Single coil endovascular embolization of very tiny (≤2 mm) intracranial aneurysms: one center's experience

Background: To investigate the safety and efficacy of endovascular embolization of very tiny (≤2 mm) intracranial aneurysms with single coil and summarize experience. Methods: A retrospective analysis was performed for 15 consecutive patients with very tiny aneurysms treated by coil embolization alone or stent-assisted coil embolization between January 2017 and January 2020. 15 patients with six unruptured aneurysms and nine ruptured aneurysms were included in this study. There were eight males and seven females with a mean age of 50.0 ± 5.2 years (range 41 to 57 years old). Intraoperative complications, imaging outcomes, clinical outcomes and follow-up data were analyzed. Results: All aneurysms were embolized with a single coil. Lvis stents were used in all coil assisted embolizations. The embolization success rate was 100%. The average volume embolization ratio (VER) of aneurysm embolization was 53.7 ± 25.5%. An intraoperative aneurysm re-rupture complication occurred in one patient (6.7%). 11 patients (73.3%) had immediate complete occlusion after embolization. After a mean follow-up period of 6.7 ± 1.4 months, 13 patients (86.7%) had complete occlusion. No patients had aneurysm re-rupture, an ischemic event or recurrence during follow-up. All patients achieved favorable clinical outcomes with a modified rankin scale (MRS) of 0-2. Conclusions: This study demonstrates that endovascular embolization of very tiny intracranial aneurysms with a single coil is safe and effective. However, the follow-up period was not long enough and studies with larger numbers of patients are required. The summary of experience reported here is expected to provide significant patient benefits.