Microsurgical anatomy of the pterional approach to the anterior cerebral artery

Objective To study more detailed anatomic data of the anterior cerebral artery (ACA) and its perforating arteries through the pterional approach. Methods Microsurgical anatomy and measurement about ACA and its perforating arteries were performed in both sides of 10 adult red-latex perfused cadaver heads along with the path of the pterional approach under the surgical microscope Results Many anatomical variations were found in A1 segments of ACA. Hypoplasia was common in the right A1 segment and the diameter of the left A1 was bigger than that of the right one. The left-right and anterior-posterior directions of A2 segments were about equal. Most perforating arteries of ACA arose from superior, medial-superior A1 segments and coursed postero- superiorly. A few perforating arteries arose from proximal A1 segments within 3-5 mm and middle 1/3 portion of A1 segments. Conclusion There are many anatomical varitions in A1 segments of ACA and they may be related to the formation of anterior communicating arterial aneurysms. A1 segments should be dissected on their underside and lateral-side, and a temporary clip should be put within their first 3-5 mm or the middle 1/3 portion of A1 segments so that the injury of perforating arteries arising from A1 can be avoided.