Endoscopic transsphenoidal optic nerve decompression: an anatomical study

Area of Science:

• Neurosurgery
• Anatomy
• Endoscopic Surgery

Background:

• The endoscopic transsphenoidal approach is a viable option for accessing the sellar region.
• Limited data exist on the effectiveness and required extent of optic nerve decompression using this technique.

Purpose of the Study:

• To describe key anatomical landmarks for the endoscopic transsphenoidal approach to the optic nerve.
• To evaluate the feasibility and safety of optic nerve decompression via this approach.

Main Methods:

• Dissection of six silicone-injected cadaver heads using the endoscopic transnasal approach.
• Bilateral optic nerve decompression, identification of the lateral optocarotid recess (OCR) and optic canal.
• Examination of the relationship between the ophthalmic artery origin and the optic nerve.

Main Results:

• Twelve optic nerve decompressions were performed.
• Measurements included intercarotid distance (12 mm ± 1.5), OCR length (5 mm ± 1), and optic nerve decompression length (15 mm ± 2).
• Ophthalmic artery origin relative to the internal carotid artery varied (medial, ventral, lateral).

Conclusions:

• The transsphenoidal approach enables extensive optic nerve decompression.
• The intimate relationship between the optic nerve and ophthalmic artery increases injury risk compared to supratentorial approaches.
• Understanding anatomical landmarks, including the lateral OCR and ophthalmic artery position, is vital for preventing injury.