ION and its canal are important landmarks during surgical approaches to the orbital floor and pterygopalatine fossa. Researchers did this study to investigate the infraorbital canal’s anatomic variants from a pre-lacrimal endoscopic perspective and to explore the impact of these variants on exposing the lateral orbital floor.

Ten cadaveric specimens were dissected through an endonasal pre-lacrimal approach. The researchers also investigated the need for ION transposition to increase the exposure of the lateral orbital floor.

Although analysis could directly assess the orbital floor in Type 1 and Type 3 IONs, the ION transposition was necessary to expose the lateral orbital floor in 5 of 12 sides for Type 2 ION. Researchers identified the orbital floor’s bony dehiscence in 8 of 20 sides and the ION branch in 2 of 20 sides.

The study concluded that anatomic variations of the infraorbital canal impact surgical exposure of the orbital floor via a pre-lacrimal approach. Type 1 and Type 3 ION variants allow direct exposure of the entire orbital floor. A Type 2 ION may require transposition of the nerve to expose the lateral orbital floor adequately.