Endoscopic transorbital transconjunctival approach to the pterygopalatine fossa: anatomical cadaver study

This study aimed to provide an anatomical description of the endoscopic transorbital (ETO) transconjunctival approach to the pterygopalatine fossa (PPF).

Five formalin-fixed, silicone-injected human cadaver heads were studied at the Rhoton Anatomy Laboratory, Bahçeşehir University Faculty of Medicine, Istanbul, Turkey. By using the ETO transconjunctival route, the authors performed dissections on 10 PPFs (both orbits of each specimen). A 0° Olympus endoscope, along with a fiberoptic system, light source, camera, and digital video recording, was used for documentation.

The procedure consisted of three main stages. 1) In the orbital conjunctival stage, a transconjunctival incision was made in the infraorbital region, followed by posterior subperiosteal dissection. 2) In the orbitomaxillary stage, osteotomy of the infraorbital floor was performed using posterior compression, exposing the orbitomaxillary segment of the infraorbital nerve (ION) and providing access to the maxillary sinus. 3) In the pterygopalatine stage, removal of the posterior maxillary wall allowed visualization of the PPF. The pterygopalatine segment of the ION and other regional structures were identified. The mean ± SD distance from the inferior orbital rim to the distal infraorbital canal was 21.8 ± 1.6 mm. The trajectory of the ION and maxillary branch of the trigeminal nerve (CN V2) to the foramen rotundum was mean ± SD 47.3 ± 4.4 mm. The minimal amount of posterior maxillary wall removed to access the ION-to-CN V2 transition measured 12.7 ± 3.5 mm vertically and 11.9 ± 1.5 mm horizontally.

The ETO transconjunctival approach offers a viable alternative for accessing the PPF in selected cases, with potential benefits of reduced complication risk and a more straightforward approach compared to other methods. Further anatomical studies are warranted due to limited existing data.