Supraorbital vs Endo-Orbital Routes to the Lateral Skull Base: A Quantitative and Qualitative Anatomic Study

Area of Science:

• Neurosurgery
• Surgical Anatomy
• Minimally Invasive Techniques

Background:

• Traditional supraorbital approaches access lateral and parasellar middle cranial fossa regions by removing orbital rim and sphenoid wings.
• Emerging endoscopic ventral transorbital pathways necessitate comparison with established transcranial windows.

Purpose of the Study:

• To anatomically detail and quantify surgical exposures in the lateral and parasellar middle cranial fossa.
• To compare the efficacy of transcranial versus transorbital surgical windows.

Main Methods:

• Cadaveric dissection of 5 specimens (10 sides) using supraorbital and endoscopic endo-orbital approaches.
• Quantification of operative working areas in Sylvian, anterolateral temporal, and parasellar regions.
• Measurement of bone removal volumes for each surgical stage.

Main Results:

• Both eyelid (transorbital) and transcranial routes provided comparable visualization of anterolateral temporal and Sylvian areas.
• The transorbital approach significantly enhanced parasellar region exposure and angle of attack compared to transcranial supraorbital views (P < .01).
• Bone removal volumes were comparable between the two approaches.

Conclusions:

• The endoscopic transorbital approach provides a unique view of the lateral and parasellar middle cranial fossa.
• This ventral route may offer new surgical applications for pathologies typically addressed via transcranial approaches.
• Potential challenges include surgeon unfamiliarity with the anatomy and difficulties in dural/orbital repair.