Is there a relationship between Onodi cell and optic canal?

Objective: We investigated the relationship between Onodi cells and optic canal by paranasal sinus computed tomography (PNSCT).

Methods: In this retrospective study, 508 PNSCT (265 males and 243 females) was examined. Onodi cell presence, pneumatization types, optic canal types; and also sphenoid sinusitis and anterior clinoid process pneumatization were evaluated.

Results: The prevalence of Onodi cells was 21.2% of the patients. Onodi cells were observed 40.7% on the right side and 25.9% on the left side. In 33.4% of the patients, bilateral Onodi cells were present. Male/Female ratio was 24.5%/17.6%. Onodi cell types were detected as Type I > Type II > Type III bilaterally. There was a positive correlation between the right and left Onodi cell types (p < 0.05). Optic canal types were detected as Type IV > Type I > Type II > Type III. bilaterally. There was a positive correlation between right and left optic canal types. Onodi cell presence and ACP pneumatization were found as statistically significant (p < 0.05). In 65.5% of the patients, Onodi cells and ACP pneumatization were absent. ACP pneumatization was present in 35.4% of the cases. In nine cases, bilateral Onodi cells and ACP pneumatization were detected. Sphenoid sinusitis was detected in 11.4% of Type I and 13.8% of the Type II Onodi cells on the right side. On the left side, it was detected in 12.9% of the Type I and 19.0% of Type II Onodi cells.

Conclusions: Identification of Onodi cell is very important clinically because of its proximity to optic nerve canal. We concluded that type IV Onodi-optic canal relationship was the most common finding in our study. Onodi cell presence and their patterns of pneumatization must be evaluated on PNSCT preoperatively to avoid optic canal damage.