Locking cap assembly for spinal fixation instrumentation

A spinal anchor assembly for securing a spinal fixation element, comprising:

• an anchor element adapted for attachment to bone and defining a central longitudinal axis, the anchor element having an open slot for receiving the spinal fixation element, side walls on opposed sides of the open slot, and a plurality of anchor flange segments extending from the side walls in a direction generally transverse to the central longitudinal axis, the anchor flange segments each including an inferior contact surface extending in a direction with respect to the central longitudinal axis that defines a radial slant;
• and
• a closure element for closing the open slot in the anchor element and applying pressure to the spinal fixation element to capture the spinal fixation element within the open slot, the closure element including a closure body and a plurality of closure flange segments extending from the closure body in a direction that is transverse to the anchor element central longitudinal axis when the closure element is placed in the open slot, each closure flange segment including a superior contact surface extending at an angle corresponding to the radial slant when the closure element is placed in the open slot so that the closure flange segment superior surfaces engage the anchor element flange segment inferior surfaces when the closure element is placed in a closed position in the anchor element open slot;
• wherein the anchor element and closure element flanges are configured to permit the closure element to be placed into the open slot in the anchor element in an open position and to be twisted into the closed position, and the radial slant is configured so that, when the closure element is in its closed position and pressure is applied to secure the spinal fixation element within the open slot in the anchor element, the anchor element and closure element flanges are drawn together.

A spinal anchor assembly for securing a spinal fixation element, comprising:

• an anchor element adapted for attachment to bone and defining a central longitudinal axis, the anchor element having an opening for receiving the spinal fixation element, side walls on opposed sides of the opening, and a plurality of inferior surfaces defined on the side walls;
• and
• a closure element for closing the opening in the anchor element and applying pressure to the spinal fixation element to capture the spinal fixation element within the opening, the closure element including a closure body and a plurality of closure flange segments extending from the closure body in a direction that is generally transverse to the anchor element central longitudinal axis when the closure element is placed in the open slot;
• and
• a locking element provided on the cap and configured so that when the closure element is placed into the opening in the anchor element in an open position and is twisted into a closed position in which the closure element flange segments and anchor element inferior surfaces to hold the closure in the opening, the locking element deters the closure element from twisting back to the open position.

An anchor assembly for securing a fixation member to bone comprising:

• an anchor element having a bone fixation member and a head, the head having an opening configured to receive a fixation member;
• a locking cap having a plurality of flanges, the flanges configured so that the locking cap can be placed into the opening in the head when the locking cap is oriented in an open position and the fixation member is received within the opening in the head, and to engage inferior contact surfaces defined on the head to hold the locking cap within the head when the locking cap is rotated to a closed position and to thereby block the fixation member from exiting the head;
• and
• a clamping element disposed on the locking cap, the clamping element being operable to clamp the fixation member to the head to prevent movement of the fixation member with respect to the head.

An anchor assembly for securing a linkage, wherein the anchor assembly comprises:

• an anchor element configured for attachment to a bone, and having a head having an open slot for receiving the linkage;
• and
• a cap for closing the open slot;
• wherein the head and the cap are adapted to twist-lock together by a partial rotation to cover the slot so as to capture the linkage, and the cap further includes a central clamping member for tightening down to secure the linkage.