The association between supraorbital ethmoid air cells and orbital proptosis in patients with chronic rhinosinusitis

Background: Orbital proptosis is a known possible complication in patients with chronic rhinosinusitis (CRS). This study was undertaken to determine the association of sinus anatomy and anatomic variants with the predisposition for such a complication. Methods: All adult patients (n = 16) with orbital proptosis were identified from a prospectively-collected database at a tertiary institution. These were compared with a series of randomly-selected patients (n = 50) diagnosed with chronic sinusitis and who had undergone sinus computed tomography. The presence or absence of supraorbital ethmoid air cells (SOECs) was noted and compared between the 2 groups. The primary sinus anatomy responsible for the proptosis was also identified. Statistical analysis was performed using the chi squared test. Results: Sixteen patients with orbital proptosis were identified, of which all but 1 had SOECs present. Causal analysis showed that in all but 1 case the SOECs were the cause of proptosis. Of the 50 patients with CRS but without proptosis, only 13 had SOECs present and 37 patients did not (chi squared = 22.8, p = 0.000002). Conclusion: SOECs appear to be highly associated with and most often are responsible for orbital proptosis in patients with CRS.