Patent ID: 8696708
Filing Date: 2014-04-15
Classification: A61B,A61F

Abstract:
1. A facet interference screw for insertion into a facet joint between an inferior facet of a superior vertebra and a superior facet of an inferior vertebra, the facet interference screw being elongate along a central longitudinal axis, the facet interference screw comprising: a first component including a first outer semicircular surface and a first inner surface, the first outer semicircular surface intersecting with the first inner surface to define a first edge and a second edge that is spaced from the first edge in a direction direction perpendicular to the central longitudinal axis; and a second component including a second outer semicircular surface and a second inner surface, the second outer semicircular surface intersecting with the second inner surface to define a third edge and a fourth edge that is spaced from the third edge in a second direction perpendicular to the central longitudinal axis, the first and second components, when assembled with each other, define a head, a tip spaced from the head along the central longitudinal axis, and an externally threaded shaft portion extending between the head and the tip, the externally threaded shaft portion including a first thread extending uninterrupted from the first edge to the second edge along the first outer semicircular surface, the externally threaded shaft portion further including a second thread extending uninterrupted from the third edge to the fourth edge along the second outer semicircular surface, wherein when the first and second components are assembled with each other the first and second threads align to facilitate rotational implantation into the facet joint; an upper inner component having a respective outer surface configured to at least partially abut the first inner surface of the first component and a first contact surface that extends from a first location near the head to a second location near the tip; and a lower inner component having a respective outer surface configured to at least partially abut the second inner surface of the second component and a second contact surface that extends from a third location near the head to a fourth location near the tip, the second contact surface configured to engage with the first contact surface such that the upper inner component is articulable with respect to the lower inner component.