Dissection by Oliver Bozinov
Dissection by Pierre-Hugues Roche
Dissection by Pierre-Hugues Roche
Anterior Clinoidectomy Paraclinoid Anatomy
This technique is used for optic nerve decompression, aneurysm surgery is the first step towards cavernous sinus exposure from the superior orbital fissure.
This technique is used for optic nerve decompression, aneurysm surgery is the first step towards cavernous sinus exposure from the superior orbital fissure.
The anterior clinoid process (ACP) has two roots – roof of the optic canal (superior root) and the optic strut (inferior root).
The first step towards extradural anterior clinoidectomy is to unroof the optic canal. This procedure should be performed under constant irrigation in order to avoid thermal damage to the optic nerve.
In the next step of the procedure the anterior clinoid process is hollowed out in order to separate it from the optic strut (inferior root). The optic strut is the inferior part of the optic canal.
After sufficient drilling the ACP is mobilized from its dural attachment and removed.
The first step towards extradural anterior clinoidectomy is to unroof the optic canal. This procedure should be performed under constant irrigation in order to avoid thermal damage to the optic nerve.
In the next step of the procedure the anterior clinoid process is hollowed out in order to separate it from the optic strut (inferior root). The optic strut is the inferior part of the optic canal.
After sufficient drilling the ACP is mobilized from its dural attachment and removed.
Fig. 1. Exposure after right orbitozygomatic craniotomy. The right frontal and temporal lobes are visualized. The orbital roof and the bone over superior orbital fissure (SOF) is drilled away.
Fig. 2. Extradural anterior clinoidectomy – unroofing the optic canal, removal of the superior root of the ACP, is the first step of the procedure. This leads to decompression of the optic nerve.
Fig. 3. Hollowing out the ACP in order to separate it from its inferior root, which is the optic strut.
Fig. 4. Mobilization of the ACP and detachment from the dura.
Fig. 5. The removal of the ACP should be done very carefully in order to avoid injury to the ICA.
Fig. 6. Final view after ACP removal. Note the wide decompression of the optic nerve.
Fig. 7. Intradural exposure. The falciform ligament is cut and the optic nerve is mobilized.
Fig. 8. After mobilization of the optic nerve the ophthalmic artery is exposed arising from the supero-medial pat of the ICA.
Fig. 9. The Llilequist membrane in the optico-carotid window to posterior fossa.
Fig. 10. After the anterior clinoid process is removed the proximal and distal dural rings are visualised.
Fig. 11. Opening of the distal dural ring provides for mobilization of ICA.
Fig. 12. The oculomotor nerve is presented entering oculomotor cistern which is the roof of the cavernous sinus.
Fig. 13. Posterior clinoid process.
Fig. 14. Carotid-oculomotor window to interpeduncular fossa and basilar apex is employed route for clipping basilar artery aneurysms.
Fig. 15. The basilar artery in the interpeduncular fossa.