Facet joint fixation device
A facet joint fixation device formed from a flexible wedge shaped implant constructed from a single piece of material. The device is defined by an insert end spaced apart from outer end by first and second side members. Each side support is cut by a series of recesses in diminishing depth defining a living hinge therebetween. The series of recesses are constructed and arranged to adjust flexibility of said implant.
1 . A wedge-shaped implant comprising an insert end spaced apart from an outer end including an opening by a first side member and a second side member forming a living hinge structure defined by a retained material thickness, said first and second side members each formed from a continuous piece of material having a first side surface with a first series of recesses extending therefrom and perpendicular thereto, said first series of recesses along the insert end having a first depth, with diminishing depths extending toward said outer end; and
a second series of recesses extending from a second side surface positioned adjacent to and opposing said first series of recesses, with said second series of recesses having a first depth at the insert end diminishing in depth extending towards said outer end;
wherein a thickness of each said side member, measured between said first and second side surfaces, remains uniform along a length of said living hinge structure;
wherein said first and second series of recesses cooperate across said retained material thickness to define said living hinge structure configured to elastically flex along said length of said living hinge structure;
whereby said insert end can be offset from said outer end by flexure of said living hinge structure, and wherein an effective hinge profile defined by said recesses gradually reduces along said length of said living hinge structure from said outer end to said insert end.
2 . The wedge-shaped implant of claim 1 , wherein said insert end includes a tapered tip.
3 . The wedge-shaped implant of claim 1 , wherein said opening formed in the outer end comprises a threaded receptacle configured for releasable engagement during insertion of the wedge-shaped implant.
4 . The wedge-shaped implant of claim 1 wherein the insert end and the outer end are rigid.
5 . The wedge-shaped implant of claim 1 wherein said first series of recesses and said second series of recesses are constructed and arranged to adjust flexibility of said implant.
6 . The wedge-shaped implant of claim 1 wherein said wedge-shaped implant includes a tapered end extending upwards from said outer end having an outer face including a first countersunk aperture for receipt of a first pedicle screw and a second countersunk aperture for receipt a second pedicle screw.
7 . The wedge-shaped implant of claim 6 wherein said outer face is integrated with said outer end.
8 . The wedge-shaped implant of claim 6 wherein said outer face is flush with said outer end, said outer end in combination with said outer face is a curved surface or a planar surface having flat or curved sides or combinations thereof.
9 . The wedge-shaped implant of claim 6 wherein a locking member is rotatably secured to said tapered end, said locking member positioned between the first and second countersunk apertures.
10 . The wedge-shaped implant of claim 9 wherein said locking member includes a base having a raised section elevating said locking member into an installation position wherein rotation of said locking member from said installation position to a locking position biases said locking member in said locking position wherein a plurality of tabs extending from said locking member are constructed and arranged to rotate from an installation position allowing insertion of bone screws to a locking position to prohibit pedicle screw movement.