H1: improved HRQoL: a) sinus-disease specific HRQoL as evaluated by the validated Sinonasal Outcomes Test (SNOT-20) questionnaire (primary outcome measure); b) fatigue-specific HRQoL as assessed by the validated questionnaire, the Multidimensional Fatigue Inventory (MFI); and c) overall HRQoL as assessed by the validated questionnaire the Medical Outcomes Survey Short Form-36 (SF-36; mental and physical health domains) augmented with 18 sleep- and breathing related questions.