Accurate Localization of Aneurysm Neck Margins in Clipping of a Carotid Cave Aneurysm Using Intraoperative Dual-Volume 3-Dimensional Volume-Rendering Rotational Angiography.

Background: Full visualization of the aneurysm neck is usually impossible in a classical pterional craniotomy when a paraclinoid aneurysm is located on the opposite side of the internal carotid artery. Optic nerve (ON) retraction is required for better aneurysmal exposure, but ON injuries may occur.

Clinical Description: In a case of a 70-year-old female harboring a carotid cave aneurysm, we introduced a new method to delineate better the margins of the aneurysm neck by using intraoperative 3-dimensional (3D) rotational angiography (RA) with dual-volume reconstruction. After complete exposure of the aneurysm, we placed a straight clip adjacent to the aneurysm for localization purposes and performed 3D-RA to locate the distal end of the aneurysm neck relative to the localization clip. With a better anatomic understanding of the neck position, we were able to reduce ON retraction and position the clip across the aneurysm neck more precisely.

Conclusions: With the advantage of a hybrid operating room, we introduced a novel technique to define the margins of the obscured aneurysm neck more clearly by obtaining a 3D-RA dual-volume reconstruction image to locate the aneurysm neck relative to a localization clip. This technique facilitates the clipping procedure and also reduces the risk related to ON retraction during surgical exposure of a paraclinoid aneurysm.