Fixation device and method

Abstract

An implantable orthopedic stability device is disclosed. The device can have a contracted and an expanded configuration. A method of using the device between adjacent facet surfaces for support and/or fixation of either or both of the adjacent vertebrae is also disclosed.

I claim: 
     
         1 . An implantable orthopedic device, comprising:
 a first plate, having an outward-facing surface facing away from said device and an inward-facing surface opposed to said outward-facing surface, and having a plate longitudinal direction;   a second plate opposed to the first plate; and   a mechanism located between the first and second plates, the mechanism being capable of causing relative motion of the first and second plates toward or away from each other;   wherein the first plate comprises, on the inward-facing surface of the first plate, a planar ramp surface, the planar ramp surface having a ramp direction inclined at an oblique ramp angle with respect to the plate longitudinal direction;   wherein the oblique ramp angle with respect to the plate longitudinal direction is from 15 degrees to 75 degrees;   wherein the planar ramp surface is bounded on respective sides by respective first and second grooves; and   wherein the ramp surface and the first and second grooves in combination engage and capture a geometric feature of the mechanism while permitting sliding of the geometric feature relative to the planar ramp surface along the ramp direction.   
     
     
         2 . The device of  claim 1 , wherein the first plate has a centrally located first opening therethrough and the second plate has a centrally located second opening therethrough and wherein a window region of space connecting the first opening and the second opening is not crossed by any object extending within the window region continuously from a proximal edge of the window region to a distal edge of the window region. 
     
     
         3 . The device of  claim 1 , wherein each of the grooves has a pair of parallel sides and a planar connecting surface bottom between the two parallel sides. 
     
     
         4 . The device of  claim 1 , wherein the first groove has a respective groove side not coincident with the planar ramp surface, and the second groove has a respective groove side not coincident with the planar ramp surface, and the respective groove sides are substantially coplanar with each other. 
     
     
         5 . The device of  claim 1 , wherein one of the grooves has a groove side that is parallel to the planar ramp surface, and wherein one of the grooves has a groove side that is perpendicular to the planar ramp surface. 
     
     
         6 . The device of  claim 1 , wherein the first plate comprises, on the inward-facing surface of the first plate, the planar ramp surface and an additional planar ramp surface. 
     
     
         7 . The device of  claim 1 , wherein the locking element is configured to fit into the locking reception configuration such that the locking reception configuration prevents rotation of the locking element. 
     
     
         8 . The device of  claim 1 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element configured to rotate with respect to the first plate and the second plate, and wherein the locking element is completely recessed within the locking reception configuration. 
     
     
         9 . The device of  claim 1 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element configured to rotate with respect to the first plate and the second plate, and wherein the locking element is completely received by the locking reception configuration. 
     
     
         10 . An implantable orthopedic device, comprising:
 a first plate, having an outward-facing surface facing away from the device and an inward-facing surface opposed to the outward-facing surface, and having a plate longitudinal direction;   a second plate opposed to the first plate; and   a mechanism located between the first and second plates, the mechanism being capable of causing relative motion of the first and second plates toward or away from each other;   wherein the first plate comprises, on the inward-facing surface of the first plate, a planar ramp surface, wherein the planar ramp surface is inclined at an oblique ramp angle with respect to the plate longitudinal direction and defining a ramp direction, and wherein the oblique ramp angle ramp angle is from 15 degrees to 75 degrees;   wherein the ramp surface the second plate in combination engage and capture the mechanism while permitting sliding of the mechanism relative to the planar ramp surface along the ramp direction; and   wherein the first plate has a centrally located first opening therethrough and the second plate has a centrally located second opening therethrough and wherein a window region of space connecting the first opening and the second opening is not crossed by any object extending within the window region continuously from a proximal edge of the window region to a distal edge of the window region.   
     
     
         11 . The device of  claim 10 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element, wherein at least part of the radial perimeter of the locking element is surrounded by at least part of the remainder of the device prior to a locking by the locking element, and wherein the locking element is configured to fit into the locking reception configuration such that the locking reception configuration prevents rotation of the locking element. 
     
     
         12 . The device of  claim 10 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element, wherein at least part of the radial perimeter of the locking element is surrounded by at least part of the remainder of the device prior to a locking by the locking element, and wherein the locking element is completely recessed within the locking reception configuration. 
     
     
         13 . The device of  claim 10 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element, wherein at least part of the radial perimeter of the locking element is surrounded by at least part of the remainder of the device prior to a locking by the locking element, and wherein the locking element is completely received by the locking reception configuration. 
     
     
         14 . An implantable orthopedic device, comprising:
 a first plate, having an outward-facing surface facing away from the device and an inward-facing surface opposed to the outward-facing surface, and having a plate longitudinal direction;   a second plate opposed to the first plate; and   a mechanism located between the first and second plates, the mechanism being capable of causing relative motion of the first and second plates toward or away from each other;   wherein the first plate comprises, on the inward-facing surface of the first plate, a planar ramp surface bounded by two edges that are parallel to each other and generally coplanar with the plate longitudinal direction, the planar ramp surface having a ramp direction centerline midway between the two parallel edges, the centerline inclined at an oblique ramp angle with respect to the plate longitudinal direction and defining a ramp direction, and wherein the oblique ramp angle ramp angle is from 15 degrees to 75 degrees;   wherein, proceeding from a center the centerline of the planar ramp surface, perpendicular to the ramp direction the centerline planar ramp surface, on each side, the ramp surface adjoins respective first side surfaces distinct from the planar ramp surface;   wherein the respective first side surfaces adjoin respective planar second surfaces distinct from the first side surfaces, the respective planar second surfaces being parallel to the planar ramp surface;   wherein the respective second surfaces adjoin respective third surfaces distinct from the second side surfaces;   wherein the planar ramp surface and the first side surfaces and the second surfaces and the third surfaces in combination engage and capture a geometric feature of the mechanism while permitting sliding of the geometric feature relative to the planar ramp surface along the ramp direction; and   wherein the first plate has a centrally located first opening therethrough and the second plate has a centrally located second opening therethrough and wherein a window region of space connecting the first opening and the second opening is not crossed by any object extending within the window region continuously from a proximal edge of the window region to a distal edge of the window region.   
     
     
         15 . The device of  claim 14 , wherein the respective first side surfaces are planar and parallel to each other. 
     
     
         16 . The device of  claim 14 , wherein the respective third side surfaces are planar and parallel to each other. 
     
     
         17 . The device of  claim 14 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element configured to rotate with respect to the first plate and the second plate, wherein at least part of the radial perimeter of the locking element is surrounded by at least part of the remainder of the device prior to a locking by the locking element, and wherein the locking element is configured to fit into the locking reception configuration such that the locking reception configuration prevents rotation of the locking element. 
     
     
         18 . The device of  claim 14 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element configured to rotate with respect to the first plate and the second plate, wherein at least part of the radial perimeter of the locking element is surrounded by at least part of the remainder of the device prior to a locking by the locking element, and wherein the locking element is completely recessed within the locking reception configuration. 
     
     
         19 . The device of  claim 14 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element configured to rotate with respect to the first plate and the second plate, wherein at least part of the radial perimeter of the locking element is surrounded by at least part of the remainder of the device prior to a locking by the locking element, and wherein the locking element is completely received by the locking reception configuration. 
     
     
         20 . The device of  claim 14 , wherein the mechanism has a locking reception configuration at a proximal terminal end of the mechanism, the device further comprising a locking element configured to rotate with respect to the first plate and the second plate, wherein at least part of the radial perimeter of the locking element is surrounded by at least part of the remainder of the device prior to a locking by the locking element, and wherein the outer surface of the locking element is smooth.