Coil Embolization of Very Small (2 mm or Smaller) Berry Aneurysms: Feasibility and Technical Issues

Abstract

BACKGROUND AND PURPOSE: The very small size of cerebral aneurysms is considered to be one of the limitations for endovascular treatment, with a high risk for intraoperative rupture. We report on treatment of very small saccular ruptured cerebral aneurysms by coil embolization. All the cases were of 2-mm aneurysms with at least 1 of the dimensions being less than 2 mm.

MATERIALS AND METHODS: We performed retrospective analysis of 7 consecutive cases of very small aneurysms treated by coil embolization in our institution between July 2006 and April 2008.

RESULTS: 3D rotational angiography (3DRA) was found to be most accurate in the detection of these aneurysms; in 2 cases, 3DRA revealed the aneurysms after results on digital subtraction angiography (DSA) were considered to be negative. Coil embolization was successfully performed in 6 cases, whereas in 1 case, spontaneous thrombosis occurred after microcatheter placement. Complete (n = 5) or near complete (n = 2) immediate occlusion was seen. A single soft coil was used in all cases with the shortest available length. Balloon assistance was used in 3 cases. Although minimal coil projection in the parent vessel was seen in 3 cases, no untoward clinical complication was seen. Follow-up DSA and MR angiography in 4 patients demonstrated persistent occlusion (n = 3) or progressive thrombosis (n = 1) of the aneurysms. All of the patients with available follow-up are independent in day-to-day activities with a modified Rankin Score (mRS) of 0 or 1.

CONCLUSIONS: Coil embolization of very small ruptured cerebral aneurysms is feasible. Careful consideration of the technical issues in treatment of these cases is essential to achieve technical success while avoiding complications.