Substance delivering spacer devices may comprise expandable reservoirs that are implantable in paranasal sinuses and other cavities, openings and passageways of the body to maintain patency and to provide sustained local delivery of a therapeutic or diagnostic substance. Delivery apparatus including...http://www.google.es/patents/US20090198216?utm_source=gb-gplus-sharePatente US20090198216 - FRONTAL SINUS SPACER
