Software-enabled CT analysis of optic nerve position and paranasal sinus pneumatization patterns

Abstract

Delineate the relationships among the optic nerve (CN II), the sphenoid sinus, and the sphenoethmoid cell. High-resolution CT scans of 64 frozen human cadavers were obtained on a Siemens VolumeZoom CT scanner (Munich, Germany) and transferred to a CBYON Suite Doctor Station version 2.6 (CBYON, Mountain View CA) for standardized review. Pneumatization around CN II was categorized into 5 types: no adjacent pneumatization (type 0), pneumatization adjacent to CN II (type 1), adjacent pneumatization with indentation (type 2), pneumatization of <50% CN II circumference (type 3), and pneumatization of >50% CN II circumference (type 4). The prevalence of types 0 to 4 CN II position relative to the sphenoid sinus was 4.7%, 25.8%, 39.8%, 14.1%, and 15.6%, respectively. The prevalence of sphenoethmoid cells was 28.1%. The prevalences of types 0, 1, 2, 3, and 4 CN II positions relative to the sphenoethmoid cell was 5.6%, 58.3%, 25%, 2.8%, and 8.3% respectively. Software-enabled CT review facilitated precise study of the anatomic relationships of CN II. Caution must be exercised during sinonasal surgery to minimize the risk of inadvertent CN II injury. D.