Abstract: A retrieval device for use in renal, biliary, vascular or other systems of a body includes a collapsible basket in a narrow sheath. A surgeon advances the device beyond an object to be removed from a body, such as a kidneystone, a gallstone, or a thrombus. The surgeon then retracts the sheath or advances the basket from the sheath. The basket deploys only to one side of the sheath. In some embodiments, the periphery of the basket has a flex point to enable the basket to easily collapse into the sheath. If the sheath is adjacent a body vessel, such as a blood vessel or a ureter, the sheath remains adjacent the wall, while the device deploys in such a manner as to seal against the walls of the vessel and block the flow of fragments, emboli, thrombi, or other undesirable objects.