Bone anchoring device
DCFirst 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, the rod receiving portion having an inner wall defining a bore, the bore having a bore axis; and
a pressure member movable in the bore and comprising a first section defining a first surface for engaging the head, and a one-piece second section that is axially connected to the first section and that defines both a second surface for engaging the 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 a second position different from the first position where the head is locked relative to the receiving part; and
wherein when the pressure member is at the first position, a portion of the inner wall of the receiving part that is directed towards 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, 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.
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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.
20 Citations
41 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, the rod receiving portion having an inner wall defining a bore, the bore having a bore axis; and a pressure member movable in the bore and comprising a first section defining a first surface for engaging the head, and a one-piece second section that is axially connected to the first section and that defines both a second surface for engaging the 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 a second position different from the first position where the head is locked relative to the receiving part; and wherein when the pressure member is at the first position, a portion of the inner wall of the receiving part that is directed towards 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, 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of manufacturing 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, the rod receiving portion having an inner wall defining a bore, the bore having a bore axis, and a pressure member comprising a first section defining a first surface for engaging the head, and a one-piece second section that is axially connected to the first section and that defines both a second surface for engaging the 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 a second position different from the first position where the head is locked relative to the receiving part, the method comprising:
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inserting the head of the bone anchoring element in the receiving part; inserting the pressure member in the receiving part; and moving the pressure member to the first position to generate the preload on the head of the bone anchoring element, wherein when the pressure member is at the first position, a portion of the inner wall of the receiving part that is directed towards 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, 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. - View Dependent Claims (25, 26, 27, 28)
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29. A method for coupling a rod to a bone via 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, the rod receiving portion having an inner wall defining a bore, the bore having a bore axis, a pressure member movable in the bore and comprising a first section defining a first surface for engaging the head, and a one-piece second section that is axially connected to the first section and that defines both a second surface for engaging the rod and an outer surface, and a fixation element, the method comprising:
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inserting the bone anchoring element into a bone when the head and the pressure member are in the receiving part and the pressure member is held at a first position where friction between the first surface and the head generates a preload onto the head to maintain the shaft at a temporary angular position relative to the receiving part; applying a force greater than the friction on the bone anchoring element or the receiving part to adjust the angular position of the shaft relative to the receiving part while the pressure member is held at the first position, such that when the pressure member is at the first position, a portion of the inner wall of the receiving part that is directed towards 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, 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; inserting a rod into the rod receiving portion of the receiving part; and advancing the fixation element in the receiving part to advance the rod towards the head receiving portion, and to advance the pressure member out of the first position to a second position to lock the head relative to the receiving part and to lock a position of the rod relative to the receiving part. - View Dependent Claims (30, 31, 32)
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33. 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, the rod receiving portion having an inner wall defining a bore, the bore having a bore axis; and a pressure member movable in the bore and comprising a first section defining a first surface for engaging the head, and a one-piece second section that is axially connected to the first section and that defines both a second surface for engaging the 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 a second position different from the first position where the head is locked relative to the receiving part; wherein when the pressure member is at the first position, the inner wall of the receiving part 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, wherein at least part of the holding force acting on the outer surface of the pressure member is directed radially relative to the bore axis, 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; and wherein the second surface of the pressure member forms two legs, and wherein the pressure member can assume a third position that is located above the first position towards the first end of the receiving part, and wherein the legs of the pressure member each has a same cross-sectional profile in the first and third positions. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41)
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Specification