A stent is designed to be placed in a lumen of a patient and extend therethrough. The stent includes a distal end and a proximal end. The distal end includes a distal retention structure and the proximal end includes a plurality of radially extending flexible segments to prevent migration of the stent...http://www.google.com.au/patents/US7357818?utm_source=gb-gplus-sharePatent US7357818 - Self-retaining stent
