Endoscopic Anatomy Research Related to Transsphenoidal Optic Nerve Decompression

Objective To investigate the anatomical relationship among optic nerve, posterior ethmoid sinus and ophthalmic artery to further provide surgical instruction for endoscopic transsphenoidal optic nerve decompression. Method Messerklinger technique was adopted in eight cases of adult cadaveric head to expose the posterior ethmoid sinus and sphenoid sinus. The optic-carotid recess and optic canal were identified. The adjacent structure of optic canal was observed. After removal of the bony wall of optic canal, the relationship between the optic nerve and the ophthalmic artery was disrupted. Result the optic-carotid recess was observed in all specimens. The occurrence of optic nerve prominence was 62%. Three patterns of the syntropy of optic nerve were observed. Optic nerve was border by posterior ethmoid sinus anteriorly and sphenoid sinus posteriorly in 8 cases (50%), by sphenoid sinus in 5 (31%), and by posterior ethmoid sinus in 3 (19%). At the cranial end, The ophthalmic artery was observed, 9 (56%) inferior-medially, 4 (25%) inferiorly and 3 (19%) inferior-laterally relative to optic nerve. At the ophthalmic end, the artery was observed 3 (19%) inferiorly and 13 (81%) inferior-laterally relative to optic nerve. Conclusion The optic-carotid recess can be regarded as the first landmark. The ophthalmic artery injury should be avoided with regard to its relationship with optic nerve during endoscopic decompression surgery.