A fusion cage 10 includes a cage body defining an internal cavity with an inner surface and an outer surface. The outer surface defines a helical thread 12 comprised of a plurality of turns which define valleys 14 therebetween. Located in the valleys 14 are perforations 13 which provide communication...http://www.google.de/patents/US4961740?utm_source=gb-gplus-sharePatent US4961740 - V-thread fusion cage and method of fusing a bone joint
