Endoscopic approaches to the orbit: a cadaveric study.

INTRODUCTION: The role of the endoscopic management of lesions located in the anterior cranial fossa and skull base continues to expand.
MATERIALS AND METHODS: An endoscopic anatomic study was conducted on cadaver specimens. 10 orbits from 5 cadaveric heads fixed in formalin were examined after the vascular structures had been perfused with colored latex and silicone. Endoscopic dissections were performed using rigid endoscopes of 4 mm diameter, 18 cm length, and equipped with 0 degrees , and 30 degrees lenses, according to the different steps of the anatomic dissection protocol.
RESULTS: We have identified and described three endoscopic approaches to the orbit: 1) an inferolateral endoscopic orbital approach (IL-EOA), 2) an endoscopic endonasal medial orbital approach (EEM-OA), and 3) a transcranial key hole endoscopic orbital approach (TCK-EOA). DISCUSSION: The IL-EOA provides excellent exposure of the temporal compartment of the orbit. In this approach special care should be taken to preserve the ciliary ganglion, the ciliary artery and the ciliary nerves. The EEM-OA offers direct access to the medial and inferomedial orbit, the medial part of the optic nerve and orbital apex through its anteromedial walls. The EEM-OA is simple, relatively quick and has superiority over microsurgical operations by excluding the potential complications of intracranial operations. The EEM-OA is minimally invasive and cosmetically acceptable. The TCK-EOA offers an exposure of the orbital roof and the superior part of the optic nerve as well as other intraorbital structures from above. The TCK-EOA is a potentially safe approach for tumors extending from the orbital wall to the anterior cranial fossa and the parasellar region. Copyright Georg Thieme Verlag KG Stuttgart. New York.