A radiological anatomy study of the olfactory sulcus and adjacent structures in Chinese

OBJECTIVE An understanding of the complex anatomy of the anterior skull base is crucial for the surgeon doing endoscopic surgery. The anatomic data of the olfactory sulcus and adjacent structures in Chinese patients were defined using 3-dimensional reconstruction images. The surgeon is encouraged to develop a detailed pre-operative surgical plan by utilizing these dynamic anatomical observations to avoid intracranial injury. METHODS The paranasal sinus CT scanning images of 100 adults were reconstructed for observation using EBW2.0 software and multiplanar reformation. All data obtained were in the coronal plane from the anterior point of the olfactory sulcus. The cribriform plate depth as compared to the ethmoid roof and adjacent structures, was measured bilaterally. Data obtained on adjacent structures include the vertical height of the lateral lamella of olfactory sulcus, the horizontal distance between the cribriform plate and the orbital lamella, the length of the middle turbinate, the height of the orbit, and the vertical distance between the cribriform plate and the nasal floor. RESULTS The olfactory sulcus was classified into three types: platform type (60 %), sloping type (17 %) and mixed type(23 %), as distinguished from Keros classification. In this study the vertical height of the lateral lamella of olfactory sulcus was (5.03 ± 0.17) mm (R) and (5.39 ± 0.19) mm (L) in platform type, and (2.79 ± 0.49) mm (R) and (4.72 ± 0.49) mm (L) in the mixed type. There were statistically significant differences between the right side and the left side in these two types (P0.01). The horizontal distance between the cribriform plate and the orbital lamella on the same side was significantly different between the platform type and the mixed type of olfactory sulcus. A similar result was observed for the vertical distance between the cribriform plate and the nasal floor. Gender differences exist in the horizontal distance between the cribriform plate and orbital lamella on the same side and the vertical distance between the cribriform plate and the nasal floor. CONCLUSION Different types of olfactory sulcus have distinct characteristics, hence care which must be taken into account when doing endoscopic surgery.