Implantable device and methods for delivering drugs and other substances to treat sinusitis and other disorders

A method for using a transnasally insertable implantable substance delivery device for delivering a diagnostic or therapeutic substance to a location within a paranasal sinus or paranasal sinus ostium of a human or animal subject, said method comprising the steps of:

• A) providing a device that comprises i) an expandable reservoir that is initially substantially in a collapsed configuration, said collapsed configuration being sufficiently small to allow the reservoir, while in said collapsed configuration, to be inserted through a nostril of the subject and advanced to said location within a paranasal sinus or paranasal sinus ostium, said reservoir being thereafter expandable to an expanded configuration;
• ii) a tube extending from said reservoir, said tube having a lumen through which a quantity of the substance may be introduced into the reservoir;
• iii) a barrier through which the substance will elute from the reservoir, thereby causing the substance to be delivered to said location within the paranasal sinus or paranasal sinus ostiun;
• and iv) a closure apparatus for preventing the substance from backflowing out of the tube after the substance has been introduced into the reservoir;
• B) inserting the device, with the reservoir in the collapsed configuration, through a nostril of the subject and positioning the reservoir within a paranasal sinus or paranasal sinus ostim;
• C) introducing a quantity of the substance through the tube and into the reservoir, thereby causing the reservoir to assume the expanded configuration;
• and
• D) delivering at least some of the substance out of the reservoir to said location within the paranasal sinus or paranasal sinus ostium by leaving the device implanted within the paranasal sinus or paranasal sinus ostium for a period of time such that the substance will elute through the barrier.