An apparatus for bracing a plurality of vertebrae of the human spine has at least two pedicle screws, each having an annular head with an opening therewithin and including a slot therewithin. Each slot extends into the corresponding opening and includes internal threaded portions. A securing screw to...http://www.google.es/patents/US7128743?utm_source=gb-gplus-sharePatente US7128743 - Apparatus for bracing vertebrae
