Rod attachment for head to head cross connector
Exemplary spinal fixation devices, systems, and method are provided for stabilizing vertebrae in a patient's spine. In one exemplary embodiment, methods and devices are provided for coupling one or more bone anchors, such as hooks, screws, etc., and/or one or more spinal fixation elements, such as spinal rods, cables, plates, etc. In certain exemplary embodiments, a cross connector is provided for connecting and stabilizing two bone anchors, a bone anchor and a spinal fixation element, or a bone anchor and bone.
1. A spinal fixation system, comprising:
a bone anchor having a bone-engaging portion and a rod receiving portion with opposed arms configured to receive a rod therebetween;
a connecting member having first and second ends, the first end having an opening extending therethrough and having a distal surface that bears against a proximal terminal end surface of each of the opposed arms of the rod receiving portion of the bone anchor; and
a closure mechanism having a portion that extends through the opening in the first end of the connecting member and having threads formed thereon and configured to threadably engage threads formed on the opposed arms of the rod receiving portion of the bone anchor.
2. The spinal fixation system of claim 1 , wherein the closure mechanism comprises a set screw.
3. The spinal fixation system of claim 1 , further comprising a fastening element configured to mate to the closure mechanism to lock the connecting member to the rod receiving portion of the bone anchor.
4. The spinal fixation system of claim 3 , wherein the fastening element comprises a locking nut configured to threadably engage the closure mechanism.
5. The spinal fixation system of claim 3 , wherein the fastening element includes a head and a threaded shank that extends distally from the head.
6. The spinal fixation system of claim 5 , wherein a distal-facing surface of the head of the fastening element is configured to bear against a proximal surface of the first end of the connecting member, and wherein the threaded shank extends from the distal-facing surface and is configured to extend into a threaded bore formed in the closure mechanism.
7. The spinal fixation system of claim 1 , wherein, when a rod is disposed between the opposed arms of the rod receiving portion, the connecting member is oriented at an angle in a range between about 20° and about 160° relative to the rod.
8. The spinal fixation system of claim 1 , wherein, when a rod is disposed between the opposed arms of the rod receiving portion, the connecting member is oriented at an angle in a range between about 60° and about 120° relative to the rod.
9. The spinal fixation system of claim 1 , wherein the bone anchor comprises a polyaxial screw.
10. A spinal fixation system, comprising:
a bone anchor having a bone-engaging portion and a rod receiving portion with opposed arms that receive a rod therebetween;
a rod disposable between the opposed arms of the rod receiving portion of the bone anchor;
a connecting member having first and second ends, the first end having a distal surface that bears against a proximal terminal end surface of the opposed arms of the rod receiving portion of the bone anchor; and
a set screw configured to extend through an opening formed in the first end of the connecting member and having threads configured to threadably engage the opposed arms of the rod receiving portion of the bone anchor.
11. The spinal fixation system of claim 10 , further comprising a fastening nut configured to threadably mate to the set screw to lock the connecting member to the rod receiving portion of the bone anchor.
12. The spinal fixation system of claim 10 , further comprising a fastening element having a head and a threaded shank that extends distally from the head and that is configured to extend into a threaded bore formed in the set screw.
13. The spinal fixation system of claim 12 , wherein a distal-facing surface of the head of the fastening element is configured to bear against a proximal surface of the first end of the connecting member.
14. A spinal fixation system, comprising:
first and second bone anchors, each bone anchor having a bone-engaging portion and a rod receiving portion with opposed arms that receive a rod therebetween;
a fixation element disposable between the opposed arms of the rod receiving portion of the first and second bone anchors for connecting the first and second bone anchors;
a cross connector configured to span between opposed lateral sides of a vertebra and having first and second ends, the first end of the cross connector having a distal surface that bears against a proximal terminal end surface of the opposed arms of the rod receiving portion of the first bone anchor;
a closure mechanism configured to mate to the opposed arms of the rod receiving portion of the first bone anchor to lock the fixation element to the first bone anchor; and
locking element configured to engage the closure mechanism to lock the cross connector to the rod receiving portion of the first bone anchor.
15. The spinal fixation system of claim 14 , wherein a portion of the closure mechanism is configured to extend through the first end of the cross connector when the closure mechanism is mated to the opposed arms.
16. The spinal fixation system of claim 14 , wherein the closure mechanism comprises a set screw that threadably mates with threads formed on the opposed arms of the rod receiving portion of the first bone anchor.
17. The spinal fixation system of claim 14 , wherein the locking element comprises a locking nut configured to threadably mate to the closure mechanism.
18. The spinal fixation system of claim 14 , wherein the locking element includes a head and a threaded shank, the threaded shank being configured to threadably mate with a threaded bore formed in the closure mechanism.