Patent ID: 8491639

Claim:
An anchor device for anchoring an elongated rod to the spine, comprising: a fastener having a bone engaging portion and a head, said head of said fastener defining a socket having a socket opening; a yoke having a channel for receiving the elongated rod therein, said yoke being coupled to said head of said fastener in a manner to allow articulating movement of said yoke relative thereto, said yoke having a central bore extending therethrough and said socket of said head of said fastener having a shaped recess formed therein, said shaped recess and said central bore being alignable to receive a tool through said bore and into said recess for causing movement of said fastener relative to a bone; an element disposed within said socket for coupling said yoke to said head of said fastener in a manner to allow articulating movement of said yoke relative to said socket; an adjustable fixation structure between said yoke and said element operable to urge said element into said socket as said yoke and said element are fixed together, said adjustable fixation structure including a threaded bore defined in one of said yoke and said element, a threaded stem adapted for threaded engagement with said bore extending from the other of said yoke and said element; and a wave spring disposed between said yoke and said element and configured to releasably retain said yoke in a discrete position relative to said fastener, said wave spring including a ring body defining a center opening sized to receive said threaded stem therethrough.