Anatomic evaluation of endoscopic transnasal transorbital approach to the lateral orbital apex

Background: This anatomic study investigates the feasibility of an endoscopic transnasal transorbital approach to the lateral orbital apex. Methods: Five cadavers with no prior history of sinus surgery were studied bilaterally. Standard techniques and instrumentation for functional endoscopic sinus surgery were used to perform dissections and delineate anatomy of sinuses and orbits. Results: With resection of the inferior aspect of the lamina papyracea and the medial portion of the orbital floor, followed by incision of the periorbita along the inferomedial aspect of the orbit and removal of minimal orbital fat, a satisfactory view of the surgical field is achieved. The medial and inferior rectus muscles are dissected and retracted to allow visualization of the optic nerve. By dissecting inferior to the optic nerve and using 0 and 30 degrees endoscopes, the lateral orbital apex could be accessed without damage to the optic nerve. Conclusion: In patients whose vision is irreparably damaged, one might consider an endoscopic approach to lesions of the lateral orbital apex. Approach in patients with intact vision should be handled with caution because of possible traction of the optic nerve.