Computed tomography evaluation of the morphometry and variations of the infraorbital canal concerning endoscopic surgery

Publication date: Available online 8 September 2017
Source:Brazilian Journal of Otorhinolaryngology
Author(s): Gülay Açar, Kemal Emre Özen, İbrahim Güler, Mustafa Büyükmumcu
IntroductionThe course of the infraorbital canal may leave the infraorbital nerve susceptible to injury during reconstructive and endoscopic surgery manipulating the roof of the maxillary sinus.ObjectiveWe investigated both the morphometry and variations of the infraorbital canal and aimed to show the relationship between them concerning endoscopic approaches.MethodsThis retrospective study was performed on paranasal multidetector computed tomography images of 200 patients.ResultsThe infraorbital canal corpus types were categorized as Type 1; within the maxillary bony roof (55.3%), Type 2; partially protruding into maxillary sinus (26.7%), Type 3; within the maxillary sinus (9.5%), Type 4; located anatomically at the outer limit of the zygomatic recess of the maxillary bone (8.5%). The internal angulation and the length of the infraorbital canal, the infraorbital foramen entry angles and the distances related to the infraorbital foramen localization were measured and their relationships with the infraorbital canal variations were analyzed. We reported that the internal angulations in both of sagittal and axial sections mostly found in infraorbital canal Type 1 and 4 (69.2%, 64.7%) but, there was commonly no angulation in Type 3 (68.4%) (p<0.001). The length of the infraorbital canal and the distances from the infraorbital foramen to the infraorbital rim and piriform aperture was measured as the longest in Type 3 and the smallest in Type 1 (p<0.001). The sagittal infraorbital foramen entry angles were detected significantly smaller in Type 3 and larger in Type 1 than that in other types (p=0.003). The maxillary sinus septa and the Haller cell were observed in 28% and 16% of the images, respectively.ConclusionPrecise knowledge of the infraorbital canal corpus types and relationship with the morphometry allow surgeon to choose an appropriate surgical approach to avoid iatrogenic infraorbital nerve injury.



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