Vascularization of the Subthalamic Nucleus: Highlighting the Significance of the Premamillary Artery

BACKGROUND: The need for a better understanding of the subthalamic nucleus (STN)'s vascular anatomy is still evident because revealing its vascular supply may increase insight in the pathogenesis of related disorders, such as STN ischemia. The mechanisms under motor, behavioral, and cognitive changes following deep brain stimulation treatment may also be explained by its pattern of vascularization. The primary goal of this study was to delineate the vascularization of the STN and highlight the predominant perforating arteries supplying its territory. METHODS: Fiber dissections were performed with the modified Klingler technique under 6-40x magnification by preserving all vascular structures. RESULTS: The thalamic and subthalamic regions were dissected from medial to lateral in silicone-injected cadavers. The STN was revealed as a biconvex-shaped structure surrounded by dense inferolateral bundles of myelinated fibers, the zona incerta, bordering the superolateral portion of the red nucleus. The ventral limit of the STN was the substantia nigra, and the internal capsule traversed from its inferior to anterolateral side. The premamillary artery, a large perforator arising from the posterior communicating artery, constantly supplied the STN and was followed proximally along the anterior third ventricular floor toward its origin. The premamillary artery was found to be one of the posterior perforators of the posterior communicating artery in all hemispheres. CONCLUSIONS: The 3-dimensional microsurgical anatomy of the deep-seated STN region is complex, and the additional knowledge on its vascularization should improve our understanding of its surgical anatomy.