Evaluation of Protrusion of Infraorbital Canal into the Maxillary Sinus on Cone-Beam Computed Tomography Scans: A Retrospective Study

Background: Projection of the infraorbital nerve (ION) into the maxillary sinus may predispose an individual to iatrogenic problems like paresthesia, hypesthesia, and/or lifelong discomfort because of nerve infringement. Therefore, a detailed radiological evaluation of possible nerve protrusion is vital before planning an endoscopic or open sinus operation. Objective: To evaluate protrusion of the infraorbital canal (IOC) into the maxillary sinus on cone-beam computed tomography (CBCT) scans. Methods: About 500 CBCT scans were evaluated retrospectively for 1000 maxillary air sinuses. The incidence of unilateral and bilateral protrusion of the IOC into the maxillary sinus was noted along with the length of protrusion on axial view. The protrusion was further classified into three categories based on the classification given by Ference et al . Descriptive analysis was done. Results: The prevalence of protrusion of the inferior orbital nerve in our study was 13.40% and bilateral protrusion was 10.8%. The median of the length of the protruding portion with the septum length was 8.5 mm. Conclusion: A CBCT scan must be advised to every patient undergoing maxillary sinus surgery to rule out the possibility of IOC protrusion, as this is a prevalent finding in the Indian population.