The investigator expects that endovascular flow-diversion is superior over revascularization by postoperative modified Rankin scale (mRS) in patients with complex intracranial aneurysms.

Open, prospective, controlled randomized superiority trial is conducted. The hypothesis is that endovascular flow-diversion is better than revascularization in treatment of complex intracranial aneurysms by postoperative modified Rankin Scale (mRS). Sample size was measured by Fisher exact test. Depending on a type of the procedure, the patients are divided into two groups: Endovascular Flow Diversion Procedure (include 55 patients) and Revascularization Procedure (include 55 patients). Randomization is performed by random number generation.The study was approved by Institutional Review Board

Inclusion Criteria:

• anterior circulation complex intracranial aneurysm
• neck is more than 4 mm wide
• dome/neck ratio of aneurysm equals or less than 2:1
• age less than 75 years
• ability to give informed consent (subject or legally authorized representative)
• aneurysm is suitable for treatment to both procedures

Exclusion Criteria:

• subarachnoid hemorrhage less than 30 days ago
• contraindications to endovascular treatment
• atypical aneurysms (mycotic, flow-related in patients with AVM, traumatic, false)
• informed consent refusal