Tissue collection
Two ethmoid sinus tissue biopsies were collected by an Ear, Nose and Throat surgeon at baseline and at weeks 4, 8, 16 and 24 following the administration of local anaesthetic to each nostril (300µL, 5% lignocaine hydrochloride/0.5% phenylephrine hydrochloride). One biopsy was fixed in 10% neutral buffered formalin for histopathology and the second snap-frozen in liquid nitrogen, and stored at -170oC until further processing.