After carrying out the first free vein graft transplantation on an aneurysm of the axillary vein by Lexer in 1907, many attempts were made to reconstruct arterial injuries with direct vascular suture technique or vein graft transplants during the Balkan War (1912) and the First World War (1914-1918). Hans von Haberer gained wide experience in the reconstructive surgery of traumatic aneurysms at the Department of Surgery at the University of Innsbruck. During this period, he operated on a total of 201 vascular aneurysms, mainly using a direct circular vascular suture technique. In 1914, von Haberer described the first reconstruction of a carotid aneurysm. First experiences with vein bypasses were made, but not pursued in the following years.