Morphometric evaluation of the anatomical relationship of fissura orbitalis superior and orbital structures in computed tomography images and its clinical significance

Objective: It was planned to examine the morphometric measurements of fissura orbitalis superior (FOS) and canalis opticus (CO), which are important anatomical structures that assist in surgical planning in orbital endoscopic approaches, by multislice computed tomography (MDCT) and to evaluate them according to age and gender. It was aimed to contribute to the anatomical and clinical evaluations by comparing the obtained findings with the literature findings. Methods: A total of 219 MSCT images (114 women, 105 men) aged 18-90 years were retrospectively analyzed in the study. Morphometric measurements of FOS and CO were performed on CT images in the axial plane and with 3D-Slicer software. Results: The length of the FOS and the three-dimensional width parameters of the FOS were found to be significantly higher in women than in men (p <0.05). According to FOS classifications, the length of FOS was found to be highest in type II and lowest in type VIII (p<0.05). According to FOS classifications, the width of FOS was found to be highest in type I and lowest in type VI (p<0.05). The distances between the foramen infraorbitalis of the anterior entrance of the sinus maxillaris and the lateral end point of the FOS and the angle values between the lateral and medial end points of the FOS were found to be significantly higher in women than in men (p <0.05). The lateral wall length of the CO was found to be statistically significantly higher in men than in women. There was no significant difference between the parties and age groups in all measured parameters (p>0.05). Conclusion: Since the FOS shows many variations in shape and size and a narrow FOS may cause compression of the nerves and vessels passing through this region after trauma or surgery, it is necessary to know the microanatomy of the FOS for the interventions to be performed in this region. In this respect, we believe that the results of this study may contribute to clinicians to perform safer operations in endoscopic procedures. Keywords: 3D computed tomography, Morphometry, Orbita, Optic canal, Superior orbital fissura, Variation.