Bone anchoring device
A bone anchoring device includes a bone anchoring element having a shaft to be anchored in the bone and a head, a receiving part for receiving a rod to be connected to the bone anchoring element, and a pressure member acting onto the head to lock the position of the head relative to the receiving part, the receiving part is formed in one piece and includes an open first bore with a first bore axis, a recess shaped and sized to receive a rod having a longitudinal axis, and a second bore having a second bore axis. The second bore is in communication with the first bore and is sized to receive the head with a part of the shaft extending through the second bore. The second bore axis includes an angle of approximately 90° with a plane defined by the first bore axis and the longitudinal axis of the rod.
1. A bone anchoring device comprising:
a bone anchoring element having a shaft to be anchored in a bone and a head having a spherical surface portion;
a receiving part for receiving a rod to be connected to the bone anchoring element, the rod having a longitudinal axis, the receiving part being formed in one piece and comprising:
a first bore extending from a first open end to a second end along a first bore axis;
two legs having first free ends at the first open end of the bore and extending from the first free ends in a direction of the first bore axis to second ends of the legs wherein the legs are joined to define a U-shaped recess shaped and sized to receive the rod;
a second bore having a second bore axis, the second bore being in communication with the first bore and being sized to receive the head with a part of the shaft extending through the second bore; wherein the second bore is configured to block the shaft of the bone anchoring element, when the bone anchoring element is seated within the receiving part, from moving to a position wherein a longitudinal axis of the shaft is alianed with the first bore axis;
wherein an angle between the second bore axis and a plane defined by the first bore axis and the longitudinal axis of the rod is approximately 90°; and
a pressure member acting onto the head to lock the position of the head relative to the receiving part.
2. The bone anchoring device according to claim 1 , wherein the first bore axis and the second bore axis intersect each other.
3. The bone anchoring device according to claim 1 , wherein pivoting of the bone anchoring element is allowed when the bone anchoring element is seated within the receiving part.
4. The bone anchoring device according to claim 1 , wherein the second bore comprises a section with a diameter increasing toward the outer wall of the receiving part to allow pivoting of the bone anchoring element when the bone anchoring element is seated within the receiving part.
5. The bone anchoring device according to claim 1 , wherein the receiving part comprises a third bore having a third bore axis, the third bore being in communication with the second bore and arranged on the side of the receiving part which is opposite to the second bore.
6. The bone anchoring device according to claim 5 , wherein the second bore axis and the third bore axis are substantially coaxial.
7. The bone anchoring device according to claim 5 , wherein the diameter of the third bore is larger than the largest diameter of the head.
8. The bone anchoring device according to claim 5 , wherein the diameter of the third bore is smaller than the largest diameter of the head.
9. The bone anchoring device according to claim 1 , wherein the diameter of the second bore is smaller than the largest diameter of the head.
10. The bone anchoring device according to claim 1 , wherein the diameter of the second bore is larger than the largest diameter of the head.
11. The bone anchoring device according to claim 1 , wherein the angle between the second bore axis and the plane is 90°±12°.
12. The bone anchoring device according to claim 1 , wherein the bone anchoring element is pivotable when seated within the receiving part in an angle of 10° relative to the second bore axis.
13. The bone anchoring device according to claim 1 , wherein the receiving part comprises a seat for the head, the seat being part of a surface of the second bore.
14. The bone anchoring device according to claim 1 , wherein the seat has a spherical surface portion which corresponds to the spherical surface portion of the head.
15. The bone anchoring device according to claim 1 , wherein the pressure member has the spherical surface portion which corresponds to a spherical surface of the head.
16. The bone anchoring device according to claim 1 , wherein the head comprises a projection at its end opposite to the shaft for engagement with a tool.
17. A method of using a bone anchoring device, the bone anchoring device comprising a bone anchoring element having a shaft to be anchored in a bone and a head having a spherical surface portion, a receiving part for receiving a rod to be connected to the bone anchoring element, the rod having a longitudinal axis, the receiving part being formed in one piece and comprising a first bore extending from a first open end to a second end along a first bore axis, two legs having first free ends at the first open end of the bore and extending from the first free ends in a direction of the first bore axis to second ends of the legs wherein the legs are joined to define a U-shaped recess shaped and sized to receive the rod, a second bore having a second bore axis, the second bore being in communication with the first bore and being sized to receive the head with a part of the shaft extending through the second bore, wherein the second bore is configured to block the shaft of the bone anchoring element, when the bone anchoring element is seated within the receiving part, from moving to a position wherein a longitudinal axis of the shaft is aligned with the first bore axis, wherein an angle between the second bore axis and a plane defined by the first bore axis and the longitudinal axis of the rod is approximately 90°, and a pressure member, the method comprising:
inserting the bone anchoring element in the receiving part; and
inserting the pressure member in the receiving part, the pressure member configured to act on the head to lock the position of the bone anchoring element relative to the receiving part.
18. The method according to claim 17 , wherein inserting the bone anchoring element comprises inserting the head first from outside the receiving part through the second bore.
19. The method according to claim 17 , wherein inserting the bone anchoring element comprises inserting the shaft first from outside the receiving part through a third bore of the receiving part, the shaft at least partly extending through the second bore such that the head is inserted in the receiving part from outside the receiving part through the third bore, the third bore being on an opposite side of the receiving part relative to the second bore.
20. The method according to claim 17 , further comprising screwing the shaft into a bone with a tool inserted into a third bore of the receiving part being on an opposite side of the receiving part relative to the second bore, the tool engaging a portion of the head.