Is the measurement of ethmoid sinus dominance in eosinophilic chronic rhinosinusitis accurate?

Objective: An ethmoid-dominant shadow on computed tomography is an indicator of type 2 inflammation, and is one of the main items used to diagnose and classify the severity of eosinophilic chronic rhinosinusitis in the Japanese diagnostic criteria. Ethmoid sinus dominance is examined using the Lund-Mackay scoring system and may be overestimated due to scoring characteristics. We aim to investigate the accuracy of evaluations of ethmoid dominance using the conventional scoring system and the possibility of conducting an objective evaluation using a more detailed other scoring system.
Methods: Patients diagnosed with eosinophilic chronic rhinosinusitis and who underwent bilateral endoscopic sinus surgery were enrolled in the present study. Computed tomography was performed preoperatively on all subjects. The bilateral anterior and posterior ethmoid sinuses and bilateral maxillary sinus were scored, and the ethmoid-to-maxillary ratio was calculated using 3 different scoring systems: Lund-Mackay (each sinus score ranges between 0 and 2), simplified Zinreich (score ranging between 0 and 3), and Zinreich (score ranging between 0 and 5).
Results: A total of 149 patients were eligible for the present study. Significant differences were observed in ethmoid-to-maxillary ratio evaluated by the 3 different scoring systems (2.4 ± 0.7, 3.0 ± 1.1, and 3.7 ± 2.2). Only 2 patients were negative for ethmoid dominance by the Lund-Mackay scoring system, while 14 were negative by the simplified-Zinreich and Zinreich scoring systems. Severity changed from the initial grade in 12 patients.
Conclusions: The present results confirmed a potential overestimation when only the Lund-Mackay scoring system was used to assess ethmoid dominance. Ethmoid dominance has been identified as one of the main predictive factors for the long-term postoperative outcomes of eosinophilic chronic rhinosinusitis and is included in the Japanese diagnostic criteria. A detailed evaluation of ethmoid dominance is desirable for more accurate evaluations of the severity and prognosis of eosinophilic chronic rhinosinusitis.
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