Tailored Anterior Clinoidectomy: Beyond the Intradural and Extradural Concepts

Abstract

Anterior clinoidectomy (AC) is a key microsurgical step for the safe and successful management of parasellar pathologies that involve the anterior clinoid process (ACP) and the optic canal. Traditionally, extra and intradural ACs are performed separately according to the surgeon's experience or preference. The objective is to present and discuss the tailored AC concept through illustrative cases. We conducted a retrospective record review of three patients who underwent AC as a surgical step for the treatment of parasellar pathologies that involve the ACP and optic canal. A review of the relevant literature on AC was performed in the PubMed, LILACS, and SciELO databases. In all three cases, the pterional craniotomy was the preferred approach for AC. Case 1, a 47-year-old female patient with type III anterior clinoidal meningioma, underwent a tailored intradural technique (optic canal unroofing) with total tumor resection and complete visual recovery. Case 2, a 63-year-old female patient with a complex type II anterior clinoidal meningioma with extensive hyperostosis of the ACP, underwent a hybrid AC technique with complete removal of the tumor and visual improvement. Case 3, a 62-year-old female, underwent a tailored intradural AC for clipping an incidental carotid-ophthalmic aneurysm. Tailored AC aims to provide adequate exposure with less risk of neurovascular injury, allowing enough space to safely treat parasellar lesions. The type, size, and location of the lesion, as well as the surgeon’s experience, should always be considered for surgical planning.

Surgical Anatomy of the Microscopic and Endoscopic Transorbital Approach to the Middle Fossa and Cavernous Sinus: Anatomo-Radiological Study with Clinical Applications

“…The extradural transorbital anterior clinoidectomy has a surgical trajectory along the longitudinal axis of the ACP, allowing a direct view of the opticocarotid region with a short working distance [ 35 , 36 , 37 ]. In the transcranial anterior clinoidectomy, a complete lateral view of the middle cranial fossa is obtained at the expense of potential brain retraction injury and a more invasive procedure [ 58 , 59 ]. However, in TOAs, the reduced maneuverability in the cone-pyramid shape space during the opening the orbital roof and clinoidectomy may damage the ICA, ophthalmic artery, and CN III, making the procedure challenging and risky to perform despite the presence of the dura that protects the intradural structures during the maneuvers [ 35 , 36 , 37 ].…”

The Usefulness of Extradural Anterior Clinoidectomy for Lower-Lying Posterior Communicating Artery Aneurysms : A Cadaveric Study

“…A tailored intradural anterior clinoidectomy is a useful method to obtain a more proximal portion of the ICA to make proximal control precisely. However, it has some risks during the procedure in the case of subarachnoid hemorrhage (SAH) considering unclear surgical field, unstable condition of the aneurysm and so on [ 6 , 26 , 30 ].…”