Background Knowledge of the anatomic variations reduces the surgical complication rates during
FESS, helps explain recurrence of disease and allows one to change the operative technique. These
variations can be the etiological factor for sinusitis and spread of infection to adjacent structures. The
aim of this study is to investigate variations in paranasal sinuses discovered at CT scan, explain their
spectrum, and prevalence as well as clinical and surgical implications. Patients and methods This study
is a retrospective cross-sectional study where about 500 Egyptian patients were included for routine
MSCT of the paranasal sinuses from Banha University Hospitals during January 2019 to January 2020.
In all the included patients, we gathered data regarding complete history of symptoms, findings of ENT
examination and MSCT examination of the paranasal sinuses (PNS). Results The mean age of the
studied patients was 29 ±14 years. About half of the patients were males (45.8%), and the other half
were females (54.2%). The most frequent symptom was headache (77.4%), followed by nasal
obstruction (76.0%), discharge (61.6%), blurring of vision (25.0%), and vertigo (6.0%). The most
frequent variations were agar nasi reported in (86.4%), nasal septal deviation (76.2%), sphenoid sinus
septation (74.2%), Maxillary sinus hyper-pneumatization (66.0%), Haller cell (65.8%) & Frontal sinus
septation (60.2%). Agar nasi was significantly higher in those with sinusitis (95.3%) than those without
(75.3) (P < 0.01). Also, haller cell was significantly higher in those with sinusitis (93.5%) than those
without (31.4%) (P < 0.001). Conclusion MSCT on paranasal sinus plays an important role in
preoperative assessment by detecting paranasal sinus variations preventing possible injuries of
important structures beside detection of anatomical variant and their relation to sinusitis.