Objectives: 1- Evaluate the features and CT scan of chronic rhinosinusitis
2- Evaluate the results in patients undergoing Functional Endoscopic Sinus Surgery with navigation system. Subjects and Method: a prospective study with intervention was designed for 32 patients at Rhinology department of National ENT hospital. Results: The most common presenting complaints were nasal obstruction, discharge and olfactory disturbance. Endoscopic assessment: Severe 75 percent, moderate 21.9 percent and mild 3.1 percent. CT scan assessment: Severe 50 percent and moderate 50 percent. The type of surgery: 46.9 percent type V
46.9 percent type IV and 6.2 percent type III 32 patients were followed up after 6 months, 10 patients were followed up after 12 months. Most of patients were better post endoscope sinus surgery with navigation system. Conclusion: FESS with the assistance of a navigation system is useful in patients with chronic sinusitis grade moderate, severe and the patients require revision sinus surgery.