A surgical method and apparatus for accurately aligning the trajectory of, guiding of, and introducing or withdrawal of an instrument is disclosed. The apparatus includes a base which has a movable member movably attached to the base. The movable member has a passage therein which forms a portion of...http://www.google.fr/patents/US5993463?utm_source=gb-gplus-shareBrevet US5993463 - Remote actuation of trajectory guide
