Clinical and Angiographic Effects of Endovascular Coil Embolization of Very Small Intracranial Aneurysms

Objective: Treatment of very small cerebral aneurysms remains challenging. The aim of the present study was to assess the feasibility and safety of endovascular treatment for these aneurysms.Methods: Between 2003 and 2008, a total of 831 aneurysms were selectively occluded with coils. Of these aneurysms, 110 (13.2%) were very small (57 ruptured and 53 unruptured). We performed a retrospective analysis of these cases using the Glasgow outcome scale (GOS) for clinical followup and digital subtraction angiography (DSA) and/or MR angiography (MRA) for angiographic followup.Results: Mean duration of followup was approximately one year. Overall clinical outcome of patients showed 78 patients (76.5%) with good recovery, six (5.9%) with moderate disability, nine (8.8%) with severe disability, five (4.9%) with vegetative state, and four (3.9%) that had died. All asymptomatic unruptured aneurysms showed good recovery. No delayed rebleeding was observed. There were no procedural related complications. We encountered major recanalization in four aneurysms (10%) of the followedup ruptured aneurysms, requiring retreatment with coils; there were no major recanalizations in cases of unruptured aneurysms. Six out of nine (67%) unruptured aneurysms showing initial body filling had changed into complete occlusion at later follow up. Conclusions: Endovascular treatment may be a feasible and effective therapeutic alternative for very small aneurysms. Endovascular coil embolization of very small ruptured aneurysms was effective in controlling hemorrhage; however, this technique requires strict followup and may necessitate additional treatment. By contrast, outcome of very small unruptured aneurysms was excellent.