An aneurysm occlusion system includes a device positionable within a cerebral blood vessel covering a neck of an aneurysm on the blood vessel. The device includes an expandable tubular element having a lumen surrounded by a sidewall including a plurality of gaps. When expanded, the tubular element includes longitudinal standards arrayed helically in a proximal to distal direction. The standards support struts and the gaps are defined between adjacent struts and are sufficiently large to permit delivery of embolic coils or other embolic materials therethrough.