Covered stent deployment for a recurrent cervical internal carotid artery aneurysm referencing angioscopy: illustrative case.

Background: Extracranial carotid artery aneurysms (ECAAs) are rare, and treatment guidelines are lacking. Few reports on endovascular treatments performed for ECAAs exist.
Observations: A 73-year-old woman with a left giant cervical internal carotid artery aneurysm was treated with overlapping closed-cell stents. The aneurysm regrew 1 year after the treatment, and then a covered stent was deployed. Angioscopy was performed to confirm neointimal development to determine the appropriate stent position before the retreatment, and it revealed that the stent struts were embedded in thick neointima for the most part but that the neointima was thin around the aneurysm neck. Multiple holes connecting to the aneurysm were observed between the stent struts. A covered stent overlapped inside the closed-cell stents, and blood flow into the aneurysm completely disappeared.
Lessons: When deploying the covered stent for recurrent aneurysms, angioscopy is useful for confirming neointimal development and determining the appropriate stent length and position. Angioscopic observations suggest that using stents with a higher mesh density and smaller pore size can reduce the neck hole size of the aneurysm and may achieve complete occlusion of the aneurysm. https://thejns.org/doi/10.3171/CASE24383.