Internal structure stabilization system for spanning three or more structures
View Patent ↗A method and system are described for immobilizing three or more vertebrae. The system includes a first bone anchor assembly, a second bone anchor assembly including a connector having a predefined arc, and at least a third bone anchor assembly. The first and second bone anchor assembly are inserted into the pedicles of vertebrae spanning at least a third vertebra. The third bone anchor assembly is positioned into the third vertebra between the first and second bone anchor assemblies using an arc defining instrument which is used to locate the proper position for the third bone anchor assembly based on the predefined arc of the connector. Once the third bone anchor assembly is in place the connector is rotated into position and captured by the first and third bone anchor assemblies.
1. A method for stabilizing more than two bones, said method comprising:
inserting a first bone anchor in a first bone;
inserting a second bone anchor in a second bone spanning at least one other bone to be braced; and
inserting a third bone anchor in a third bone between said first and second bones, the position of the proximal end of said third bone anchor being determined in at least one of its dimensions so as to lie on an arc between the proximal ends of said inserted first and second bone anchors;
inserting a proximal end of a non-linear connector in said first bone anchor, said non-linear connector having a first curvature prior to said step of inserting said first bone anchor, and said non-linear connector having a second curvature after being inserted into said first bone anchor, wherein said first curvature and said second curvature are equivalent;
pivoting said non-linear connector about its proximal end so as to bring a distal end of said non-linear connector into said second bone anchor and an intermediate surface of said non-linear connector into said third bone anchor;
wherein said arc is defined by said first curvature.
2. The method of claim 1 wherein before said step of inserting a third bone anchor the method further comprises:
attaching temporarily an arc defining instrument between said first and second bone anchors, said arc defining instrument having an arc defined by said first curvature of said connector to be connected to said bone anchors, and said arc defining instrument having a member extending from said connector to a position outside of said patient's body.
3. The method of claim 1 wherein said connector connected to said bone anchors is delivered into said patient's body coincidentally with said first bone anchor, said connector integrally attached to said first bone anchor using a poly-axial head assembly.
4. The method of claim 3 wherein after inserting a third bone anchor, said method further comprises:
rotating said connector from an orientation essentially in-line with said bone anchor to a position where said distal end of said connector is mated with the proximal end of said second bone anchor while said intermediate surface of said connector mates with the proximal end of said third bone anchor.
5. The method of claim 1 wherein said arc defining instrument is off-set from a direct line between pedicle ends of said first and second bone anchors.
6. The method of claim 2 wherein said positioning of said arc defining instrument is controlled, at least in part, by said member being attached to an extension from said third bone anchor.