Introduction: Fusiform aneurysms of the vertebral artery involving the posterior inferior cerebellar artery (PICA) origin in conjunction with a single anterior spinal artery (ASA) pose a unique challenge to treatment. We propose a treatment paradigm in such cases, depending on the proximity of the aneurysm to the ASA.
Methods: Three cases from our institution are presented. Patient 1 underwent a PICA-PICA bypass followed by endovascular sacrifice of the aneurysm in which the ASA was removed from aneurysm. Patient 2 underwent a PICA-PICA bypass followed by endovascular sacrifice with the aneurysm also removed from ASA. Patient 3 underwent vertebral to PICA bypass followed by aneurysm coiling without vessel sacrifice. The aneurysm expanded to involve the ASA origin, and underwent endovascular occlusion.
Results: We present two cases in which the aneurysm is immediately adjacent to ASA, and one case in which the aneurysm involves ASA. All patients had a single filling ASA on angiography prior to intervention. In the two cases in which the aneurysm is removed from ASA (Patients 1&2), revascularization with vessel sacrifice was successful with good neurologic outcome. In the event the aneurysm involves the ASA origin (Patient 3), revascularization followed by coiling was unsuccessful; the aneurysm grew requiring endovascular occlusion and subsequent medullary infarct.
Conclusions: Vertebral artery aneurysms at the PICA origin associated with a single ASA present a unique challenge to treatment. In cases in which the ASA is removed from the aneurysm, we advocate for revascularization followed by endovascular sacrifice. Aneurysms in which the ASA is associated should undergo flow diversion or primary clip reconstruction to minimize the risk of losing the ASA. Finally, aneurysms immediately adjacent to ASA should undergo revascularization and open trapping to maintain patency of ASA, as the lack of control with endovascular embolization risks ASA occlusion.
Patient Care: By realizing that PICA aneurysms in conjunction with a single ASA pose a unique and challenging paradigm to vascular neurosurgeons, we will be better able to approach and treat these lesions.
Learning Objectives: - To understand the challenges posed by aneurysms of PICA origin with a single ASA
- To understand possible treatment paradigms based on location of PICA aneurysm in conjunction with ASA