Background and Objectives: The olfactory fossa is an important anatomical structure to prevent surgical complications such as skull base injury and meningitis. The purpose of this study is to determine if there is a difference in lateral lamella length (LLL) between the left and right sides, a topic that has been studied rarely in Korea. Subjects and Method: We analyzed 592 left and right sides of 296 PNS CTs. We measured LLL as the distance between the fovea ethmoidalis and the horizontal cribriform plate in the olfactory fossa of the coronal surface where the crista galli was observed. Results: The average LLL on the left side was significantly longer than that on the right. Age and LLL showed a negative correlation. Multiple regression analysis revealed younger age and left side as independent variables for predicting increasing LLL. Conclusion There was a significant difference between the two sides of LLL on sinus CT in Koreans. Before sinus surgery, the asymmetry of the ethmoid roof must be assessed, even by skilled doctors. If the height of the ethmoid roof is asymmetric, extra care is required during sinus surgery.

Background and Objectives: The olfactory fossa is an important anatomical structure to prevent surgical complications such as skull base injury and meningitis. The purpose of this study is to determine if there is a difference in lateral lamella length (LLL) between the left and right sides, a topic that has been studied rarely in Korea. Subjects and Method: We analyzed 592 left and right sides of 296 PNS CTs. We measured LLL as the distance between the fovea ethmoidalis and the horizontal cribriform plate in the olfactory fossa of the coronal surface where the crista galli was observed. Results: The average LLL on the left side was significantly longer than that on the right. Age and LLL showed a negative correlation. Multiple regression analysis revealed younger age and left side as independent variables for predicting increasing LLL. Conclusion There was a significant difference between the two sides of LLL on sinus CT in Koreans. Before sinus surgery, the asymmetry of the ethmoid roof must be assessed, even by skilled doctors. If the height of the ethmoid roof is asymmetric, extra care is required during sinus surgery.

Background and Objectives: Obstructive sleep apnea (OSA) is an obstructive airflow disorder that occurs in the upper respiratory tract during sleep and is therefore associated with the occurrence of cardiovascular diseases. By examining the Lund-Mackay (L-M) scores and maxillary sinus mucosal conditions according to the severity of sleep breathing disorder (SBD), we tried to find out the association between SBD and sinus mucosal change.Subjects and Method Of the 189 patients who underwent sinus CT with a polysomnography test, 175 patients were enrolled in our study. We investigated the average L-M score and L-M score of five or higher, and the ratio of maxillary sinus mucosal thickness (MSMT) of 2 mm or higher. Results: The average L-M score of study population was 0.98 points and the L-M score of five or more was found in 14 patients (8%). The MSMT of 2 mm or more was found in 25.5% of the study group. The average L-M scores for the different groups, namely, the simple snoring group, the mild OSA, the moderate OSA, and the severe OSA were 1.31 points, 0.77 points, 0.91 points, and 1.08 points, respectively. There was no significant difference (p=0.736) among them, and there was no correlation between the apnea-hypopnea index score and the L-M score (r=-0.052, p=0.499). There was no significant difference between OSA severity and MSMT (p=0.490). Conclusion There was no significant difference between the L-M score and MSMT depending on the severity of SBD. Therefore, it is believed that SBD will have little effect on the sinus mucosa.

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.

Background and Objectives: It is important to identify variations of paranasal sinuses during sinus surgery. The Onodi cell (OC), a variant of the paranasal sinuses, is the most posterior ethmoid cell with a close relationship with the optic nerve (ON). The purpose of this study is to evaluate the prevalence of OCs and analyze the relationship of OCs with ON in Koreans.Subjects and Method This retrospective study utilized CT images of 526 slides from 263 Korean adults. The prevalence of the OCs and the degree of indentation of the ON within the OC was determined using binary logistic regression analysis. Results: The OCs were observed in 37.3% of 263 subjects and in 27.6% of 526 slides. The OCs are found more frequently in males than in females (p=0.01), and also more frequently in the right side than in the left side (p=0.001). Binary logistic regression analysis revealed that the ON protrusion in female was 0.339 times lower than in male and 1.052 times higher with the increased age. The ON protrusion within the OC in the postsellar type was 10.214 times higher than that in the presellar. Conclusion The OCs were observed in 37.3% of the Koreans. The protrusion of the ON within the OCs increased in male and in the postsellar type of the sphenoid sinus.