Threaded fusion cage with enhanced anterior support

摘要

A threaded fusion cage for implantation between a pair of vertebrae. The cage has a discontinuous thread helically wound thereabout. The thread has a constant depth in posterior and middle portions of the cage but is feathered in an anterior portion of the cage so that the minor radius approaches or equals the major radius of the thread. This provides greater support to the relatively stronger and harder bone found at the anterior end of the vertebrae.