Endoscopic Endonasal Approach to the Orbit: an Anatomical and Clinical Study

Background: Recently, many Authors have reported the application of the endoscopic endonasal approach for intraorbital intraconic lesions located in the medial retrobulbar space and in the orbital apex medial to optic nerve. In few anatomical regions the knowledge of anatomy is so relevant to orientate and guide the surgeon and at present, no descriptions of the orbit anatomy from the endoscopic endonasal perspective have reported.

Objective: Investigate the anatomy of this highly complex region from the endoscopic endonasal point of view, and to illustrate in clinical cases the advantages and limits of this approach in comparison to the traditional transcranial route for selected intraorbital intraconic lesions.

Materials and Methods: Anatomical dissection of 10 orbits has been performed in 5 fixed and injected cadaveric specimens with both endoscopic endonasal and transcranial approach.

Results: In all specimens the endoscopic endonasal approach allows us to identify all the anatomical (vascular, nervous and muscular) structures medially to the optic nerve and to obtain a good exposure of the orbital apex and of its content. Even if this region is still accessible throughout a transcranial route, the endoscopic endonasal approach gives a direct and straightforward vision.

Conclusion: The endoscopic endonasal approach is feasible and safe for selected intraorbital intraconic lesions. It gives a wide access to the medial compartments of the retrobulbar space, and allows a good visualization and control of the main vascular and nervous structures