateral VA was favorable. As for the convex aspects aneurysm location, the microcatheter-insertion into the contralateral VA can be favored. Further, we described a the VA origin classification as it relates to ease of access from a transradial approach.

CONCLUSIONS: Vertebrobasilar morphology may be important in deciding access routes in the coiling of sSCAAs.