A 52-year-old man with a 2-year history of recurrent nasal congestion, chronic post-nasal drip, and anosmia presents with persistent facial pressure and nasal obstruction despite three courses of antibiotics in the past year. Examination reveals pale, boggy nasal mucosa bilaterally and multiple smooth, grayish masses obstructing the nasal passages. Nasal endoscopy shows polyps originating from the maxillary and ethmoid sinuses. CT imaging demonstrates opacification of the maxillary and ethmoid sinuses with smooth, rounded densities. What is the most appropriate next step in management?