The Extended Lateral Supraorbital Approach and Extradural Anterior Clinoidectomy through a Fronto-Pterio-Orbital Window

Objective: To describe a less invasive approach to perform an extradural anterior clinoidectomy (EAC) through a Fronto-pterio-orbital window as a surgical alternative while obtaining access to anterior circulation aneurysms and anterior skull base lesions

Methods: After performing a standard lateral supraorbital craniotomy (LSO). Under the operating microscope, the dura is detached from the orbital roof and the sphenoid wing, that later are thinned off using a 5-mm diamond drill until expose the extradural temporal lobe, superior orbital fissure (SOF) and the meningo-orbital fold (MOF). The bone drilling is performed from the inner frontal aspect through the inside of the craniotomy and without resecting any temporal bone. This opens a “fronto-pterio-orbital” window, exposing the periorbita, and the medial and superior aspect of the temporal lobe extradurally. The SOF is unroofed, and the MOF is cut allowing stripping off the temporal dura from the anterior clinoid process (ACP) and the lateral wall of the cavernous sinus. The ACP is resected extradurally following standard technique. The dura is opened in a longitudinal manner along the Sylvian fissure to the optic nerve sheath, and toward the distal dural ring.

Results: The extended LSO and EAC were used to access four sphenoid wing/anterior clinoidal meningiomas, four anterior circulation aneurysms, two temporomesial lesions, and one orbital/cavernous sinus abscess.

Conclusion: The extended LSO opens a new route (Fronto-pterio-orbital window) to perform safely an EAC and increases the surgical exposure, angles and operability of a less invasive keyhole craniotomy (LSO) to treat anterior cranial fossa lesions.