Pivotal bone anchor with collet retainer and inner locking insert
OwnerRoger P. Jackson, James L. Surberinventors
Life of this patent
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Abstract
A cervical polyaxial bone anchor includes a shank having an integral spherical head and a receiver having an upper channel for receiving a rod and a lower seat near a lower opening for receiving a closed retainer that includes a compressible upper portion engaged with the receiver seat and an expandable lower portion capturing the shank head. An outer sleeve slidable with the receiver prohibits expansion of the retainer lower portion during operation. A compression insert engages the retainer upper portion and is in friction fit with the shank head prior to fixing of an angle of the shank with respect to the receiver.
Claims14
A multi-piece receiver assembly of a bone anchor, the receiver assembly being configured to accept a rod that is locked in the receiver via a closure top, the receiver assembly comprising:
- a receiver having a longitudinal axis, a base defining an internal cavity communicating with a bottom surface of the base through a distal opening, and a pair of integral arms extending upwardly from the base to define an open channel communicating with the internal cavity;
- a retainer having an upper portion defining a retainer top surface, a lower portion defining a retainer bottom surface, and a central bore extending between the retainer top surface and the retainer bottom surface, the upper portion comprising a resilient capture structure configured to be captured within the receiver internal cavity to secure the retainer to the receiver base with the central bore aligned with the longitudinal axis;
- and
- a pressure insert configured for uploading into the receiver internal cavity through the distal opening,
- wherein after the retainer upper portion is initially captured within the receiver internal cavity, the pressure insert is upwardly deployable within the retainer central bore to engage the retainer upper portion capture structure within the receiver internal cavity and secure the retainer to the receiver base.
A multi-piece receiver assembly of a bone anchor, the receiver assembly being configured to accept a rod that is locked in the receiver via a closure top, the receiver assembly comprising:
- a receiver having a longitudinal axis, a base defining an internal cavity communicating with a bottom surface of the base through a distal opening, and a pair of integral arms extending upwardly from the base to define an open channel communicating with the internal cavity;
- a retainer having an upper portion and a lower portion with a central bore extending therethrough, the upper portion comprising a resilient capture structure comprising a plurality of resilient members separated by a plurality of vertical slots, the resilient members being configured for inward deflection during uploading through the distal opening, followed by release and capture within the receiver internal cavity to initially capture the retainer to the receiver base with the central bore aligned with the longitudinal axis;
- and
- a pressure insert pre-positioned within the retainer central bore below the retainer upper portion prior to uploading the retainer upper portion into the receiver internal cavity through the distal opening;
- wherein after the retainer upper portion is uploaded into and initially captured within the receiver internal cavity, the pressure insert is upwardly deployable within the retainer central bore to engage the retainer upper portion capture structure within the receiver internal cavity, causing the plurality of resilient members to deflect outwardly to secure the retainer to the receiver base.
Dependencies are inferred from the claim text.