Fusiform vertebral artery aneurysms involving the posterior inferior cerebellar artery origin associated with the sole angiographic anterior spinal artery origin: technical case report and treatment paradigm proposal

Abstract

Fusiform aneurysms of the vertebral artery (VA) involving the posterior inferior cerebellar artery (PICA) origin are uncommon and challenging. The anterior spinal artery (ASA) commonly originates from a unilateral ramus just distal to the PICA. Occlusion of an unpaired ASA can result in bilateral medial medullary syndrome. The authors propose a treatment paradigm for ASA preservation based on the artery’s proximity to fusiform VA aneurysms, and they present 3 representative cases. In the first case, they performed a V3-PICA bypass using an interposition graft and then performed endovascular coil embolization of the parent VA. A complete occlusion of the aneurysm and VA was complicated by ASA thrombosis. The subsequent cases were treated with PICA-PICA bypass and subsequent endovascular embolization of the VA. Filling of the sole angiographic ASA remote from the aneurysm was preserved in both cases. The anatomy of the ASA is the most critical determinant of treatment recommendations for fusiform VA aneurysms involving PICA. When the ASA originates from the aneurysm, proximal occlusion with or without a PICA bypass is suggested. In cases in which the ASA is removed from the aneurysm, the authors recommend revascularization followed by endovascular sacrifice. When the aneurysm is immediately adjacent to the ASA, revascularization and open trapping should be considered.

Role of the Cervical Anterior Spinal Artery in the Endovascular Treatment of Vascular Diseases: Bystander, Accomplice, Victim, or Friend?

“…The typical ASA originates as a common trunk from paired VAs, and its origin is 5–17 mm proximal to the vertebrobasilar junction, angiographically presenting with a characteristic midline hairpin ( 5 , 9 , 10 ). High anatomical variability of the ASA origin exists, and it often has either a predominance of one ramus over the other or a sole unilateral ramus of origin ( 11 , 12 ). The Santos-Franco et al study reported a less typical bilateral origin of the ASA ( 13 ).…”

“…The metal coverage of conventional intracranial stents is low; with their assistance, coiling for VA aneurysms is safe for the ASA ( Figure 5 ) ( 97 ). However, when the ASA originates from the aneurysm, coiling with sacrifice of the ASA should be conducted with caution ( 11 ). If the collateral circulation is insufficient, occlusion of an unpaired ASA can result in bilateral medial medullary syndrome ( 11 , 98 , 99 ).…”

“…However, when the ASA originates from the aneurysm, coiling with sacrifice of the ASA should be conducted with caution ( 11 ). If the collateral circulation is insufficient, occlusion of an unpaired ASA can result in bilateral medial medullary syndrome ( 11 , 98 , 99 ).…”

“…The study showed that the risk was not the length but the anatomical location of VA trapping; therefore, preservation of the ASA origin can reduce the risk of medullary infarction ( 100 ). In addition, it is worth noting that, sometimes, despite preserved flow of the ASA, spinal cord hemodynamic infarction can occur due to hypoperfusion ( 11 ).…”

“…Considering the potential risk factor, FD deployment should likely be avoided in cases of an unpaired ASA, and FD with coverage of the sole ASA is likely not a favorable treatment option ( 11 ). In cases of paired ASAs, FD use could be more liberal; however, FD deployment in bilateral VAs necessitates more caution ( Figure 6 ).…”