Morphological Evaluation of Infraorbital Canal and its Relation with Surrounding Structures Utilising CBCT: An Observational Study

Abstract

Introduction: Infraorbital nerve is the largest and terminal branch of the maxillary nerve. A lack of knowledge of variations in its course, such as Infraorbital Canal Protrusion (ICP)-which refers to the extension of the nerve from the infraorbital foramen into the maxillary sinus, could lead to iatrogenic injuries during procedures of the maxilla and antrum. Aim: To analyse and determine the morphometric variations of the infraorbital canal and its association with nearby structures utilising Cone Beam Computed Tomography (CBCT). Materials and Methods: A retrospective observational study was conducted in the Department of Oral Medicine and Radiology at Bhimavaram, Andhra Pradesh, India. The data obtained was between November 2019 to May 2023, during which 114 CBCT scans {228 Infra Orbital Canal (IOC)} were analysed retrospectively. IOC was divided into type 1, type 2 and type 3 Measurements taken for type 3 infraorbital canals included the distance from the IOC to the Infraorbital Rim (IOR), the horizontal distance from the IOC to the long axis of the canine, the maximum length of the nerve protruding into the sinus, and the maximum distance from the center of the canal to the roof of the sinus. The association between the types of infraorbital canals and variations in adjacent anatomical structures was evaluated using independent sample t-tests, Fisher’s-exact test, One-way Analysis of Variance (ANOVA), and Pearson’s Chi-square test. Results: Out of 228 IOC types, 78 were classified as type 1, 23 as type 2, and 13 as type 3 on the right side and 73 were type 1 , 36 were type 2, 5 were type 3 on the left-side. Type 1 was higher in number both females and males on both sides, followed by type 2. The mean horizontal distance from IOC to the long axis of the canine {(IOC-Long axis of canine (LCR)} was statistically significant across different types on both the right and left-sides. The prevalence of Haller cells, mucosal thickening, pneumatisation of the middle concha, and maxillary sinus septa was present in 31 (27.19%), 44 (38.6%), 41 (36%), and 29 (25.4%) of the 114 individuals, respectively. Conclusion: A preoperative 3D assessment of IOC is crucial to preventing surgical complications by identifying potential anatomical variations, thereby minimise iatrogenic injuries.

Keywords

• caldwell-luc surgery
• canine fossa
• cone beam computed tomography
• infra-orbital nerve