ANCHORING DEVICE FOR ANCHORING A ROD IN BONES OR VERTEBRAE

• US 20090163956A1
• Filed: 12/12/2008
• Published: 06/25/2009
• Est. Priority Date: 12/13/2007
• Status: Active Grant

• Current Assignee: Biedermann Technologies GmbH & Co. KG
• Original Assignee: Biedermann Technologies GmbH & Co. KG
• Inventors: Matthis, Wilfried, Biedermann, Lutz, Pohl, Gerhard
• Granted Patent: US 8,257,399 B2
• Time in Patent Office: Days
• US Class Current: 606/265
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/7035 Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 2017/603 with three points of contact, e.g. tripod

Abstract

An anchoring device for anchoring a rod in a bone or a vertebra and for use with at least two rods having a different diameter is provided. The anchoring device includes a shaft and a head for connection to one of said rods. The head is connected to said shaft and has a recess with a base and two substantially vertically extending legs defining a channel for receiving the rod in said channel. The anchoring device further includes a fixation element for clamping said rod in said channel. The fixation element and said base each have a contact surface contacting said rod, the contact surfaces being shaped so as to be able to clamp any of the different rods.

Claims

1. An anchoring assembly for anchoring a rod to a bone or a vertebra, the anchoring assembly comprising:

at least a first rod and a second rod, a diameter of the first rod being larger than a diameter of the second rod;

a bone anchoring device comprising;

a shaft; and

a head connected to said shaft and having a recess with a base having a contact surface and two substantially vertically extending legs defining a channel for interchangeably receiving each one of said rods in said channel;

a fixation element having a contact surface facing the contact surface of the base of the head, the fixation element secured to the legs and configured to move sufficiently into and out of the recess to interchangeably clamp each of said rods in said channel;

wherein when only the first rod is received in the channel, the contact surface of the fixation element and the contact surface of the base contact the first rod to clamp the first rod in the channel; and

wherein when only the second rod is received in the channel, the contact surface of the fixation element and the contact surface of the base contact the second rod to clamp the second rod in the channel.

2. The anchoring device of claim 1, wherein said contact surfaces are shaped such that the first rod or the second rod is clamped along three contact lines.

3. The anchoring device of claim 2, wherein two of the three contact lines are located in the base and one of the contact lines is located at the fixation element.

4. The anchoring device of claim 1, wherein the fixation element has a projection on its side facing the rod, the projection being configured so as to be able to contact rods of different diameters.

5. The anchoring device of claim 1, w erein the cross section of the base is substantially V-shaped.

6. The anchoring device of claim 5, wherein side walls of the base which form the V-shape are curved.

7. The anchoring device of claim 1, wherein the contact surfaces are configured to clamp a plurality of rods with different diameters in a stepless manner.

8. The anchoring device of claim 1, wherein the head and the shaft are connected monoaxially.

9. The anchoring device of claim 1, wherein the shaft is pivotably connected to the head and wherein a pressure element is provided to lock the angular position of the shaft relative to the head and wherein the pressure element comprises the base for the rod.

10. The anchoring device of claim 1, wherein the rod has a substantially circular cross section.

11. The anchoring device of claim 1, wherein the shaft, the head and the fixation elementare made of a biocompatible material.

12. The anchoring device of claim 1, wherein the base comprises an internal hole for providing a contact surface in two areas located on both sides of the legs, respectively.

13. The anchoring device of claim 1, wherein the diameter of the first rod is larger than the diameter of the second rod by about 14%.

14. An anchoring assembly for anchoring a rod to a bone or a vertebra, the anchoring assembly comprising:

at least a first rod and a second rod, a diameter of the first rod being larger than a diameter of the second rod;

a bone anchoring device comprising a shaft and a head pivotably connected to said shaft and having two substantially vertically extending legs defining a channel for interchangeably receiving each one of said rods in said channel;

a pressure element having a recess including a base with a contact surface, the pressure element configured to lock the angular position of the shaft relative to the head;

a fixation element having a contact surface facing the contact surface of the base of the pressure element, the fixation element secured to the legs and configured to move sufficiently into and out of the channel to interchangeably clamp each of said rods in said channel;

wherein when only the first rod is received in the channel, the contact surface of the fixation element and the contact surface of the base of the pressure element contact the first rod to clamp the first rod in the channel; and

wherein when only the second rod is received in the channel, the contact surface of the fixation element and the contact surface of the base of the pressure element contact the second rod to clamp the second rod in the channel.

15. The anchoring device of claim 14, wherein the contact surface of the fixation element is defined by a projection facing the contact surface of the base of the pressure element.

16. The anchoring device of claim 14, wherein the fixation element comprises an outer fixation member configured to lock the angular position of the shaft relative to the head, and an inner fixation member comprising the contact surface facing the contact surface of the base of the pressure element and configured to move sufficiently into and out of the outer fixation member to clamp the first rod or the second rod in the channel.

17. The anchoring device of claim 16, wherein the contact surface of the inner fixation member is defined by a projection facing the contact surface of the base of the pressure element.

18. The anchoring device of claim 14, wherein the diameter of the first rod is larger than the diameter of the second rod by about 14%.

19. A method of attaching a bone anchoring assembly to a bone or a vertebra, the anchoring assembly comprising at least a first rod and a second rod, a diameter of the first rod being larger than a diameter of the second rod, a bone anchoring device comprising a shaft and a head connected to said shaft and having a recess with a base having a contact surface and two substantially vertically extending legs defining a channel for interchangeably receiving each one of said rods in said channel, a fixation element having a contact surface facing the contact surface of the base of the head, the fixation element secured to the legs and configured to move sufficiently into and out of the recess to interchangeably clamp each of said rods in said channel, wherein when only the first rod is received in the channel, the contact surface of the fixation element and the contact surface of the base contact the first rod to clamp the first rod in the channel, and wherein when only the second rod is received in the channel, the contact surface of the fixation element and the contact surface of the base contact the second rod to clamp the second rod in the channel, the method comprising:

attaching the bone anchoring device to a bone or vertebra;

inserting the first rod or the second rod in the channel; and

clamping the first rod or the second rod in the channel with the fixation element.

20. The method of claim 19, wherein the diameter of the first rod is larger than the diameter of the second rod by about 14%.