Lateral orbitotomy without removal of the lateral orbital rim.

Lateral orbitotomy is used for the removal of orbital tumors and for orbital decompression. Most surgeons make saw cuts through the lateral orbital rim and remove and rewire the bone. This procedure is time-consuming and requires repair of the lateral canthal structures. We describe a technique using an air-driven "acorn-tipped" bur that removes the posterolateral lip of the frontal process of the zygomatic bone and effectively straightens the external surface of the lateral orbital wall. This permits removal of the bone without serious injury to the periorbita. The technique creates a trapezoidal orbitotomy measuring approximately 20 mm anteroposterior, 25 mm at the anterior vertical base, and 6 mm at the posterior base. The orbital soft tissues can thus be safely exposed without removal of the lateral rim. We operated on one patient with cavernous hemangioma (27 X 21 X 19 mm) and three patients with bilateral Graves' ophthalmopathy. We discuss anatomic considerations for the prevention of complications, including injury to the frontotemporal branches of the facial nerve, injury to the superior head of the lateral pterygoid muscle, and inadvertent penetration of the dura.