Abstract:ObjectiveTo explore the feasibility of hierarchic ethmoidectomy by analyzing ethmoidal sinus lamella hierarchical structures.MethodsThe original digital imaging and communications in medicine (DICOM) data of sinus computer tomography (CT) were collected. Slice thickness and interval distance were both 0.65mm. Threedimensional (3D) reconstruction of ethmoidal sinus and lamellae (IIIV) hierarchical structures as well as their pneumatization were performed with ImageViewer software.ResultsCT DICOM data from 100 cases (200 sides) were collected and reconstructed for 3D analysis. The ethmoidal sinuses were composed with lamellae IV and lamella V was presented in 60% of the cases. Potential hierarchical spaces existed between the lamellae. The occurrence rate of Haller’s cell was 28.0% , and they were pneumatilazed from the lamella of middle turbinate (19.5%) or the superior turbinate (8.5%), respectively. The pneumatization rate of the superior turbinate and its lamella was 91.5%, and 19.1% of them were pneumatilazed to Onodi cells. The supreme nasal turbinate and its lamella was presented in 60% of the sinuses with a pneumatilization rate of 76.7%, and 15.8% of them were pneumatilized to Onodi cells. The occurrence rate of Onodi cells was 33%, and the cells were originated from the lamellae of superior turbinate (17.5%), supreme nasal turbinate (9.5%), or both (6.0%), respectively. The lamellae and their corresponding pneumatilized structures composed a relatively independent air flow and drainage system and could cause local disorders by themselves. In ethmoidal sinus surgery, the superior and supreme turbinates could be the landmarks for safe endoscopic ethmoidectomy. The III and IV lamellae and their corresponding pneumatilized cells could be completely removed just in the front of the superior and supreme turbinates, respectively. The V lamella and corresponding pneumatilized cells also could be safely and precisely removed according to the landmark of supreme turbinate demonstrated by CT scan.ConclusionAnalysis of the hierarchical lamella structures may have important significance to perform the hierarchical and standard endoscopic ethmoidectomy.