The imaging anatomy of ethmomaxillary sinus and its impact on chronic rhinosinusitis.

Purpose: The aim of this study was to investigate the pneumatization degree of ethmomaxillary sinus (EMS) and adjacent structures, and its impact on chronic rhinosinusitis (CRS). Methods: A retrospective analysis of paranasal sinus CT scans of 996 patients was conducted. The maximum vertical diameter of EMS in the coronal plane was measured, allowing EMS to be classified, and its impact on ipsilateral CRS were examined. Results: The prevalence of EMS was 11.9%. The maximum vertical diameter of EMS in the coronal plane ranged from 3.68 to 28.76 mm with a mean (± SD) of 11.32 ± 5.12 mm. The prevalence rates of EMS in CRS sides and non-CRS sides were 12.5% and 9.3%, respectively, which was significantly different (χ2 = 4.495; p < 0.05). The difference in prevalence between the three types of EMS in ipsilateral CRS was statistically significant (χ2 = 6.733; p < 0.05). The difference in Lund–Mackay (LM) score of ipsilateral CRS between the three types showed no statistically significant difference (H = 4.033; p > 0.05). Conclusion: EMS is a common anatomical variation with marked individual differences in shape and pneumatization degree. A higher degree of EMS pneumatization may contribute to the occurrence of CRS; this should be investigated before surgery. [ABSTRACT FROM AUTHOR]