Background: The main goal was to assess aneurysm recurrence on follow-up angiography and clinical outcome at 12 to 18 months after coil placement.
Material/Methods: Eighty-two consecutive patients with a cerebral aneurysm (54 women and 28 men) aged from 32 to 71 years old (mean age, 56 years) were selected for intraarterial embolization in the anterior and posterior intracranial circulations and were treated with hydrocoils. The size of all aneurysms ranged from 2 to 26 mm in maximal diameter. We described aneurysms as small (≤7 mm), large (8–15 mm), very large (16–24 mm), and giant (≥25 mm).
Results: Hydrocoil coiling was successful in 97.6% (80). Balloon remodeling technique was used in 47.6% (39) patients and combined with Enterprise stent-coil embolization in 14.6% (12) other patients. The 12- to 18-month recurrence rate independent of the aneurysm size was 13.4% (11). The recurrence rate for small aneurysms was 3%, and the combined recurrence rate for small and large aneurysms was 8%. The combined recurrence rate for very large and giant aneurysms was 60%. The neurologic complication rate was 15%, of which 5% represented permanent neurologic deficits.
Conclusions: The hydrocoil embolization system is safe and provides excellent 12- to 18-month occlusion of small and large aneurysms. Very large and giant aneurysms are not as successfully occluded by this system.

Keywords: hydrogel-coated coils, cerebral aneurysms, embolization