Implant connectors and related methods
Implant connectors and related methods are disclosed herein. In some embodiments, a connector can include a low-profile portion to facilitate use of the connector in surgical applications where space is limited. In some embodiments, a connector can include a biased rod-pusher to allow the connector to “snap” onto a rod and/or to “drag” against the rod, e.g., for provisional positioning of the connector prior to locking.
1. A connector, comprising:
a body that defines first and second rod-receiving recesses, the body having proximal and distal ends that define a proximal-distal axis extending therebetween;
a rod pusher slidably disposed within a tunnel formed in the body and configured to translate with respect to the body along a rod pusher axis;
a first set screw threadably received in the body to translate the rod pusher along the rod pusher axis and lock a first rod within the first rod-receiving recess; and
a second set screw threadably received in the body to lock a second rod within the second rod-receiving recess,
wherein the first and second set screws have a common rotation axis.
2. The connector of claim 1 , further comprising a bias element configured to bias the rod pusher along the rod pusher axis towards the first rod-receiving recess.
3. The connector of claim 2 , wherein the bias element is received within a through-bore formed in the rod pusher.
4. The connector of claim 2 , wherein the bias element comprises a leaf spring received within a through-bore formed in the rod pusher and first and second recesses formed in the body.
5. The connector of claim 4 , wherein the first and second recesses are defined by first and second bore holes formed in a distal-facing surface of the body.
6. The connector of claim 4 , wherein the through-bore in the rod pusher includes a reduced-width middle portion and opposed end portions having an increased width, the middle portion being defined at least in part by a pin inserted through a pin hole that intersects the through-bore in the rod pusher.
7. The connector of claim 1 , wherein the first rod-receiving recess is open in a distal direction and wherein the second rod-receiving recess is open in a proximal direction.
8. The connector of claim 1 , wherein the rod pusher axis is substantially perpendicular to the proximal-distal axis.
9. The connector of claim 1 , wherein the first rod-receiving recess is formed in a wing portion of the body, the wing portion having a height dimension extending parallel to a longitudinal axis of the first rod-receiving recess, wherein the height of the wing portion is less than about 5 mm.
10. The connector of claim 1 , wherein the first rod-receiving recess is formed in a wing portion of the body, the wing portion having a height dimension extending parallel to a longitudinal axis of the first rod-receiving recess, wherein a ratio of the height of the wing portion to a diameter of the first rod-receiving recess is less than about 2:1.
11. The connector of claim 1 , wherein advancing the first set screw proximally relative to the body causes a surface of the first set screw to bear against a bearing surface of the rod pusher to urge the rod pusher towards the first rod-receiving recess and to lock a first rod therein.
12. The connector of claim 1 , wherein a drag force is exerted on a first rod when the first rod is disposed in the first rod-receiving recess.
13. The connector of claim 1 , wherein the connector provides tactile feedback when a first rod is snapped into the first rod-receiving recess.
14. The connector of claim 1 , wherein the common rotation axis is parallel to the proximal-distal axis.
15. The connector of claim 1 , wherein the rod pusher has a first bearing surface configured to bear against a first rod disposed in the first rod-receiving recess, a second bearing surface configured to bear against the first set screw, and a third bearing surface configured to bear against a second rod disposed in the second rod-receiving recess.
16. A connector, comprising:
a body that defines first and second rod-receiving recesses, the body having proximal and distal ends that define a proximal-distal axis extending therebetween;
a rod pusher slidably disposed within a tunnel formed in the body and configured to translate with respect to the body along a rod pusher axis;
a first set screw threadably received in the body to translate the rod pusher along the rod pusher axis and lock a first rod within the first rod-receiving recess, and
a second set screw threadably received in the body to lock a second rod within the second rod-receiving recess,
wherein rotating the first set screw in a first direction moves the first set screw proximally to lock a first rod within the first rod-receiving recess and wherein rotating the second set screw in the first direction moves the second set screw distally to lock a second rod within the second rod-receiving recess.
17. A method of connecting first and second spinal rods, comprising:
positioning a first spinal rod within a first rod-receiving recess formed in a body portion of a connector;
rotating a first set screw within the body about a rotation axis to translate a rod pusher within the body towards the first rod-receiving recess and thereby urge the rod pusher against the first spinal rod to lock the first spinal rod to the connector;
positioning a second spinal rod within a second rod-receiving recess formed in the body portion of the connector; and
rotating a second set screw within the body about the rotation axis to lock the second spinal rod to the connector.
18. The method of claim 17 , wherein locking the second spinal rod comprises tightening a second set screw within the body.
19. The method of claim 17 , further comprising hooking a wing portion of the connector onto the first rod at a location between two bone anchors to which the first rod is coupled, the two bone anchors being implanted in adjacent vertebral levels of a patient's spine.
20. The method of claim 17 , wherein positioning the first spinal rod within the first rod-receiving recess comprises displacing the rod pusher away from the first rod-receiving recess and at least one of bending, straining, deflecting, and compressing a bias element acting on the rod pusher such that the rod pusher exerts a drag force on the first rod before the first set screw is tightened.
21. The method of claim 17 , wherein tightening the first set screw comprises contacting a ramped surface of the set screw with a corresponding ramped surface of the rod pusher.
22. The method of claim 17 , wherein locking the second rod comprises forcing the second rod against the rod pusher to force the rod pusher against the first rod.
23. A method of connecting first and second spinal rods, comprising:
positioning a first spinal rod within a first rod-receiving recess formed in a body portion of a connector;
tightening a first set screw within the body to translate a rod pusher within the body towards the first rod-receiving recess and thereby urge the rod pusher against the first spinal rod to lock the first spinal rod to the connector;
positioning a second spinal rod within a second rod-receiving recess formed in the body portion of the connector; and
locking the second spinal rod to the connector by tightening a second set screw within the body,
wherein rotating the first set screw in a first direction moves the first set screw proximally to lock the first rod within the first rod-receiving recess and wherein rotating the second set screw in the first direction moves the second set screw distally to lock the second rod within the second rod-receiving recess.