Facet screw and method for spinal stabilization
First Claim
1. A facet screw, comprising:
- a cannulated elongated body extending between a proximal end and distal end and having a longitudinal axis;
the elongated body comprising;
a head portion at the proximal end having a threaded outer surface, a socket open to the proximal end and a seating flange that extends radially outwardly;
a threaded portion located distally of the head portion and having threads formed in the outer surface of the elongate body;
a threadless distal portion located distally of the threaded portion and extending along the elongate body from the threaded portion to the distal end;
at least one flute formed longitudinally in the elongate body located at the distal end and extending proximally toward the proximal end;
the flute extending proximally into the threaded portion and interrupting threads at the distal end of the threaded portion;
the flute having a radial cutting face intersecting with the outer surface of the elongate body at a straight cutting edge;
the flute having a curved heel face that interconnects with the cutting face at one end and intersects with the outer surface at a heel edge;
wherein the heel edge is curved; and
a distal tapered portion extending proximally along the elongate body from the distal end;
the distal tapered portion having a diameter that decreases in the distal direction;
wherein the distal tapered portion includes the threadless distal portion.
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Accused Products
Abstract
A spinal facet bone screw and minimally invasive surgical method of implanting a facet screw to stabilize the spine are provided. The facet screw includes an elongated body portion having a head, a threaded portion and a distal threadless portion. A pair of flutes formed in the elongated body extends from the distal end across the threadless portion and into the distal end of the threaded portion. The flute creates a self-tapping cutting surface that includes a heel edge that is curved with respect to the outer surface. The method of implantation comprises making a minimally invasive incision on the side of the midline contralateral to the target facet joint and delivering the screw across the interspinous process using the adjacent spinous processes as guideposts. The facet screw system fixes juxtaposed facet articular processes to enhance spinal fusion and stability and the method provides for accurate, repeatable and easy implantation.
79 Citations
19 Claims
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1. A facet screw, comprising:
a cannulated elongated body extending between a proximal end and distal end and having a longitudinal axis;
the elongated body comprising;a head portion at the proximal end having a threaded outer surface, a socket open to the proximal end and a seating flange that extends radially outwardly; a threaded portion located distally of the head portion and having threads formed in the outer surface of the elongate body; a threadless distal portion located distally of the threaded portion and extending along the elongate body from the threaded portion to the distal end; at least one flute formed longitudinally in the elongate body located at the distal end and extending proximally toward the proximal end;
the flute extending proximally into the threaded portion and interrupting threads at the distal end of the threaded portion;
the flute having a radial cutting face intersecting with the outer surface of the elongate body at a straight cutting edge;
the flute having a curved heel face that interconnects with the cutting face at one end and intersects with the outer surface at a heel edge;
wherein the heel edge is curved; anda distal tapered portion extending proximally along the elongate body from the distal end;
the distal tapered portion having a diameter that decreases in the distal direction;
wherein the distal tapered portion includes the threadless distal portion.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A surgical method for implanting a facet screw into a spine of a patient comprising the steps of:
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identifying a target facet joint located on a first side of a midline of a patient'"'"'s spine;
the target facet joint comprising the inferior articular face of a first vertebral body and the superior articular face of an adjacent lower second vertebral body;inserting a facet screw into a patient at a point of skin penetration located on a second side of the midline of the patient'"'"'s spine that is opposite from the first side of the midline and cephalad of the target facet joint; moving the facet screw subcutaneously from the point of skin penetration through an interspinous ligament located between the first vertebral body and adjacent higher third vertebral body at a point of interspinous ligament penetration; moving the facet screw subcutaneously from the point of interspinous ligament penetration to the first vertebral body at a location adjacent to the target facet joint on the first side of the midline; delivering the facet screw into the bone of the first vertebral body at a location adjacent to the target facet joint; and driving the facet screw across the upper and lower articular faces of the target facet joint. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A surgical method for implanting a facet screw across a target facet joint comprising a first vertebral body and a second vertebral body in a minimally invasive surgical procedure comprising the steps of:
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delivering the facet screw through a skin incision contralateral to the target facet joint; passing the facet screw through the interspinous ligament to a location on the first vertebral body adjacent to the target facet joint; and driving the facet screw into the first vertebral body; using the spinous process of the first vertebral body and the spinous process of an adjacent higher third vertebral body as guideposts; and fixing the target facet joint with the facet screw.
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Specification