Polyaxial bone screw with cam connection and lock and release insert
First Claim
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1. A bone anchor assembly comprising:
- a) a receiver having a lower portion with a cavity and a lower opening communicating with the cavity and an upper portion with an upper opening communicating with a longitudinal connecting member receiving channel, the channel communicating with the cavity, a first receiver surface partially defines the channel and a second receiver surface partially defines the cavity;
b) a bone screw shank having a head and a body for fixation to bone, the head having an engagement surface;
c) a retaining member for capturing the shank head within the receiver, the retaining member having an interior surface sized and shaped for a locking press-fit, fixed engagement with the shank head engagement surface; and
d) a compression insert positioned in the receiver, the compression insert having at least one integral resilient structure with a portion thereof partially spaced from the insert, the resilient structure being compressible toward the insert by the receiver first surface with the insert also pressing against the shank head during non-floppy articulation of the shank head with respect to the receiver.
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Abstract
A polyaxial bone screw assembly includes, a threaded shank body having an integral upper portion receivable in a receiver, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. A retaining member for capturing the shank in the receiver includes a sloping surface for a frictional, press fit, cammed engagement with the shank. A compression insert having a resilient structure provides non-floppy positioning of the shank with respect to the receiver and also independent locking of the shank with respect to the receiver.
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Citations
28 Claims
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1. A bone anchor assembly comprising:
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a) a receiver having a lower portion with a cavity and a lower opening communicating with the cavity and an upper portion with an upper opening communicating with a longitudinal connecting member receiving channel, the channel communicating with the cavity, a first receiver surface partially defines the channel and a second receiver surface partially defines the cavity; b) a bone screw shank having a head and a body for fixation to bone, the head having an engagement surface; c) a retaining member for capturing the shank head within the receiver, the retaining member having an interior surface sized and shaped for a locking press-fit, fixed engagement with the shank head engagement surface; and d) a compression insert positioned in the receiver, the compression insert having at least one integral resilient structure with a portion thereof partially spaced from the insert, the resilient structure being compressible toward the insert by the receiver first surface with the insert also pressing against the shank head during non-floppy articulation of the shank head with respect to the receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A bone anchor comprising:
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a) a receiver having a lower portion with an inner seating surface partially defining a cavity and a lower opening communicating with the cavity and an upper portion with an upper opening communicating with a longitudinal connecting member receiving channel, the channel communicating with the cavity; b) a shank having a head with a top surface and a first sloping surface, the shank also having a body for fixation to bone; c) a retainer for capturing the shank head within the receiver cavity, the retainer having at least a second sloping surface sized and shaped for press fit engagement with the first sloping surface; and d) a compression insert positioned in the receiver, the insert sized and shaped for first and second positions with respect to the receiver, and wherein in the first position, the insert frictionally engages the receiver upper portion and the shank head is in movable frictional engagement with the insert, and in the second position, the insert frictionally engages and locks against at least one of an intermediate surface defining the channel and the receiver lower portion, the insert also frictionally locking against the shank head. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A bone anchor comprising:
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a) a receiver having a lower portion with an inner seating surface partially defining a cavity and a lower opening communicating with the cavity and an upper portion with an upper opening communicating with a longitudinal connecting member receiving channel, the channel communicating with the cavity; b) a shank having a head with at least a first engagement structure, the shank also having a body for fixation to bone; c) a retainer for capturing the shank head within the receiver cavity, the retainer having at least a second engagement structure sized and shaped for press fit engagement with the shank first engagement structure, the shank head and the retainer cooperating in such a manner that a partial rotation between the first and second engagement structures brings the shank and the retainer into the press-fit engagement; and d) a compression insert having at least one resilient outer surface feature compressible toward the insert, the resilient structure sized and shaped for pressing against the receiver and temporarily holding the insert in frictional engagement with the shank head for non-floppy positioning of the shank with respect to the receiver. - View Dependent Claims (25, 26, 27, 28)
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Specification