Aneurysms of The Middle Cerebral Artery Proximal Segment (M1) · Anatomical and Therapeutic Considerations · Revision of A Series. Analysis of a series of the pre bifurcation segment aneurysms

Aneurysms of the middle cerebral artery represent almost a third of all the aneurysms of the circle of Willis anterior sector. Among them, those located at its so-called M1 segment (from its origin up to the bifurcation) range between 2% and 7% of all the aneurysms. It is highly important to know the anatomy of the M1 segment, as well as of the arterial branches that arise from it, since causing its damage during dissection or occlusion of an aneurysm may determine the neurological sequelae. The authors of the present work, based on a recent anatomical analysis carried out by one of them (FM), have performed a study of the aneurysms of the M1 segment in a series of 1059 aneurysms treated with surgery along 25 years. At the mentioned location 23 aneurysms were found, which represented 2.2% of the total operated aneurysms. The cases, location of the aneurysms and their relation with the early branches of the middle cerebral artery were studied, as well as the surgical difficulties that they pose. A review of the scanty bibliography referring specifically to the aneurysms in this topography has been carried out.