Abstract:
Objective When small unruptured aneurysms (SUA) are embolized by coils, manipulation of the
microcatheter and coil is limited because of their small size. Previous studies suggested
that the morphology of the artery and aneurysm is important. In the present study,
we clarified the morphological factors affecting coil-only embolization of SUA.
Patients and Methods We retrospectively identified 17 patients who underwent embolization for unruptured
aneurysm with a maximum diameter less than 5 mm. We investigated the following: (1)
the relationships among dome/neck ratio (D/N), height/neck ratio (H/N), height/dome
ratio (H/D), projection of aneurysm-parent artery, and adverse events, (2) immediate
and late occlusion, and (3) number of coils.
Results (1) Adverse events developed in three cases in which the H/D was smaller than 1 (p < 0.02). There was a significant difference in the rate of adverse events by projection
of the aneurysm-parent artery (p < 0.03), (2) Occlusion rate: Immediately after coil embolization, 71% (12/17) were
neck remnant; however, 88% (15/17) of SUA became complete occlusion in the follow-up
term, and (3) 1.5 ± 0.6 coils were used.
Conclusion To achieve successful coil-only embolization in SUAs, it is important to select aneurysms
for which the projection of the parent artery is suitable for embolizing and the H/D
ratio is larger than 1. In SUAs, occlusion develops naturally after coil embolization.
Keywords
coil embolization - height dome ratio - morphology - parent artery-aneurysm projection
- small aneurysm
