Abstract
This study aimed to investigate the incidence of infraorbital canal (IOC) protrusion into the maxillary sinus via computed tomography (CT) and classify its variations. Additionally, it sought to identify nearby sinonasal variations that might elevate the risk of iatrogenic injury. Paranasal sinus CT of 500 patients was evaluated retrospectively. The IOC types were categorized. The length of the IOC, septum, the distance between the maxillary ostium and IOC (dOI), the presence of Haller cells, IOC-related intra-sinus opacity, and IOC dehiscence were investigated. The prevalence of type 3 IOC was 12%, of which 9.2% were type 3c. The maximum length of the IOC was positively correlated with type 3 IOC. A significant difference was found between IOC types in terms of dOI only on the left side. On both sides, the incidence of Haller cells was greater in patients with type 2 IOC than in those with type 1 and in patients with type 3 IOC than in those with type 2. IOC-related opacity and IOC dehiscence were more common in types 2 and 3 IOCs. The assessment of preoperative IOC types and neighboring anatomical structures by CT imaging is of great significance in preventing iatrogenic damage.