Protrusion of the Infraorbital Nerve into the Maxillary Sinus on CT: Prevalence, Proposed Grading Method, and Suggested Clinical Implications

Abstract

BACKGROUND AND PURPOSE:The infraorbital nerve arises from the maxillary branch of the trigeminal nerve and normally traverses the orbital floor in the infraorbital canal. Sometimes, however, the infraorbital canal protrudes into the maxillary sinus separate from the orbital floor. We systematically studied the prevalence of this variant.

Morphometric evaluation and surgical implications of the infraorbital groove, canal and foramen on cone-beam computed tomography and a review of literature

“…Chandra and Kennedy [16], Elnil et al [23] and Mailleux et al [47] reported cases of IOC passing through in the maxillary sinus. Ference et al [26] reported this variation in 12.5% of 200 cases, Lantos et al [41] reported it in 10.8% of 500 cases and Yenigun et al [79] reported in 12.3% of 750 cases. In the present study, this variation was found to be 7% of 150 cases (Fig.…”

The Prevalence of Protrusion of Infraorbital Nerve into Maxillary Sinus Identified on CT Scan of the Paranasal Sinuses at a Tertiary Hospital in Nepal

“…The protrusion was defined when entire circumference of the inferior orbital nerve was noted within the maxillary sinus without touching the walls. 1 The protrusion was always accompanied with a bony septum. The length of the protruding component along with the bony septum was noted.…”

“…Different classification system has been proposed for this variant. 1,4,7 The definition and classification system for our study was adopted from the paper published by Lantos et al 1 Acgar et al in their study The definition by Lantos et al has specific measurements for classification and easy to follow.…”

“…Protrusion was confirmed with entire circumference of the infraorbital canal along with the infraorbital nerve was noted within the maxillary sinus without touching the walls. 1 The length of the protruding component along with the bony septum was measured on axial images. The variation whether bilateral or unilateral was also noted.…”

“…disease or any tumoral lesion of the paranasal sinuses 1 . CT scan not only provides adequate information regarding the disease process but also identifies normal variants in relation to the paranasal sinuses.…”