Devices and methods for treating vascular defects, such as, for example, balloon-type aneurysms, are described herein. In particular an implant configured to be positioned within an aneurysm is described. The implant comprises an expandable mesh formed of a tubular braid flattened along at least a portion of its longitudinal axis such that opposing sidewalls of the tubular braid are urged towards one another, the expandable mesh having a collapsed, elongated configuration and a deployed configuration. When the expandable mesh is in the elongated configuration, the expandable mesh is compressed and configured to be contained in a delivery device, and when the expandable mesh is in the deployed configuration, the expandable mesh has first and second wider portions separated by a constricted portion.
