Study of the variations of the optic canal by multi-slice spiral CT

Abstract

Objective To explore the relationship between the posterior ethmoid sinuses, the sphenoid sinus and the optic canal. Methods Two hundred and sixty (520 sides) sinus CT scans were reviewed. The images were transferred to work station for MPR analysis. All data were analyzed by X2 test. Results The prevalence of type 0 to 4 CNII was 4. 4% (23 sides), 19. 2% (100 sides), 26. 0% (135 sides), 29. 0% (151 sides), 21.4% (111 sides) ,respectively; The prevalence of onodi cell was 41.9% (218 sides) ; the pneumatizafion of anterior clinoid process was 12. 3% (64 sides) ; The prevalence of type parasphenoid, paraethmoid and ethmoid-spheanid CNII was 46. 5% (242 sides), 26. 7% (139 sides) ,22. 3% (116 sides), respectively. Among the onodi cell, The prevalence of type 3 and 4 optic canal and paraethmoid and ethmoid-sphenoid optic canal was more than the preceding sphenoid ethmoid cell significantly. Conclusions MPR and multi-slice spiral CT can facilitate precise study of the anatomical relationship of CNII. Caution must be taken during sinonasal surgery to minimize the risk of inadvertent CNII injury. Key words: Optic nerve; Ethmoid sinus; Sphenoid sinus ; Tomography; X-ray computed