Evaluation of Optic Canal and Surrounding Structures Using Cone Beam Computed Tomography: Considerations for Maxillofacial Surgery

The optic canal connects the anterior cranial fossa and the orbit and maintains the optic nerve and the ophthalmic artery. Within the extent of the surgical approach of the region, risk of iatrogenic injury of the neural and vascular structures increases. The aim of this retrospective morphometric study is to investigate the radiological anatomy of orbita, optic canal, and its surrounding using cone beam computed tomography (CBCT) scans in a group of Turkish population. Cone beam computed tomography images of a total of 182 patients were evaluated by 2 observers. Anatomical parameters regarding optic canal and orbita were measured for all patients from axial, sagittal, and three-dimensional reconstructed images. To assess intraobserver reliability, the Wilcoxon matched-pairs test was used. Pearson chi(2) test and Student t test were performed for statistical analysis of differences, sex, localization, and measurements (P<0.05). Repeated CBCT evaluation and measurements indicated no significant inter and intra-observer difference were found (P>0.05). The orbita width and height were larger for the males than females (P<0.05). No significant difference was observed for optic canal shape, dimensions of infraorbital foramen (IOF) and supraorbital foramen (SOF), SOF-midline distance, and SOF-IOF distance according to sex and location (P>0.05). Examination CBCT scans revealed that the shape of the optic canal was 70% funnel and 28% Hourglass shape, 2% amorph type round. These results provide detailed knowledge of the anatomical characteristics in the orbital area which may be of assistance for surgeons preoperatively. Cone beam computed tomography scans can be an alternative modality for multislice computed tomography with submillimeter resolution and lower dose in preoperative imaging of the orbit.