Polyaxial pedicle screw
AssigneeZimmer Spine, Inc.
InventorsAlan E. Shluzas, Hugh D Hestad
Life of this patent
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Abstract
A polyaxial bone anchor including a housing, a bone screw, and a retainer for pivotably coupling the head of the bone screw to the housing. The retainer is positioned into the bore of the housing and includes a plurality of alternating tabs and slots circumferentially arranged to define a cavity for receiving the head portion of the bone screw therein. The retainer is axially moveable in the housing from a first position in which the head portion is not passable through the lower opening of the retainer to a second position in which the head portion is passable through the lower opening of the retainer.
Claims26
A polyaxial bone anchor comprising:
- an upper housing component comprising:
- an upper end;
- a lower end;
- a bore extending through the upper housing component from the upper end to the lower end along a longitudinal axis;
- and
- a channel configured for receiving an elongate stabilization member therethrough which extends from a first side surface of the upper housing component to a second side surface of the upper housing component opposite the first side surface transverse to the bore;
- a lower housing component attached to the lower end of the upper housing component so that at least a portion of a radially outer surface of the lower housing component is exposed to an exterior of the polyaxial bone anchor, wherein the lower housing component is rotatable relative to the upper housing component about the longitudinal axis;
- a spacer positioned within the bore proximate the lower end of the upper housing component at least partially within the lower housing component such that the upper housing component, the lower housing component and the spacer are at least partially concentric;
- a ring positioned concentrically between the spacer and the upper housing component and that axially engages the upper housing component;
- and
- a bone screw including a head portion and a shank extending from the head portion, the head portion of the bone screw positionable in the bore to engage the spacer without engaging the ring and with the shank extending from the lower end of the upper housing component and the head portion engaging the spacer.
A polyaxial bone anchor comprising:
- an upper housing component comprising:
- an upper end;
- a lower end;
- a bore extending through the upper housing component from the upper end to the lower end along a longitudinal axis;
- and
- a channel configured for receiving an elongate stabilization member therethrough which extends from a first side surface of the upper housing component to a second side surface of the upper housing component opposite the first side surface transverse to the bore;
- a lower housing component separate from and coupled to the lower end of the upper housing component such that an upward-facing surface of the lower housing component faces a downward-facing feature of the upper housing component;
- a spacer positioned within the bore proximate the lower end of the upper housing component at least partially within the lower housing component, the spacer including an upward-facing surface that faces the downward-facing feature of the upper housing component;
- a ring positioned against the downward-facing feature of the upper housing component and the lower housing component and radially between the upper housing component and the spacer;
- a bone screw including a head portion and a shank extending from the head portion, the head portion of the bone screw positionable in the bore to engage the spacer and with the shank extending from the lower end of the upper housing component and the head portion engaging the spacer;
- and
- a plurality of deflectable members coupled to the head portion of the bone screw to inhibit axial displacement of the bone screw out of the bore.
Dependencies are inferred from the claim text.