Bone anchoring device
First Claim
1. A polyaxial bone anchoring device comprising:
- a bone anchoring element having a head and a shaft for anchoring to a bone;
a receiving part for coupling the bone anchoring element to a rod, the receiving part having a first end and a second end, a head receiving portion at the second end with an accommodation space for accommodating the head, and a rod receiving portion at the first end defining a bore in communication with the accommodation space, the bore having a bore axis; and
a one-piece pressure member movable in the bore and comprising a first surface for engaging the head, a second surface for engaging a rod, and an outer surface;
wherein when the bone anchoring element and the pressure member are in the receiving part, the pressure member is configured to assume and be held at a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and to a second position different from the first position where the head is locked relative to the receiving part; and
wherein the receiving part comprises a separate insert that is positionable in a recess formed in a side wall of the receiving part, such that when the pressure member is at the first position, an end face of the separate insert of the receiving part that is directed towards and positioned closest to the bore axis exerts a holding force on the outer surface of the pressure member to restrict movement of the pressure member towards the first end of the receiving part while portions of the separate insert that extend from the end face away from the bore axis are spaced apart from the pressure member, andwherein the pressure member is movable out of the first position towards the first end of the receiving part by applying a sufficient axial force on the pressure member while a position of the separate insert of the receiving part relative to other portions of the receiving part remains substantially constant.
2 Assignments
0 Petitions
Accused Products
Abstract
A polyaxial bone anchoring device includes a bone anchoring element having a head and a shaft, a receiving part having a head receiving portion, a rod receiving portion, and a bore having a bore axis, and a pressure member movable in the bore and having a first surface for engaging the head, wherein the pressure member is movable to a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and wherein the pressure member is configured to engage the receiving part to generate a holding force for holding the pressure member at the first position without a positive lock, and wherein the pressure member is movable in and out of the first position by applying an axial force on the pressure member greater than the holding force.
25 Citations
30 Claims
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1. A polyaxial bone anchoring device comprising:
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a bone anchoring element having a head and a shaft for anchoring to a bone; a receiving part for coupling the bone anchoring element to a rod, the receiving part having a first end and a second end, a head receiving portion at the second end with an accommodation space for accommodating the head, and a rod receiving portion at the first end defining a bore in communication with the accommodation space, the bore having a bore axis; and a one-piece pressure member movable in the bore and comprising a first surface for engaging the head, a second surface for engaging a rod, and an outer surface; wherein when the bone anchoring element and the pressure member are in the receiving part, the pressure member is configured to assume and be held at a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and to a second position different from the first position where the head is locked relative to the receiving part; and wherein the receiving part comprises a separate insert that is positionable in a recess formed in a side wall of the receiving part, such that when the pressure member is at the first position, an end face of the separate insert of the receiving part that is directed towards and positioned closest to the bore axis exerts a holding force on the outer surface of the pressure member to restrict movement of the pressure member towards the first end of the receiving part while portions of the separate insert that extend from the end face away from the bore axis are spaced apart from the pressure member, and wherein the pressure member is movable out of the first position towards the first end of the receiving part by applying a sufficient axial force on the pressure member while a position of the separate insert of the receiving part relative to other portions of the receiving part remains substantially constant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A polyaxial bone anchoring device comprising:
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a bone anchoring element having a head and a shaft for anchoring to a bone; a receiving part for coupling the bone anchoring element to a rod, the receiving part having a first end and a second end, a head receiving portion at the second end with an accommodation space for accommodating the head, and a rod receiving portion at the first end defining a bore in communication with the accommodation space, the bore having a bore axis; and a one-piece pressure member movable in the bore and comprising a first surface for engaging the head, a second surface for engaging a rod, and an outer surface; wherein when the bone anchoring element and the pressure member are in the receiving part, the pressure member is configured to assume and be held at a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and to a second position different from the first position where the head is locked relative to the receiving part; and wherein the receiving part comprises a separate insert that is positionable in a recess formed in a side wall of the receiving part, such that when the pressure member is at the first position, a substantially flat planar end face of the separate insert of the receiving part exerts a holding force that is directed radially inwardly toward the bore axis onto the outer surface of the pressure member to generate friction between the pressure member and the receiving part for restricting movement of the pressure member towards the first end of the receiving part, and wherein the pressure member is movable out of the first position towards the first end of the receiving part by applying a sufficient axial force on the pressure member while a position of the separate insert of the receiving part relative to other portions of the receiving part remains substantially constant. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A polyaxial bone anchoring device comprising:
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a bone anchoring element having a head and a shaft for anchoring to a bone; a receiving part for coupling the bone anchoring element to a rod, the receiving part having a first end and a second end, a head receiving portion at the second end with an accommodation space for accommodating the head, and a rod receiving portion at the first end defining a bore in communication with the accommodation space, the bore having a bore axis; and a one-piece pressure member movable in the bore and comprising a first end, a second end, a first surface at the second end for engaging the head, a second surface at the first end for engaging a rod, and an outer surface; wherein when the bone anchoring element and the pressure member are in the receiving part, the pressure member is configured to assume and be held at a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and to a second position different from the first position where the head is locked relative to the receiving part; and wherein the receiving part comprises a separate insert that is positionable in a recess formed in a side wall of the receiving part, such that when the pressure member is at the first position, a portion of the separate insert of the receiving part that is directed towards the bore axis contacts and exerts a holding force on the outer surface of the pressure member to restrict movement of the pressure member towards the first end of the receiving part, while a surface portion of the pressure member that extends continuously from the first end of the pressure member to a region where the separate insert of the receiving part contacts the outer surface of the pressure member is substantially parallel to a central axis of the pressure member, and wherein the pressure member is movable out of the first position towards the first end of the receiving part by applying a sufficient axial force on the pressure member while a position of the separate insert of the receiving part relative to other portions of the receiving part remains substantially constant. - View Dependent Claims (24, 25, 26)
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27. A polyaxial bone anchoring device comprising:
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a bone anchoring element having a head and a shaft for anchoring to a bone; a receiving part for coupling the bone anchoring element to a rod, the receiving part having a first end and a second end, a head receiving portion at the second end with an accommodation space for accommodating the head, and a rod receiving portion at the first end defining a bore in communication with the accommodation space, the bore having a bore axis; and a one-piece pressure member movable in the bore and comprising a first surface for engaging the head, a second surface for engaging a rod, and an outer surface; wherein when the bone anchoring element and the pressure member are in the receiving part, the pressure member is configured to assume and be held at a first position where friction between the first surface and the head generates a preload on the head to maintain the shaft at a temporary angular position relative to the receiving part, and to a second position different from the first position where the head is locked relative to the receiving part; and wherein the receiving part comprises a separate insert that is positionable in a recess formed in a side wall of the receiving part, such that when the pressure member is at the first position, an end portion of the separate insert of the receiving part exerts a holding force that is directed radially inwardly toward the bore axis onto the outer surface of the pressure member without exerting circumferential forces on the pressure member to generate friction between the pressure member and the receiving part for restricting movement of the pressure member towards the first end of the receiving part, and wherein the pressure member is movable out of the first position towards the first end of the receiving part by applying a sufficient axial force on the pressure member while a position of the separate insert of the receiving part relative to other portions of the receiving part remains substantially constant. - View Dependent Claims (28, 29, 30)
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Specification