Andrej von Schilling and Uwe Spetzger, Ph.D. Department of Neurosurgery, Klinikum Karlsruhe, Germany Microsurgical aspects of clipping of a giant partially thrombosed VA aneurysm in a 57-year-old female are presented and explained in the form of a short video. The presentation includes preparation of the VA, PICA and perforating arteries, the clipping of the aneurysm itself as well as the reduction of the aneurysm mass using ultrasonic tissue ablation. In addition pre- and post-operative imaging and superimposed text is used to illustrate the presented anatomy.