Anterior clinoidectomy



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.


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.


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

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Conflicts of interest


Author information

Correspondence to J. Lehmberg.

Additional information


Anterior clinoid Process (ACP) resection is a regular and mini-invasive skull base procedure that offers an optimal corridor for the exposure of a large range of aneurysms and skull base tumors. Such a technique should be part of the regular learning of each neurosurgeon. That is the reason why contributions that promote simplified and safest techniques are very welcome. For aneurysmal surgery there is still a controversy in the selection of an intradural or an extradural resection, while the extradural approach is dedicated to the resection of parasellar tumors, as pioneered by Dolenc.

Pierre-Hugues Roche

Marseille, France

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Lehmberg, J., Krieg, S.M. & Meyer, B. Anterior clinoidectomy. Acta Neurochir 156, 415–419 (2014).

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  • Skull base surgery
  • Cerebrovascular surgery