Radiographic and microsurgical characteristics of proximal (A1) segment aneurysms of the anterior cerebral artery

• Published in: Neurological sciences 2018-10, Vol.39 (10), p.1735-1740
• Main Authors: Jang, Chang Ki, Jang, E-Wook, Cho, Kwang-Chun, Suh, Sang Hyun, Chung, Joonho, Kim, Yong Bae, Hong, Chang-Ki, Joo, Jin-Yang
• Format: Article
• Language: English
• Subjects: Adult; Aneurysm; Aneurysm, Ruptured - diagnostic imaging; Aneurysm, Ruptured - surgery; Aneurysms; Anterior Cerebral Artery - diagnostic imaging; Anterior Cerebral Artery - surgery; Carotid artery; Cerebral Angiography; Cerebral Arterial Diseases - diagnostic imaging; Cerebral Arterial Diseases - surgery; Female; Humans; Intracranial Aneurysm - diagnostic imaging; Intracranial Aneurysm - surgery; Male; Medicine; Medicine & Public Health; Microsurgery; Middle Aged; Morbidity; Neurology; Neuroradiology; Neurosciences; Neurosurgery; Neurosurgical Procedures; Original Article; Psychiatry; Retrospective Studies; Veins & arteries
• ISSN: 1590-1874; 1590-3478
• DOI: 10.1007/s10072-018-3492-1

Background Proximal A1 segment aneurysms of the anterior cerebral artery (ACA) radiologically resemble internal carotid artery bifurcation (ICBIF) aneurysms because of their anatomical proximity. However, proximal A1 aneurysms exhibit distinguishing features, relative to ICBIF aneurysms. We report our experience of managing proximal A1 aneurysms, then compare them to ICBIF aneurysms. Methods Among 2191 aneurysms treated between 2000 and 2016 in a single institution, we retrospectively reviewed 100 cases categorized as ICBIF or A1 aneurysms. We included aneurysms originating from the ICBIF and ACA, proximal to the anterior communicating artery (A1 segment) and divided them into two groups: proximal A1 ( n  = 32) and ICBIF ( n  = 50). If any portion of the aneurysm involved the ICBIF, it was classified as ICBIF. Aneurysms wholly located in the A1 segment were classified as proximal A1. Patient factors and angiographic factors were evaluated and compared. Results The proximal A1 group exhibited differences in aneurysm size ( p  = 0.013), posterior aneurysm direction ( p  = 0.001), and A1 perforators as incorporating vessels ( p  = 0.001). The proximal A1 group tended to rupture more frequently when the aneurysm was smaller ( p  = 0.046). One case of morbidity occurred in the proximal A1 group. Conclusion Compared to ICBIF aneurysms, proximal A1 aneurysms were smaller and directed posteriorly, with incorporating perforators. Because of these characteristics, it may be difficult to perform clipping with 360° view in microsurgical field. Therefore, when planning to treat proximal A1 aneurysms, different treatment strategies may be necessary, relative to those used for ICBIF aneurysms.