The invention relates to a medical retrieval device with a basket that has at least one leg that is frangible (i.e., easily breakable) and/or able to dissociate from at least one other leg upon the application of a predetermined force to the basket. The invention allows an operator to release captured material (e.g., a stone) from the basket when the device is still inserted in the body. In an embodiment, the basket legs associate by a magnetic interaction that can be overcome by applying a predetermined force to the basket. In another embodiment, at least a portion of at least one basket leg is made from, or coated with, a substance that is adhesive or that joins at least two legs together when the substance is solid but which melts, dissolves or weakens upon the application of an electrical, thermal or chemical change. In yet another embodiment, the invention provides a basket with at least two legs that are joined together by a joining member that can break, or from which one or more legs can dissociate, upon the application of a predetermined force. In yet another embodiment, the invention provides a basket with at least two legs that are joined together by a joining member by means of at least one shear pin that can break upon the application of a predetermined force.