Sinonasal Anatomic Variations According to Frontal Sinus Pneumatization in a Korean Population

Background and Objectives It is necessary to understand the variations of the paranasal sinuses (PNS) and other anatomical structures during an endoscopic sinus surgery (ESS). The purpose of this study was to investigate any association between the degree of frontal sinus (FS) pneumatization and the development of the PNS structures. Subjects and Method We analyzed 311 PNS computed tomography (CT) scans (622 sinuses, including the left and right sides). We classified FS into type I (aplasia), type II (hypoplasia), and type III (control). We assessed and compared the middle turbinate pneumatization (MTP), superior turbinate pneumatization (STP), agger nasi cell (ANC), infraorbital cell (IOC), optic nerve (ON) type, and vidian nerve (VN) type with the pneumatization of the FS. We further studied for any association between the degree of pneumatization of the FS, maxillary sinus (MS), and sphenoid sinus (SS) and the lateral lamella length (LLL). Results MTP, ANC, and IOC rates according to the FS types were not significant (p>0.05). Both type II and III showed more frequent occurrences of STP than type I (p=0.005). The ON type III and IV were significantly frequent in the FS type III (p<0.001). The occurrence of VN type III in the FS type I was significant (p<0.001). When comparing the pneumatizations of FS with MS or SS, there were no significant correlations between them (p>0.05). In the FS type II and III, the LLL was significantly greater than in type I (p<0.001).Conclusion Increased FS pneumatization shows greater indentation of ON and VN into the SS, as well as increased LLL. During ESS, it is important to recognize the possibility of structural damage of ON, VN, and LLL according to FS pneumatization.