The Anatomical relationship of Optic Nerve Canal to the Posterior Paranasal Sinuses On Computerized Tomography in Iraqi Patients
Keywords:
paranasal sinus, computerized tomography, optic nerveAbstract
Objective: To determine the patterns of relationship between optic nerve canal and posterior paranasal sinuses (PNS) in Iraqi patients from Middle Euphrates region using computerized tomography (CT).
Methods:A cross-sectional observational study was conducted on 100 patients (52male, 48 female) referred to the CT unit for evaluation of PNS. Patients were examined by the same CT devise without intravenous contrast medium. Patients with sphenoid/ethmoid tumours, trauma or history of surgical intervention andthose less than 13 years oldwere excluded.The relationship between optic canal and posterior PNSwas evaluatedusing criteria of Delano's classification. Pneumatization of the anterior and posterior clinoid processes (PACP and PPCP) and any bony dehiscence in the bony wall were observed.
Results: The most frequent type of optic canal according to Delano's classification was type I (77.5). There was no statistically significant age or gender difference. There was statistically significant higher frequency of dehiscence in higher Delano's types III (4 of 7 cases, 57.1%) and IV (6 of 8, 75%). PACP and PPCP showed statistically significant association with type IV and to lesser extent in type III. All cases of PPCP were seen only in type III and IV with statistically significant difference.
Conclusion:The relationship between optic nerve and sphenoid sinuses was slightly different in our patients from other populations. Therefore, Iraqi radiologists and Ear-Nose-Throat surgeons need to be aware of this anatomical difference to avoid serious damage to the optic nerve. During pre-operative CT assessment, it is important for radiologist to pay attention to the presence of optic canal bony dehiscence in higher Delano's types.Presence of PACP and PPCP may alert to the presence of higher Delano's types, hence a serious optic nerve canal course.
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