Opening of unusual vascular collaterals leads to early recanalization of a giant intracavernous carotid artery aneurysm following common carotid artery occlusion: A Case report and literature review

Parent artery occlusion (PAO) with or without bypass surgery is a feasible treatment for large intracavernous carotid artery (ICCA) aneurysms. The ideal occlusion site (internal or common carotid artery [CCA]) and ischemic complications after PAO have received special attention since the description of the technique. Unfrequently, some patients can also develop unusual external carotid artery-internal carotid artery collateral pathways distal to the ligation site that can explain the failure to aneurysm size reduction. We describe a rare case of delayed refilling of a large ICCA aneurysm partially thrombosed which early recanalized after surgical ligation of the cervical CCA through an unusual collateral pathway. Based on our experience, we recommend periodic long-term follow-up neuroimaging, especially in those cases where potential collateral branches have not been clearly identified in the preoperative studies.