Objectives:
The present research set out to assess the impact of functional endoscopic sinus surgery (FESS) on patients’ persistent sinusitis-related odor dysfunction. Also, the impact of FESS on nasal airway resistance using an indirect, objective technique, the nasometer.

Materials and methods:
A prospective study of 40 patients with bilateral nasal polyposis and smell impairment was conducted. 16 men and 24 women, ages 15-69, with a mean age of 37.7 years, were recruited among E.N.T. clinic attendees at El Zahraa Hospital, Al-Azhar University and El Demerdash Hospital, Ain Shams University from January 2021 till May 2022.

Results:
Identifying olfactory impairment before surgery revealed anosmia in 85% and hyposmia in 15%. A considerable improvement was seen after surgery, with anosmia in 32.5% of patients, hyposmia in 10.0%, and normosmia in 57.5%. Patients had an average nasalance level of 31.7 ± 18.9 (3.3-69.7) before surgery and an average oral sentence level of 14.7 ± 10.0 (3.1-46.6). Normal persons have a nasalance score of 54.7 ± 5.8% for nasal phrases. However, it rose to 61.9 ± 13.3, with a range of 16.3-75.1. This requires lowering nasal airway resistance in all surgical patients for up to a year since nasalance and resistance are inversely related.

Conclusions:
After endoscopic sinus surgery, olfactory dysfunction and nasalance scores improved. Olfactory impairment is a crucial problem for the quality of life and patient safety of those with chronic rhinosinusitis with nasal polyps, which calls for more investigation.