Disclosed herein are devices, designs, methods of manufacturing and using medical devices comprising expandable bodies for treating saccular vascular aneurysms and occluding segments of blood vessels and other biological conduits. Exemplary expandable bodies include hollow gold structures that can be folded, wrapped, and compressed, joined to a delivery device, advanced to location in the body of patient in need of treatment, expanded by injection of a fluid into the central void, and separated from the delivery device, remaining in place in an open, expanded form without the addition of support structures to the central void. Other expandable bodies include coiled wires that can be loaded into delivery catheters and expelled from the delivery catheters using pusher devices. Also disclosed herein, are methods of using multiple medical devices and expandable bodies where the expandable bodies are placed adjacent to each other to occlude a saccular aneurysm.