Incidence and Types of Sphenoethmoid Cell in Patients with Chronic Paranasal Sinusitis

Chung, Seung Kyu; Kim, Hyo Yeol; Yoon, Seong Won

Abstract

The sphenoethmoid cell is the most posterior ethmoid cell, pneumatizing far laterally and to some degree superiorly to the sphenoid sinus. A accurate understanding of the sphenoethmoid cell is important for avoiding fatal injury to the orbit and safely approaching the sphenoid sinus. To investigate the incidence of sphenoethmoid cells, the authors analyzed the coronal CT scans of 50 patients who underwent endoscopic sinus surgery for sinusitis. Sphenoethmoid cells were identified in 39 out of 100 nasal cavities and divided into two types according to their relationship with the optic canal and the sphenoid sinus : type 1 cells, where the optic nerve bordered the sphenoethmoid cell and the sphenoid sinus, were observed in 14 cavities, and type 2 cells, where the optic nerve bordered only the sphenoethmoid cell, were observed in 25 cavities. We anticipate the existence of an optic canal in the posterior ethmoid sinus in one third of the cases, and the direction of the approach to the anterior wall of the sphenoid sinus should be modified according to the type of sphenoethmoid cell if one is present.