What is Sinus Surgery? Sinus surgery, also known as endoscopic sinus surgery, is a medical procedure performed to treat chronic sinusitis or other sinus-related conditions. It involves the removal of blockages or abnormal growths in the sinus cavities, allowing for improved drainage and airflow. Common Conditions Treated with Sinus Surgery Chronic sinusitis Nasal polyps Deviated nasal septum Sinus infections resistant to medical treatment