Microvascular Clipping of A1 Segment Aneurysms

Aneurysms arising from the proximal segment (A1) of the anterior cerebral artery (ACA) are relatively rare. Because of their small size, abnormal location in relation to the parent artery and the risk of damage to the surrounding perforators, their surgical management is a big challenge. We present our experience with 7 patients of A1 segment aneurysms.

Tertiary care referral center.

Seven patients who were diagnosed with A1 aneurysms between 2009 and 2017 were included. Preoperative evaluation included Non-Contrast Computed Tomography (NCCT) head and angiography (Digital Subtraction Angiography with/without CT-Angiography). The clinicoradiological condition of the patients was graded as per World Federation of Neurological Surgeons (WFNS), Fisher and Hunt and Hess (H and H) Grading systems. A retrospective review of clinical features, radiological descriptions, surgical treatment, and outcomes was done.

All patients underwent microneurosurgical clipping. All aneurysms were saccular, ranging in size from 4 to 14 mm and neck size varied from 2 to10 mm. Most aneurysms 5 (71.4%) had a posterior direction. Anatomical variations were noticed in 3 (42.8%) patients. Posteroinferiorly directed aneurysms were difficult to clip. As per Glasgow Outcome scale (GOS), 6 (85.7%) patients had a good outcome, whereas 1 (14.2%) had poor outcome. As per the modified Rankin Scale (mRS) too, 6 (85.7%) had a favorable outcome. There were no deaths.

A1 aneurysms are frequently associated with vascular anomalies and generally rupture when small. A1 aneurysms with a superior and anterior direction are relatively easy to clip whereas those directed postero-inferiorly are difficult. Close association with critical perforators also compounds the situation. Due to the rarity of A1 aneurysms, large series are few in literature.