The primary objective of this study is to demonstrate effectiveness and safety of the Neuroform Atlas Stent System for use with bare metal embolic coils.

The study is a prospective, multicenter, open-label, single arm trial designed to demonstrate the potential treatment of wide neck, intracranial, saccular aneurysms with the Next Generation Neuroform Stent System with any approved embolic coils currently on the market. The study will evaluate the percent occlusion of the treated target lesion on angiography in the absence of retreatment, or parent artery stenosis at the target location at 12 months. Subjects with documented wide neck, intracranial, saccular aneurysms arising from a parent artery may potentially benefit from stent assisted coiling, provided they meet the other eligibility criteria.

Data collected through the 12-month follow-up visit are intended to support Premarket Approval (PMA) application to the Food and Drug Administration (FDA). Long-term follow-up data collected through 3 years postoperative are intended to support post-approval study (PAS) requirements.

Inclusion Criteria:

1. Subject is between 18 and 80 years of age
2. Documented wide neck (neck ≥ 4 mm or a dome-to-neck ratio of < 2), intracranial, saccular aneurysm arising from a parent vessel with a diameter of ≥ 2mm and ≤ 4.5 mm, which will be treated with bare metal coils
3. Subject or legal representative is willing and able to provide informed consent
4. Subject is willing and able to comply with protocol follow-up requirements

Exclusion Criteria:

1. Known multiple untreated cerebral aneurysms, other than non-target blister aneurysm, infundibulum, or aneurysm measuring <3mm for each of three dimensions assessed (height, width, and depth) that will not require treatment during the study period
2. Target lesion is a blister aneurysm, infundibulum, or aneurysm measuring <3mm for each of three dimensions assessed (height, width, and depth)
3. Target aneurysm that will require an Investigator to intentionally leave a neck remnant in order to preserve blood flow in a bifurcation or branch
4. Coiling or stenting of a non-target intracranial aneurysm within 30 days prior to study treatment
5. Target aneurysm is in the anterior circulation proximal to the superior hypophyseal ICA
6. Acute target aneurysm rupture less than 14 days prior to study treatment
7. Hunt and Hess score ≥ 3 or a premorbid mRS score ≥4
8. An admission platelet count of <50,000, any known coagulopathy, or an International Normalized Ratio (INR)>3.0 without oral anticoagulation therapy
9. A known absolute contraindication to angiography
10. Evidence of active cancer, terminal illness or any condition which, in the opinion of the treating physician, would/could prevent subject from completing the study (e.g., a high risk of embolic stroke, atrial fibrillation, co-morbidities, psychiatric disorders, substance abuse, major surgery ≤ 30 days pre-procedure, etc.)
11. Known absolute contraindication to the use of required study medications or agents (e.g., heparin, aspirin, clopidogrel, and radiographic contrast agents, etc.)
12. Female subject who is pregnant or intends to become pregnant during the study
13. Moya-Moya disease, arteriovenous malformation(s), arteriovenous fistula(e), intracranial tumor(s), or intracranial hematoma(s) (unrelated to target aneurysm)
14. Significant atherosclerotic stenosis, significant vessel tortuosity, vasospasm refractory to medication, unfavorable aneurysm morphology or vessel anatomy, or some other condition(s) that, in the opinion of the treating physician, would/could prevent or interfere with access to the target aneurysm and/or successful deployment of the Neuroform Atlas™ Stent
15. Previous treatment (e.g., surgery, stenting) in the parent artery that, in the opinion of the treating physician, would/could prevent or interfere with successful use of the Neuroform Atlas™ Stent System and/or successful adjunctive deployment of embolic coils
16. Previous stent-assisted coiling of the target aneurysm