Bone plate system and methods

• US 20050192577A1
• Filed: 10/26/2004
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Pioneer Surgical Technology Incorporated (Surgalign Holdings, Inc.)
• Original Assignee: Pioneer Laboratories Incorporated
• Inventors: Mosca, Lawrence, Janowski, Brian, Songer, Matthew N., Gephart, Matthew Peter, Korhonen, Francis, Fredin, Brad
• Granted Patent: US 7,740,649 B2
• Time in Patent Office: Days
• US Class Current: 606/86.00B
• CPC Class Codes: A61B 17/1615 Drill bits, i.e. rotating tools extending from a handpiece to contact the worked material
• CPC Class Codes: A61B 17/1655 for tapping
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1728 for holes for bone plates or plate screws
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/8009 the plate having a ratchet
• CPC Class Codes: A61B 17/8042 the additional component being a cover over the screw head
• CPC Class Codes: A61B 17/8863 Apparatus for shaping or cutting osteosynthesis equipment by medical personnel
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 17/92 Impactors or extractors, e.g. for removing intramedullary devices insertion or extraction of artificial joints A61F2/4603
• CPC Class Codes: A61B 2090/034 abutting on parts of the device itself
• CPC Class Codes: A61B 2090/061 for measuring dimensions, e.g. length

Abstract

Bone plate systems and anchor retainers are provided for use in surgical implants and bone repair. In a preferred form, the bone plate defines a multi-tier member for receiving bone anchors for securing multiple bones or bone fragments in a desired relationship. The bone plate may include bores for receiving the bone anchors, and the bores may permit and define a path of translation or shifting of the bone anchors relative to the bone plate. The anchor retainers may be held in the bores to prevent back-out of the bone anchors. The retainers may be held in a recess in an interior portion of the bore. Once the anchor member is seated within the bone plate, the retainer may rest over a top surface of the anchor member so the anchor member is impeded from backing out of the bone plate. The retainer may expand or change shape to permit an anchor member to be driven through the retainer and may contract once an anchor member has been seated within the plate so the retainer is in a configuration for preventing back-out. In addition, a tool for insertion or extraction of the bone anchors.

Claims

1. A device for stabilization of adjacent vertebrae of a spine, the device comprising:

a generally rigid plate having a bottom side generally facing a plurality of vertebrae and a top side generally facing opposite the bottom side;

a plurality of bores defined by the plate passing from the top side to the bottom side of the plate;

at least two bone anchors, each having a shank and a head with a top surface, and the anchors being insertable in one of the bores for securing the plate to the vertebrae; and

a retainer for preventing anchor back-out positioned within at least one of the bores between the top side and the bottom side of the plate, the retainer having an initial position where at least a first portion of the retainer partially intersects the bore, a passage position wherein the head of the anchor inserted therein may pass by the retainer for securing the plate to the vertebrae, and a retention position where the at least a first portion of the retainer partially intersects the bore and is located proximal to the top surface of the head;

wherein the retainer has a closed end secured with the plate and has generally straight portions extending from the closed end and across at least a portion of the bore.

2. The device of claim 1 wherein the plate has a generally arcuate shape generally consistent with lateral curvature of the vertebrae.

3. The device of claim 1 wherein the plate has a generally arcuate shape generally consistent with a curvature of the spine.

4. The device of claim 1 wherein the bores include a pair of bores for a first vertebra.

5. The device of claim 4 wherein the bores include a pair of bores for at least two vertebra.

6. The device of claim 1 wherein the device spans at least two vertebrae, and at least one bore is provided for each of the vertebrae.

7. The device of claim 6 wherein bores for a first vertebra prevent movement of the plate relative to the first vertebra, and bores for the second vertebra permit movement of the plate relative to the second vertebra.

8. The device of claim 7 wherein bores for a third vertebra permit movement of the plate relative to the third vertebra.

9. The device of claim 8 wherein the first vertebra is located intermediate the second and third vertebrae.

10. The device of claim 6 wherein at least one bore permits a anchor secured therein and to a vertebrae to translate relative to the plate within the bore.

11. The device of claim 10 wherein at least one bore prevents a anchor secured therein and to a vertebrae from translating relative to the plate within the bore.

12. The device of claim 11 wherein bores preventing anchor translation are generally circular.

13. The device of claim 11 wherein bores preventing anchor translation have retainers with a first length sized for such bores, and wherein bores permitting anchor translation have retainers with a second length sized for such bores and greater than the first length.

14. The device of claim 10 wherein bores permitting anchors to translate are elongated.

15. The device of claim 1 wherein the plate spans at least two vertebrae and defines a window located between bores for adjacent vertebrae.

16. The device of claim 15 wherein a pair of bores is provided for each vertebra, and the window is positioned so that a portion extends between the bores to provide a view of the spine at least between the vertebrae.

17. The device of claim 1 wherein each bore includes an interior surface and the interior surface defines a recess for receiving at least a portion of the retainer.

18. The device of claim 17 wherein the recesses generally define a channel.

19. The device of claim 17 wherein the first and second ends of the retainer are received in the recesses.

20. The device of claim 19 wherein the first end of the retainer includes two leg members received in a portion of the recess.

21. The device of claim 20 wherein the two legs are separated by a gap, the retainer may be compressed so as to generally close the gap.

22. The device of claim 20 wherein the plate defines a passageway extending from an edge of the plate and intersecting with the recess, and the legs being received in the passageway.

23. The device of claim 1 wherein each anchor and bore engages so the anchor is polyaxially secured in the vertebrae relative to the plate.

24. The device of claim 23 wherein the retainer for each anchor is positioned so as to be above the top surface of the anchor.

25. The device of claim 24 wherein the plate includes a shoulder extending into the bore proximate the bottom surface of the plate and defining in part the bore for receiving the shank of the anchor, the shoulder having an arcuate profile, the head of the anchor having a generally bottom surface with an arcuate profile, the shank of the anchor being smaller than the aperture, the head being larger than the portion of the bore at the shoulder, and the arcuate profile of the shoulder being complementary to the arc of the bottom surface of the head.

26. The device of claim 1 further including a tool for securing the plate to the vertebrae, wherein the tool drives the anchors into the bores and vertebrae, removes the anchors from the bores and vertebrae, and shifts the position of the retainer from the initial or retention position to the passage position.

27. The device of claim 1 wherein the head of the anchor has a generally bottom surface with an arcuate profile, and the bottom surface cams against the generally straight portions of the retainer so as to open the retainer from the initial position to the passage position so as to permit the head to pass therethrough.

28. The device of claim 27 wherein the retainer position is shifted to the retention position after the head is driven past the retainer such that the top surface of the anchor is unable to cam open the generally straight portions of the retainer so as to prevent anchor back-out.

29. The device of claim 1 wherein the retainer has a generally upwardly facing surface portion, a generally downwardly facing surface portion, and a generally inwardly facing surface portion, and the anchor head contacts at least one of the surface portions for shifting the retainer between the initial position and the retention position.

30. The device of claim 29 wherein the anchor head cams against at least one of the surface portions of the retainer for shifting the retainer.

31. The device of claim 30 wherein at least one of the surface portions of the retainer includes a cam surface for contacting the anchor head.

32. The device of claim 1 wherein the retainer forms a continuous path defining an opening within the path for permitting the anchor to pass therethrough for securing the plate to the vertebrae.

33. The device of claim 32 wherein the retainer is expandably deformable for permitting the anchor to pass therethrough for securing the plate to the vertebrae.

34. The device of claim 1 wherein the generally straight portions of the retainer extending between the first and second ends are generally parallel in the initial position.

35. The device of claim 1 wherein the generally straight portions of the retainer extending between the first and second ends are generally oblique to each other.

36. The device of claim 35 wherein the generally straight portions include a plurality of generally straight portions wherein at least two are disposed in a V-orientation.

37. The device of claim 35 wherein the generally straight portions include a plurality of obliquely positioned generally straight segments.

38. The device of claim 37 wherein the straight segments form joints, the joints are secured within a recess in the plate, and the recess is positioned intermediate the top and bottom sides of the plate and within the bore.

39. A device for stabilization of adjacent vertebrae of a spine, the device comprising:

a generally rigid plate having a bottom side generally facing a surface of a plurality of vertebrae and a top side generally facing opposite the bottom side;

a plurality of bores defined by the plate and passing from the top side to the bottom side of the plate;

bone anchors having a shank and a head with a top surface, and the anchors being insertable in the bores for securing the plate to the vertebrae; and

a retainer for preventing anchor back-out positioned at least one of the bores, the retainer having first and second end portions secured with the plate and at least one portion between the first and second end portions being deflectable from an initial position to a passage position to permit the head of a anchor to pass therethrough, and the retainer being biased to return to the initial position after the head passes therethrough thereby covering a portion of the bore.