Vertebral implant for promoting arthrodesis of the spine

Abstract

A vertebral implant for impaction in a disc space to restore and/or maintain desired disc space height and spinal orientation is provided. The implant has an elongated basis body having a generally lens-shape provided by convex upper and lower surfaces. Bearing surfaces are provided on the cross-edge surfaces of the endwalls. Grooves are provided in the upper and lower surfaces positioned between the bearing surfaces. The implant can be prepared from a wide variety of materials including metallic materials, synthetic materials, polymeric materials, ceramic materials, and composite materials including reinforced materials i.e. glass, fiber, and/or carbon fiber reinforced materials (CFRP).

1 - 46 . (canceled)  
   
   
       47 . An implant holder for securing an implant for impaction into a prepared disc space, said holder comprising: 
 an elongate shaft defining a longitudinal axis and having a first end to engage a handle, an opposite second end having an implant securing head;    a head extending from said second end and including a concave surface defining an implant gripping portion having a centering pin extending longitudinally from said concave surface.    
   
   
       48 . The implant holder of  claim 47  wherein the concave surface includes a pair of blades extending radially inwardly.  
   
   
       49 . The implant holder of  claim 47  wherein the concave surface comprises a shaft extendable in a direction parallel to the longitudinal axis.  
   
   
       50 . The implant of holder of  claim 47  wherein the shaft includes external threads.  
   
   
       51 . A method of treating a patient having a spinal deformity said method comprising: 
 preparing a disc space between adjacent vertebrae to receive a spinal fusion implant;    impacting a spinal fusion implant to said disc space, said spinal fusion implant comprising elongated basis body defining a longitudinal axis and which is provided with a cavity extending transverse to the longitudinal axis for receiving bone material, which cavity is bordered by two longitudinal walls located opposite one another and by two frontal walls located opposite one another, whose crosswise-extending edge surfaces serve as contact surfaces between the vertebrae and the vertebral implant, wherein the two frontal walls of the cavity are formed thicker than both of the longitudinal walls, thereby widening their crosswise-extending edge surfaces, and wherein the implant is made of synthetic material.    
   
   
       52 . A method of treating a spinal defect, said method comprising: 
 preparing a disc space between a pair of adjacent vertebrae;    cutting a portion of cortical bone from an endplate of a selected vertebra to expose cancelleous bone tissue while maintaining the apophyseal ring intact;    implanting an implant into the disc space, said implant having load bearing endwalls and upper and lower surfaces provided to engage cortical bone tissue adjacent to the exposed cancelleous bone tissue, wherein at least one of the load bearing endwalls bear against the apophyseal ring of the vertebra.    
   
   
       53 . The method of  claim 52  wherein said implant includes an interior cavity, and said upper and lower surfaces each define an opening to said interior cavity.  
   
   
       54 . The method of  claim 53  wherein said cutting provides a concave depression having a first cross sectional area measured proximal to said endplate and said upper surface defines an opening having a second cross sectional area substantially equal to said first cross sectional area.  
   
   
       55 . The method of  claim 52  wherein the upper and lower surfaces define arcuate surfaces.  
   
   
       56 . The method of  claim 52  wherein the upper and lower surfaces each include tissue-receiving grooves.  
   
   
       57 . The method of  claim 52  comprising compressing the adjacent vertebrae to embed said upper and lower surfaces into cortical bone tissue.  
   
   
       58 . The method of  claim 52  wherein said cutting includes cutting the endplates with an instrument having curved cutting edges.  
   
   
       59 . The method of  claim 52  wherein the implant is sized so both load bearing walls bear against the apophyseal ring of the vertebra.  
   
   
       60 . The method of  claim 52  wherein said cutting includes cutting a portion of each of the opposing endplates of the adjacent vertebrae.  
   
   
       61 . A vertebral implant for installation in a disc space, comprising: 
 an elongated basis body defining a longitudinal axis, which is provided with a cavity elongated along said longitudinal axis, said cavity extending transverse to the longitudinal axis and through opposite upper and lower bearing surfaces, which cavity is bordered by two planar sidewalls located opposite one another and extending along said longitudinal axis and between said upper and lower bearing surfaces, said cavity further bordered by a first endwall and a second endwall located opposite one another and extending transversely to said longitudinal axis between said sidewalls, said first endwall including rounded corners extending from a leading end toward respective ones of said sidewalls and from said leading end to said upper and lower bearing surfaces, wherein said upper bearing surface and said lower bearing surface each include a plurality of grooves formed therein extending transversely to said longitudinal axis, said plurality of grooves being located across said first and second endwalls and said planar sidewalls and are interrupted by said cavity between said planar sidewalls.    
   
   
       62 . The implant of  claim 61 , wherein said first and second endwalls are formed thicker than both of the sidewalls.  
   
   
       63 . The implant of  claim 61 , wherein adjacent ones of said grooves are separated by a land surface that is co-planar with a respective one of said upper and lower bearing surfaces.  
   
   
       64 . The implant of  claim 63 , wherein said upper bearing surface and said lower bearing surface are each convexly curved along said longitudinal axis.  
   
   
       65 . The implant of  claim 64 , wherein said sidewalls are parallel to one another.  
   
   
       66 . The implant of  claim 61 , wherein each of said grooves defines a uniform curvature cut into the respective upper and lower bearing surfaces.  
   
   
       67 . The implant of  claim 66 , wherein each of said grooves is wider along said longitudinal axis than its depth below said respective bearing surface.  
   
   
       68 . An intervertebral implant provided for impaction into a disc space between adjacent vertebrae, said implant defining a longitudinal axis and comprising: 
 an elongated body extending along said longitudinal axis;    an elongated cavity bounded by a first endwall at a leading end of said body and an opposite second endwall at a trailing end of said body, said first endwall defining a first bearing surface and an opposite second bearing surface and said second endwall defining a third bearing surface and an opposite fourth bearing surface;    an upper surface extending between said first endwall and said second endwall and having an arcuate portion adapted to engage an inferior endplate of a first vertebra; and an opposite lower surface extending between said first endwall and said second endwall and having an arcuate portion adapted to engage a superior endplate of second vertebrae, wherein said upper and lower surfaces are formed along edges of planar sidewalls on opposite sides of said cavity extending along said longitudinal axis between said first and second endwalls, and further wherein said upper surface and said lower surface each include a plurality of grooves formed therein extending transversely to said longitudinal axis, adjacent ones of said grooves being separated by a land surface that is co-planar with a respective one of said upper and lower surfaces.    
   
   
       69 . The implant of  claim 68  formed of a metallic material.  
   
   
       70 . The implant of  claim 68  formed of a non-biodegradable polymeric material.  
   
   
       71 . The implant of  claim 68 , wherein the first bearing surface, the second bearing surface, the third bearing surface and the fourth bearing surface each include at least a portion of one groove extending thereacross transversely to the longitudinal axis.  
   
   
       72 . The implant of  claim 68 , wherein said sidewalls are parallel to one another.  
   
   
       73 . The implant of  claim 68 , wherein said first endwall includes opposing rounded corners extending from said leading end toward a respective one of said sidewalls.  
   
   
       74 . The implant of  claim 68 , wherein said first and second bearing surfaces are convexly curved from said cavity to said leading end.