Supraorbital Keyhole Craniotomy for Basilar Artery Aneurysms: Accounting for the “Cliff” Effect

Abstract

The orbital roof-dorsum line provides a simple and reliable method of estimating basilar artery exposure and should be used whenever considering patients for surgical clipping by this approach.

Keyhole clipping of a low-lying basilar apex aneurysm without posterior clinoidectomy utilizing endoscopic indocyanine green video angiography

“…In this case, we were able to estimate the amount of BX exposure we would achieve with a supraorbital approach. [31] is estimation was confirmed intraoperatively and, as predicted, visualization of the BA beyond the aneurysm neck was not adequate under the microscope. Using an endoscope allowed substantially increased visualization that obviated the need to perform a posterior clinoidectomy.…”

“…e MCA bifurcation aneurysm was noted to be at the level of the lesser wing of the sphenoid bone and evaluation of the anatomical accessibility of the BX aneurysm was determined using the orbital roof-dorsum estimation line as previously described. [31] Briefly, the elevation of the orbital roof off the anterior skull base is determined in the coronal plane which is then translated on to the midsagittal plane; this point is then extended to the top of the posterior clinoid and continuing until it reaches the basilar artery (BA) determining the most superior exposure of the BA. Utilizing this line, it was estimated that the superior most exposure through the SOKA would be the neck of the aneurysm with further inferior exposure afforded by the superior extent of the craniotomy off the roof of the orbit [ Figure 2].…”