Novel classification and microsurgical anatomy of the basilar artery: a cadaveric study

Purpose: The trunk of the BA remains underrepresented in microsurgical studies. This study aims to address this gap by providing a detailed review of the BA’s microsurgical anatomy, proposing a novel segmental classification of the artery and the significance of each segment in various surgical pathologies and approaches. Methods: A total of 20 cadaveric adult brain specimens were meticulously examined under high magnification, following Institutional Review Board approval. The dissection focused on the BA and its branches, with morphometric data collected, including dimensions and anatomical variations. Results: This study included 20 specimens. A novel classification was proposed base on the blood flow direction, including three segments. The inferior segment extended from the junction of the VA to the origin of the most rostral collateral artery, averaging 3.55 mm in diameter and lengths between 9.0 and 17.1 mm, with 3 to 4 caudal perforators. The middle segment, which ranged from the inferior border of the anterior inferior cerebellar artery (AICA) to the origin of the superior cerebellar artery, measured 3.44 mm in diameter and 15.2 mm in length, featuring 5–6 middle perforating branches. The superior segment ended at the bifurcation of the BA, with an average diameter of 4.2 mm and a length of 3.6 mm. The overall BA length averaged 30.7 mm, with a range of 23.5–38.2 mm. Conclusion: A comprehensive understanding of the origin, course, branches and segments of the BA is crucial for mitigating vascular complications during both open and endovascular surgical procedures.