Bone fasteners and method for stabilizing vertebral bone facets using the bone fasteners

1. A fastener for stabilizing multiple bone fragments, comprising:

a first portion having a threaded outer surface configured to extend through and engage the multiple bone fragments;

a second portion connected to the first portion defining a longitudinal axis therebetween;

and

an anchor pivotally mounted between two spaced apart arms of the second portion, the anchor having a convex upper surface and a planar lower surface configured for engagement with a surface of at least one of the multiple bone fragments,

wherein the anchor is disposable between a first insertion position such that the planar surface of the anchor is substantially parallel with the longitudinal axis and a second anchoring position such that the planar surface of the anchor is transverse to the longitudinal axis so as to secure the bone segments,

wherein the first and second portions are displaceable relative to one another to reach a locked position after rotation of the anchor to the second anchoring position.

2. The fastener of claim 1 , wherein the first portion has an inner surface defining a cavity, and the second portion extends between a first end pivotally connected with the anchor and a second end having an outer surface disposable in the cavity of the first portion so as to allow displacement of the second portion relative to the first portion to establish a locked position of the fastener, the inner surface of the first portion and the outer surface of the second portion being textured to provide frictional engagement between the first and second portions of the fastener.

3. The fastener of claim 2 , wherein the textured inner surface of the first portion includes a plurality of annular ribs or threads.

4. The fastener of claim 1 , wherein the first and second portions are monolithically formed.

5. A method for operating a bone fastener used for stabilizing bone fragments, comprising the steps of:

displacing a first portion of the bone fastener through one of the bone fragments in a first direction;

displacing a second portion of the bone fastener through the bone fragments in the first direction so as to engage the first and second portions of the fastener;

displacing the fastener through the bone fragments in a second direction, opposite the first direction to orient an anchor of fastener in an anchoring position; and

displacing the first and second engaged portions relative to one another to a locked position, wherein the bone fragments are secured by the locked in fastener,

wherein the anchor is pivotally mounted between two spaced apart arms of the second portion, wherein the first and second portions are displaceable relative to one another to reach the locked position after rotation of the anchor to the second anchoring position.