A significant proportion of patients who undergo sinus surgery for chronic sinusitis later experience recurrent symptoms due to persisting disease and the regrowth of sinus polyps. For many patients this persisting disease proves to be refractory to medical therapy. Treatment options typically include further aggressive medical therapy or repeat sinus surgery. This study is designed to evaluate another treatment option in the form of a steroid-eluting sinus implant that is placed into the sinus and delivers the medication for up to 3 months to reduce sinus inflammation, polyposis and the associated sinus symptoms.