Management of Orbital Meningiomas and Associated Proptosis

Abstract

Orbital meningiomas are rare, accounting 1–2% of all meningiomas. These tumors may originate from the intraorbital optic shead or from the meningeal layer of the optic canal. The clinical presentation of these tumors is a progressive visual deficit and proptosis. A prompt diagnosis is important to avoid an irreversible no light perception. We include a series of 5 cases with the diagnosis of orbital meningioma which were treated surgically by unroofing the orbit and the optic canal. Initially we present cadaveric pictures detailing the epidural pretemporal approach and the anatomy of the anterior clinoid process. A pterional incision was done followed by a 3 burr hole craniotomy. A epidural dissection and retraction of the frontal and temporal lobes is done using multiple anclated sutures. The sphenoidal lesser wing is exposed and drilled until the periorbit is unroofed. The superior and lateral walls of the orbital apex are removed. The lateral orbital fissure is opened and the foramen rotundum is seen laterally. The orbito meningeal dural layer is exposed, coagulated and incised to expose the complete anterior clinoid process. The 3 osseous structures that give its stability are: the lesser wing, the optic canal and the optic strut. To do an anterior clinoidectomy it is important to disarticulate these bony architecture. When completed the optic canal is unroofed and clinoidal triangle of the cavernous sinus is exposed. This decompression of the optic nerve may improve the visual function in some cases, or avoid its prompt worsening. The removal of the superior and lateral walls of the orbit improves the proptosis and aesthetic. In our series 60% of the patients had visual function previous to the surgery and 40% of the patients improved the visual it after decompression of the optic canal. These results emphasize the importance of a prompt diagnosis and treatment.