Bone plate with captive clips

• US 9,408,646 B2
• Filed: 02/11/2011
• Issued: 08/09/2016
• Est. Priority Date: 09/03/2003
• Status: Active Grant

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Inventors: Rathbun, David S, Suh, Sean S
• Primary Examiner(s): Isabella, David
• Assistant Examiner(s): NELSON, CHRISTINE L
• Application Number:
  US13/026,110
• Publication Number:
  US 20110137344A1
• Time in Patent Office: 2,006 Days
• Field of Search: 606/290
• US Class Current: 1/1
• 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 17/8004 with means for distracting or compressing the bone or bones
• CPC Class Codes: A61B 17/8009 the plate having a ratchet
• CPC Class Codes: A61B 17/8047 wherein the additional element surrounds the screw head in the plate hole A61B17/8052 takes precedence
• CPC Class Codes: A61B 17/8085 with pliable or malleable elements or having a mesh-like structure, e.g. small strips A61B17/8071, A61B17/8076 take precedence
• CPC Class Codes: A61B 17/8605 Heads, i.e. proximal ends projecting from bone

Abstract

A fixation system includes a plate comprising a top surface, a bottom surface, a central longitudinal axis, at least one fixation hole extending between the top and bottom surfaces and comprising an undercut therein, and at least one passage intersecting one of the undercuts. At least one resilient clip is disposed in at least a portion of the undercut, with the at least one clip having a pair of generally parallel sides and an end tab. At least one fastener is provided and comprises a head and a threaded shaft, with the head comprising a perimetral groove extending around at least a portion thereof and an instrument receiving portion. The at least one clip is configured and dimensioned to seat in the undercut with the end tab extending within the passage, and the at least one fastener is configured and dimensioned to be received in the at least one fixation hole and securable therein when the at least one clip abuts the perimetral groove of the head.

Claims

1. A bone plating system for stabilizing bones or bone fragments, including segments of the spinal column, comprising:

a bone plate having an upper plate surface, a lower plate surface, at least two pairs of fixation holes, each of the fixation holes extending between the upper plate surface and the lower plate surface and having a lower hole portion and a tapered surface;

at least one resilient clip disposed within the lower hole portion of a corresponding at least one of the fixation holes;

at least one variable angle screw comprising a first head portion and a first shaft portion that extends from the first head portion along a first central axis, the first head portion comprising a first annular ledge and a first convex surface extending from the first annular ledge to the first shaft portion, the first convex surface defining a first height from the first annular ledge to the first shaft portion along a straight line in a direction parallel to the first central axis, wherein the at least one resilient clip is disposed above the first annular ledge when the at least one variable angle screw is seated in the at least one of the fixation holes to resist the at least one variable angle screw from backing out of the bone plate, the first convex surface configured to be operatively associated with the tapered surface of the at least one of the fixation holes when the at least one variable angle screw is seated in said at least one of the fixation holes to permit the at least one variable angle screw to be inserted at a variety of insertion angles relative to the bone plate; and

at least one fixed angle screw comprising a second head portion and a second shaft portion that extends from the second head portion along a second central axis, the second head portion comprising a second annular ledge and a second convex surface disposed between the second annular ledge and the second shaft portion, the second convex surface defining a second height from the second annular ledge to the second shaft portion along a straight line that is in a direction parallel to the second central axis, the second height being less than the first height, wherein the at least one resilient clip is disposed above the second annular ledge when the at least one fixed angle screw is seated in the at least one of the fixation holes to resist the at least one fixed angle screw from backing out of the bone plate, and the second convex surface is configured to be operatively associated with the tapered surface of the at least one of the fixation holes when the at least one fixed angle screw is seated in the at least one of the fixation holes so that the at least one fixed angle screw is insertable at a pre-determined fixed angle relative to the bone plate,

wherein the first height enables the at least one variable angle screw to be inserted at the variety of insertion angles and the second height enables the at least one fixed angle screw to be inserted at the pre-determined fixed angle.

2. The system of claim 1, wherein the at least one of the fixation holes comprises at least one groove for receiving the at least one resilient clip.

3. The system of claim 2, wherein the at least one resilient clip is at least partially seated in the at least one groove to prevent the at least one resilient clip from sliding within the at least one of the fixation holes.

4. The system of claim 1, wherein the at least one variable angle screw further comprises an instrument receiving portion which communicates with the first head portion in at least one location.

5. The system of claim 1, wherein the at least one resilient clip is configured to be resiliently expandable during insertion of the at least one variable angle screw into the at least one of the fixation holes.

6. The system of claim 5, wherein the at least one resilient clip is configured to be resiliently expandable during insertion of the at least one fixed angle screw into the at least one of the fixation holes.

7. The system of claim 1, wherein the at least one resilient clip is configured to resiliently contract about the portion above the second annular ledge and resist back out when the second annular ledge of the at least one fixed angle screw is brought into contact with the at least one resilient clip.

8. The system of claim 1, wherein the at least one variable angle screw, the at least one resilient clip and its respective at least one of the fixation holes are configured to permit a trajectory of the at least one variable angle screw to change relative to the bone plate after insertion of the at least one variable angle screw into the bone.

9. The system of claim 8, wherein a range of the trajectory of the at least one variable angle screw is permitted to vary by 15 degrees.

10. The system of claim 1, wherein the edges of the at least one of the fixation holes at the upper plate surface form a horizontal plane and the at least one fixed angle screw is inserted into the at least one of the fixation holes at an angle that is offset between about 10 degrees and about 25 degrees relative to an axis perpendicular to the horizontal plane.

11. The system of claim 1, wherein the first head further includes a first trailing ledge and a groove formed between the first trailing ledge and the first annular ledge for receiving the at least one resilient clip.

12. The system of claim 11, wherein the groove extends around a perimeter of the first head portion.

13. The system of claim 1, wherein the second head further includes a second trailing ledge and a groove for receiving the at least one resilient clip that is formed between the second trailing ledge and the second annular ledge of the first head.

14. The system of claim 1, wherein the at least one variable angle screw and the at least one fixed angle screw are bone screws.

15. A bone plating system for stabilizing bones or bone fragments, including segments of the spinal column, comprising:

a bone plate having an upper plate surface, a lower plate surface, at least two pairs of fixation holes, each of the fixation holes extending between the upper plate surface and the lower plate surface and having a lower hole portion and a tapered surface;

at least one resilient clip comprising a notch portion and at least two flange portions, each of the at least two flange portions having an end portion, a recessed portion and a thickened portion, wherein the at least one resilient clip is disposed within the lower hole portion of at least one of the fixation holes;

at least one variable angle screw comprising a first head portion at a proximal end and a first shaft portion that extends distally from the first head portion along a first central axis, the first head portion comprising a first trailing ledge at the proximal end which defines a first diameter in a direction perpendicular to the first central axis, a first annular ledge disposed distally from the first trailing ledge, the first annular ledge defining a second diameter in a direction perpendicular to the first central axis, the second diameter being greater than the first diameter, a first annular groove disposed between the first trailing ledge and the first annular ledge, the first annular groove defining a first groove diameter in a direction perpendicular to the first central axis, the first groove diameter being less than the first diameter, and a first convex surface of the at least one variable angle screw extending from the first annular ledge to the first shaft portion, wherein the at least one resilient clip is disposed within the first annular groove when the at least one variable angle screw is seated in the at least one of the fixation holes to resist the at least one variable angle screw from backing out of the bone plate, the first convex surface configured to be operatively associated with the tapered surface of the at least one of the fixation holes when the at least one variable angle screw is seated in said at least one of the fixation holes to permit the at least one variable angle screw to be inserted at a variety of insertion angles relative to the bone plate; and

at least one fixed angle screw comprising a second head portion at a proximal end and a second shaft portion that extends distally from the second head portion along a second central axis, the second head portion comprising a second trailing ledge at the proximal end which defines a third diameter in a direction perpendicular to the second central axis, a second annular ledge disposed distally from the second trailing ledge, the second annular ledge defining a fourth diameter in a direction perpendicular to the second central axis, the fourth diameter being greater than the third diameter, a second annular groove disposed between the second trailing ledge and the second annular ledge, the second annular groove defining a second groove diameter in a direction perpendicular to the second central axis, the second groove diameter being less than the third diameter, and a second convex surface of the at least one fixed angle screw disposed between the second annular ledge and the second shaft portion, wherein the at least one resilient clip is disposed within the second annular groove when the at least one fixed angle screw is seated in the at least one of the fixation holes to resist the at least one fixed angle screw from backing out of the bone plate, and the second convex surface is configured to be operatively associated with the tapered surface of the at least one of the fixation holes when the at least one fixed angle screw is seated in the at least one of the fixation holes so that the at least one fixed angle screw is insertable at a pre-determined fixed angle relative to the bone plate.

16. A kit for use with bone stabilization procedures comprising:

a bone plate having an upper surface and a lower surface, a first pair of fixation holes passing through the upper surface and the lower surface and configured to be located adjacent the first vertebrae, a second pair of fixation holes passing through the upper surface and the lower surface and configured to be located adjacent the second vertebrae, wherein each fixation hole of the first pair and the second pair of fixation holes has a lower hole portion and a tapered section, and at least one resilient clip is disposed within the lower portion of at least one fixation hole of the first pair and the second pair of the fixation holes;

a plurality of variable angle screws, wherein each of the variable angle screws comprises a first head portion and a first shaft portion that extends from the first head portion along a first central axis, the first head portion comprising a first annular ledge and a first convex surface extending from the first annular ledge to the first shaft portion, the first convex surface defining a first height from the first annular ledge to the first shaft portion along a straight line in a direction parallel to the first central axis, wherein the at least one resilient clip is disposed above the first annular ledge when a variable angle screw of the plurality of variable angle screws is seated in the at least one fixation hole to resist the variable angle screw from backing out of the bone plate, the first convex surface configured to be operatively associated with the tapered surface of the at least one fixation hole when the variable angle screw is seated in said at least one fixation hole to permit the variable angle screw to be inserted at a variety of insertion angles relative to the bone plate; and

a plurality of fixed angle screws, wherein each of the fixed angle screws comprises a second head portion and a second shaft portion that extends from the second head portion along a second central axis, the second head portion comprising a second annular ledge and a second convex surface disposed between the second annular ledge and the second shaft portion, the second convex surface defining a second height from the second annular ledge to the second shaft portion along a straight line that is in a direction parallel to the second central axis, the second height being less than the first height, wherein the at least one resilient clip is disposed above the second annular ledge when a fixed angle screw of the plurality of fixed angle screws is seated in the at least one fixation hole to resist the fixed angle screw from backing out of the bone plate, and the second convex surface is configured to be operatively associated with the tapered surface of the at least one fixation hole when the fixed angle screw is seated in the at least one fixation hole so that the fixed angle screw is insertable at a predetermined fixed angle relative to the bone plate,

wherein the first height enables each of the variable angle screws to be inserted at a variety of insertion angles and the second height enables each of the fixed angle screws to be inserted at a pre-determined fixed angle.

17. The kit of claim 16, wherein the at least one resilient clip comprises a notch portion and at least two flange portions, each flange portion having an end portion, a recessed portion and a thickened portion, wherein the at least one resilient clip is disposed within the lower hole portion of the at least one fixation hole.

18. The kit of claim 16, wherein at least one of the first and second head portions comprise a groove for receiving the at least one resilient clip.