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Updated: May 5, 2026
Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms
Published on: August 11, 2015
Anterior clinoidectomy
J Lehmberg1, S M Krieg, B Meyer
1Department of Neurosurgery, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany, jens.lehmberg@lrz.tu-muenchen.de.
Background:
The optic nerve within the optic canal, the parophthalmic segment of the carotid artery, and the oculomotor nerve in the superior orbital fissure all lay against the anterior clinoid process. Bone resection uncovers these structures.
Method:
For extradural resection of the anterior clinoid process and surrounding bone, two key steps are recommended: bony opening of the superior orbital fissure, and transection of the orbitotemporal periosteal fold.
Conclusion:
Anterior clinoidectomy is technically challenging. Following a sequence of surgical steps to expose clearly-defined surgical landmarks helps to make this procedure simple and safe.
Key Points:
• Pterional craniotomy • Complete extradural anterior clinoidectomy • Slit dura (3 mm) to drain cerebrospinal fluid • Peel dura from orbital roof and lateral wall • Bony opening of superior orbital fissure to use it as surgical corridor • Drilling of optic canal • Transection of orbitotemporal periosteal fold • Hollow anterior clinoid process and piece-meal resection • Transection of falciforme ligament to free optic nerve • Replace falciforme ligament by extradural free pericranial flap.
