A medical flow restrictor that may be used to exclude a saccular aneurysm from the circulatory system. The device, a thin walled, foil-like shell, is compacted for delivery. The invention includes the device, electroforming fabrication methods, delivery assemblies, and methods of placing, and using, the device. A device with an aneurysm lobe and an artery lobe self-aligns its waist at the neck of an aneurysm as the device shell is pressure expanded. Negative pressure is used to collapse both the aneurysm lobe and the artery lobe, captivating the neck of the aneurysm and securing the device. The device works for aneurysms at bifurcations and aneurysms near side-branch arteries. The device, unlike endovascular coiling, excludes the weak neck of the aneurysm from circulation, while leaving the aneurysm relatively empty. Unlike stent-based exclusion, the device does not block perforator arteries. This exclusion device can also limit flow through body lumens or orifices.