Spinal fixation apparatus with enhanced axial support and methods for use

• US 20020173791A1
• Filed: 04/24/2002
• Published: 11/21/2002
• Est. Priority Date: 05/17/2001
• Status: Active Grant

• Current Assignee: Medical Device Advisory Development Group, LLC
• Original Assignee: Robert S. Howland
• Inventors: Howland, Robert S.
• Granted Patent: US 6,770,075 B2
• Time in Patent Office: Days
• US Class Current: 606/61
• CPC Class Codes: A61B 17/7038 to a different extent in different directions, e.g. within one plane only
• CPC Class Codes: A61B 17/7041 with single longitudinal rod offset laterally from single row of screws or hooks A61B17/7044 takes precedence

Abstract

A spinal fixation system includes a plurality of anchor screw assemblies, e.g. including anchor screws and clamp assemblies defining rod passages therethrough. A rod is receivable in the rod passages between the anchor screw assemblies, and a spacer is securable on the rod. During use, a first anchor screw is screwed into a first vertebra, and a second anchor screw is screwed into a second vertebra adjacent the first vertebra, and clamp assemblies are mounted to each anchor screw. A rod is secured between the anchor screw assemblies, thereby fixing a relative spacing of the first and second vertebrae. A spacer is crimped onto the exposed portion of the rod between the anchor screw assemblies, the spacer extending between the anchor screw assemblies to prevent the anchor screw assemblies, and, consequently, the first and second vertebrae, from moving towards one another.

Claims

1. A spinal fixation system, comprising:

a first anchor screw assembly comprising a first passage and a first screw, the first screw having a threaded portion configured to be screwed into a first vertebra;

a second anchor screw assembly comprising a second passage and a second screw, the second screw having a threaded portion configured to be screwed into a second vertebra adjacent the first vertebra;

an elongate member receivable in the first and second passages, the elongate member comprising an exposed portion extending between the first and second anchor screw assemblies; and

a spacer securable to the exposed portion of the elongate member, the spacer having a length substantially similar to a length of the exposed portion of the elongate member for preventing the first and second anchor screw assemblies from moving substantially towards one another.

2. The spinal fixation system of claim 1, wherein the first anchor screw assembly comprises a first clamp assembly receivable on the first screw, the first clamp assembly comprising the first passage therethrough.

3. The spinal fixation system of claim 2, wherein the first clamp assembly comprises upper and lower clamp portions defining the first passage therebetween.

4. The spinal fixation system of claim 2, wherein the elongate member is at least partially curved, and wherein the first clamp assembly comprises a tapered side edge defining an angle corresponding to an angle of curvature defined by the elongate member.

5. The spinal fixation system of claim 1, wherein the first screw comprises a head portion opposite the threaded portion comprising a shoulder, and wherein the first anchor screw assembly further comprises:

a swing bolt pivotally coupled to the second portion of the screw; and

a clamp assembly on the swing bolt comprising the first passage therethrough.

6. The spinal fixation system of claim 5, wherein the swing bolt comprises a noncircular region, and wherein the clamp assembly comprises a passage having a noncircular cross-section similar to the noncircular region for seating the clamp assembly on the swing bolt.

7. The spinal fixation system of claim 6, wherein the swing bolt comprises a threaded region opposite the first screw, and wherein a fastener is threadable onto the threaded region for securing the clamp assembly on the swing bolt.

8. The spinal fixation system of claim 5, the clamp assembly comprising first and second clamp portions, the first and second clamp portions having cooperating grooves therein together defining the first passage when the first and second clamp portions are received on the swing bolt.

9. The spinal fixation system of claim 8, wherein the shoulder is radiused, and wherein the first clamp portion comprises a recess adjacent a lower surface of the first clamp portion that intersects the first passage, the recess having a radiused shape for pivotally receiving the shoulder therein before the clamp assembly is fully secured on the swing bolt.

10. The spinal fixation system of claim 1, wherein the spacer comprises a “

C”

shaped clip receivable around the elongate member, the clip comprising opposing edges that may be compressed around the elongate member to secure the clip to the elongate member.

11. A method for stabilizing vertebrae relative to one another, the method comprising:

screwing a first anchor screw into a first vertebra;

screwing a second anchor screw into a second vertebra adjacent the first vertebra;

securing an elongate member to the first and second anchor screws, thereby fixing a relative spacing of the first and second vertebrae; and

securing a spacer to the elongate member, the spacer extending substantially between the first and the second anchor screws to prevent the first and second anchor from moving towards one another.

12. The method of claim 11, wherein the step of securing the spacer involves increasing a distance between the first and second vertebrae before securing the spacer to the elongate member.

13. The method of claim 11, wherein the step of securing the elongate member comprises:

attaching a first clamp assembly to the first anchor screw assembly;

attaching a second clamp assembly to the second anchor screw assembly; and

securing the elongate member to the first and second clamp assemblies.

14. The method of claim 11, wherein the spacer comprises a “

C”

shaped clip, and wherein the step of securing a spacer comprises crimping the spacer around at least a portion of the elongate member.

15. The method of claim 11, further comprising bending the elongate member to conform to a natural curvature of the vertebrae.

16. The method of claim 11, wherein each of the first and second anchor screws comprise a swing bolt pivotally coupled to a threaded portion, the method comprising adjusting an angle of one or more of the swing bolts on the first and second anchor screws about respective pivot axes to adjust alignment of the first and second anchor screws relative to one another.

17. The method of claim 11, further comprising:

screwing a third anchor screw into a third vertebra adjacent the first vertebra;

securing the elongate member to the third anchor screw; and

securing a spacer to the elongate member between the first and the third anchor screws to prevent the first and third anchor from moving towards one another.

20. The kit of claim 18, further comprising an apparatus for bending the one or more rods to conform to a natural curvature of a patient'"'"'s spinal column.

21. The kit of claim 18, wherein the plurality of clamp assemblies comprise a plurality of upper and lower clamp portions that may be mated together to define a passage for receiving one of the one or more rods therein, the upper and lower clamp portions comprising a plurality of lengths and passage configurations.

18. A kit for stabilizing vertebrae relative to one another, comprising:

one or more substantially rigid rods,

a plurality of “

C”

shaped spacers having a plurality of lengths, the spacers comprising opposing edges defining a pocket therebetween for receiving the one or more rods therein; and

a plurality of anchor screw assemblies, the anchor screw assemblies comprising anchor screws and a plurality of clamp assemblies for receiving the one or more rods therein.

19. The kit of claim is, further comprising a crimping tool for crimping at least a portion of the opposing edges of the spacers around the one or more rods to secure the spacers to the rods.