Supraorbital ethmoid cell: A consistent landmark for endoscopic identification of the anterior ethmoidal artery

Objective. To demonstrate that the supraorbital ethmoid cell (SOEC) is a consistent and reliable landmark in identification of the anterior ethmoidal artery (AEA).

Study Design. Retrospective radiographic study.

Setting. Tertiary care rhinology practice.

Subjects and Methods. The computed tomography (CT) scans for 78 consecutive patients were evaluated for the presence of SOECs, degree of pneumatization, and location of the AEA in relation to fixed anatomic structures. Forty-one patients with normal SOECs were identified and compared with a group of 15 patients with pathological expansion of the SOEC secondary to inflammatory disease. The CT findings were correlated with endoscopic findings.

Results. The incidence of SOECs was 53%. Compared to normal SOECs, expanded SOECs had significantly greater pneumatization laterally (9.3 vs 18.5 mm, respectively; P < .0001) and AEAs that were significantly farther from the skull base (1.3 vs 6.6 mm, respectively; P <.0001). The distance between the AEA and the nasal beak was similar between the 2 groups (P = .1). More importantly, 68 of 68 sides with normal SOECs (100%) demonstrated the AEA within or in continuity with the posterior border of the SOEC opening. In patients with pathological expansion, the AEA remained within the posterior border of the SOEC opening in 19 of 19 sides (100%), despite significant expansion of the cell superolaterally.

Conclusion. This is the first study to demonstrate a consistent landmark to identify the AEA even in cases of distorted anatomy of the frontal recess. Identifying the SOEC is a practical and reliable technique for minimizing the risk of injury to the AEA during frontal recess surgery.