Is there a relationship between Onodi cell and optic canal?

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

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.

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.

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.