Intervertebral spacer

Abstract

An intervertebral spacer adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc. The spacing member may include an external, non-porous, concavo-convex contour with respect to one dimension of the spacing member. The spacing member may be constructed from a rigid, non-resilient load-bearing material that is incapable of elastic deformation. The spacing member may be inserted with the aid of a sheathed trocar device that is releasably attached to the spacer, to enable implantation and selective positioning of the spacer by the surgeon from the posterior side of the spine, without the need to retract the dural nerve or the posterior longitudinal ligament.

1 . An intervertebral spacing implant comprising: 
 a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;    wherein the spacing member comprises a solid body;    wherein the spacing member comprises an upper surface and a lower surface and a free insertion end, and wherein at least one of said upper surface and said lower surface comprises a male corner line, and wherein said spacing member includes a tapered portion between said male corner line and said free insertion end of said spacing member such that said spacing member becomes progressively thinner from said male corner line toward said free insertion end of said spacing member, wherein said tapered portion is characterized by at least one smooth surface that is a part of either said upper surface or said lower surface and extends from said male corner line to said free insertion end, said smooth surface having an absence of corners, points or other abrupt edges; and    wherein said spacing member comprises a sidewall around a perimeter of said spacing member, said sidewall having a smooth contour characterized by an absence of corners extending from said upper surface to said lower surface.    
   
   
       2 . The intervertebral spacing implant of  claim 1 , wherein the spacing member is either inherently non-porous or is otherwise rendered non-porous.  
   
   
       3 . The intervertebral spacing implant of  claim 1 , wherein the spacing member is constructed from a rigid, non-resilient load-bearing material.  
   
   
       4 . The intervertebral spacing implant of  claim 1 , wherein the spacing member defines an imaginary arcuate centerline residing between opposing sides of the external concavo-convex contour of said spacing member, said arcuate centerline forming less than half a circle.  
   
   
       5 . The intervertebral spacing implant of  claim 1 , wherein said spacing member has a cashew shape having a uniform width along a majority length of the spacing member.  
   
   
       6 . The intervertebral spacing implant of  claim 1 , wherein the spacing member comprises a bone material.  
   
   
       7 . The intervertebral spacing implant of  claim 1 , wherein the spacing member comprises metal.  
   
   
       8 . The intervertebral spacing implant of  claim 1 , wherein the spacing member comprises titanium.  
   
   
       9 . The intervertebral spacing implant of  claim 1 , wherein the spacing member comprises ceramic.  
   
   
       10 . The intervertebral spacing implant of  claim 1 , wherein the spacing member includes an anterior wall and a posterior wall, and wherein the external concavo-convex contour of the spacer is defined by the posterior wall being concave in a horizontal dimension and by the anterior wall being convex in a horizontal dimension.  
   
   
       11 . The intervertebral spacing implant of  claim 10 , wherein the anterior wall and the posterior wall of the spacing member are each linear in a vertical dimension.  
   
   
       12 . The intervertebral spacing implant of  claim 1 , wherein the concavo-convex contour comprises a concave posterior side, and a convex anterior side disposed in a substantially parallel orientation with respect to the concave posterior side.  
   
   
       13 . The intervertebral spacing implant of  claim 1 , wherein the spacing member further comprises a disc-like member having a thickness at a thickest part of the spacing member, and a length that is greater in length than said thickness at said thickest part, and a width that is greater in width than said thickness at said thickest part.  
   
   
       14 . The intervertebral spacing implant of  claim 13 , wherein the width of the spacing member is defined by a perimeter wall that constitutes the concave side and the convex side of the external concavo-convex contour of said spacing member.  
   
   
       15 . The intervertebral spacing implant of  claim 1 , wherein the spacing member further comprises a plurality of spaced-apart recesses formed in said upper surface.  
   
   
       16 . The intervertebral spacing implant of  claim 15 , wherein the recesses are elongate and are disposed in a substantially parallel orientation with respect to each other.  
   
   
       17 . The intervertebral spacing implant of  claim 16 , wherein the recesses extend in an anterior-to-posterior direction.  
   
   
       18 . The intervertebral spacing implant of  claim 15 , wherein the spaced-apart recesses comprise opposing sidewalls disposed at a non-parallel angle with respect to each other.  
   
   
       19 . The intervertebral spacing implant of  claim 18 , wherein said angle is within a range of between approximately 45 degrees and 75 degrees.  
   
   
       20 . The intervertebral spacing implant of  claim 19 , wherein said angle is approximately 60 degrees.  
   
   
       21 . The intervertebral spacing implant of  claim 1 , wherein said spacing member further comprises attachment means for releasably attaching positioning means to said spacing member.  
   
   
       22 . The intervertebral spacing implant of  claim 21 , wherein said attachment means are positioned on an end of said spacing member opposite said free insertion end.  
   
   
       23 . The intervertebral spacing implant of  claim 21 , wherein said attachment means for releasably attaching positioning means to said spacing member comprises a recess in said spacing member.  
   
   
       24 . The intervertebral spacing implant of  claim 23 , wherein said attachment means for releasably attaching positioning means to said spacing member comprises a threaded bore.  
   
   
       25 . An intervertebral spacing implant comprising: 
 a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;    wherein the spacing member defines an imaginary arcuate centerline residing between opposing sides of the external concavo-convex contour of said spacing member;    wherein the spacing member comprises a first end, a second end, and a length between said first end and said second end;    wherein said spacing member includes a tapered portion at said second end such that said spacing member becomes progressively thinner toward said second end of said spacing member;    wherein said tapered portion extends along only a portion of said length; and    wherein said spacing member comprises a sidewall around a perimeter of said spacing member, said sidewall having a smooth contour characterized by an absence of corners extending from said upper surface to said lower surface.    
   
   
       26 . The intervertebral spacing implant of  claim 25 , wherein the spacing member is solid and is either inherently non-porous or is otherwise rendered non-porous.  
   
   
       27 . The intervertebral spacing implant of  claim 25 , wherein the spacing member is constructed from a rigid, non-resilient load-bearing material.  
   
   
       28 . The intervertebral spacing implant of  claim 25 , wherein said arcuate centerline forms less than half a circle.  
   
   
       29 . The intervertebral spacing implant of  claim 25 , wherein said spacing member has a cashew shape having a uniform width along a majority length of the spacing member.  
   
   
       30 . The intervertebral spacing implant of  claim 25 , wherein the spacing member comprises a bone material.  
   
   
       31 . The intervertebral spacing implant of  claim 25 , wherein the spacing member includes an anterior wall and a posterior wall, and wherein the external concavo-convex contour of the spacer is defined by the posterior wall being concave in a horizontal dimension and by the anterior wall being convex in a horizontal dimension.  
   
   
       32 . The intervertebral spacing implant of  claim 31 , wherein the anterior wall and the posterior wall of the spacing member are each linear in a vertical dimension.  
   
   
       33 . The intervertebral spacing implant of  claim 25 , wherein the concavo-convex contour comprises a concave posterior side, and a convex anterior side disposed in a substantially parallel orientation with respect to the concave posterior side.  
   
   
       34 . The intervertebral spacing implant of  claim 25 , wherein the spacing member further comprises a disc-like member having a thickness at a thickest part of the spacing member, and a length that is greater in length than said thickness at said thickest part, and a width that is greater in width than said thickness at said thickest part.  
   
   
       35 . The intervertebral spacing implant of  claim 34 , wherein the width of the spacing member is defined by a perimeter wall that constitutes the concave side and the convex side of the external concavo-convex contour of said spacing member.  
   
   
       36 . The intervertebral spacing implant of  claim 25 , wherein the spacing member further comprises a plurality of spaced-apart recesses formed in said upper surface.  
   
   
       37 . The intervertebral spacing implant of  claim 36 , wherein the recesses are elongate and are disposed in a substantially parallel orientation with respect to each other.  
   
   
       38 . The intervertebral spacing implant of  claim 37 , wherein the recesses extend in an anterior-to-posterior direction.  
   
   
       39 . The intervertebral spacing implant of  claim 36 , wherein the spaced-apart recesses comprise opposing sidewalls disposed at a non-parallel angle with respect to each other.  
   
   
       40 . The intervertebral spacing implant of  claim 39 , wherein said angle is within a range of between approximately 45 degrees and 75 degrees.  
   
   
       41 . The intervertebral spacing implant of  claim 40 , wherein said angle is approximately 60 degrees.  
   
   
       42 . The intervertebral spacing implant of  claim 25 , wherein said spacing member further comprises attachment means for releasably attaching positioning means to said spacing member.  
   
   
       43 . The intervertebral spacing implant of  claim 42 , wherein said attachment means are positioned on an end of said spacing member opposite said free insertion end.  
   
   
       44 . The intervertebral spacing implant of  claim 42 ,. wherein said attachment means for releasably attaching positioning means to said spacing member comprises a recess in said spacing member.  
   
   
       45 . The intervertebral spacing implant of  claim 42 , wherein said attachment means for releasably attaching positioning means to said spacing member comprises a threaded bore.  
   
   
       46 . An intervertebral spacing implant comprising: 
 a spacing member adapted for implanting between adjacent vertebral bodies of a human spine as a load-bearing replacement for a spinal disc, said spacing member further comprising an external, concavo-convex contour with respect to one dimension of said spacing member;    wherein the spacing member defines an imaginary arcuate centerline residing between opposing sides of the external concavo-convex contour of said spacing member, said arcuate centerline forming less than half a circle, said spacing member further comprising an upper surface, a lower surface, and a sidewall extending around a perimeter of said spacing member between said upper surface and said lower surface, and wherein said sidewall has a smooth contour characterized by an absence of corners extending from said upper surface to said lower surface;    wherein the spacing member comprises a bone material.    
   
   
       47 . The intervertebral spacing implant of  claim 46 , wherein the spacing member is solid and is either inherently non-porous or is otherwise rendered non-porous.  
   
   
       48 . The intervertebral spacing implant of  claim 46 , wherein the spacing member is constructed from a rigid, non-resilient load-bearing material.  
   
   
       49 . The intervertebral spacing implant of  claim 46 , wherein the spacing member comprises a first end, a second end, and a length between said first end and said second end; 
 wherein said spacing member includes a tapered portion at said second end such that said spacing member becomes progressively thinner toward said second end of said spacing member;    wherein said tapered portion extends along a portion of said length such that said tapered portion covers less than approximately 25% of said length.    
   
   
       50 . The intervertebral spacing implant of  claim 46 , wherein said spacing member has a cashew shape having a uniform width along a majority length of the spacing member.  
   
   
       51 . The intervertebral spacing implant of  claim 46 , wherein the spacing member includes an anterior wall and a posterior wall, and wherein the external concavo-convex contour of the spacer is defined by the posterior wall being concave in a horizontal dimension and by the anterior wall being convex in a horizontal dimension.  
   
   
       52 . The intervertebral spacing implant of  claim 51 , wherein the anterior wall and the posterior wall of the spacing member are each linear in a vertical dimension.  
   
   
       53 . The intervertebral spacing implant of  claim 46 , wherein the concavo-convex contour comprises a concave posterior side, and a convex anterior side disposed in a substantially parallel orientation with respect to the concave posterior side.  
   
   
       54 . The intervertebral spacing implant of  claim 46 , wherein the spacing member further comprises a disc-like member having a thickness at a thickest part of the spacing member, and a length that is greater in length than said thickness at said thickest part, and a width that is greater in width than said thickness at said thickest part.  
   
   
       55 . The intervertebral spacing implant of  claim 54 , wherein the width of the spacing member is defined by a perimeter wall that constitutes the concave side and the convex side of the external concavo-convex contour of said spacing member.  
   
   
       56 . The intervertebral spacing implant of  claim 46 , wherein the spacing member further comprises a plurality of spaced-apart recesses formed in said upper surface.  
   
   
       57 . The intervertebral spacing implant of  claim 36 , wherein the recesses are elongate and are disposed in a substantially parallel orientation with respect to each other.  
   
   
       58 . The intervertebral spacing implant of  claim 57 , wherein the recesses extend in an anterior-to-posterior direction.  
   
   
       59 . The intervertebral spacing implant of  claim 56 , wherein the spaced-apart recesses comprise opposing sidewalls disposed at a non-parallel angle with respect to each other.  
   
   
       60 . The intervertebral spacing implant of  claim 59 , wherein said angle is within a range of between approximately 45 degrees and 75 degrees.  
   
   
       61 . The intervertebral spacing implant of  claim 60 , wherein said angle is approximately 60 degrees.  
   
   
       62 . The intervertebral spacing implant of  claim 46 , wherein said spacing member further comprises attachment means for releasably attaching positioning means to said spacing member.  
   
   
       63 . The intervertebral spacing implant of  claim 62 , wherein said attachment means are positioned on an end of said spacing member opposite a free insertion end.  
   
   
       64 . The intervertebral spacing implant of  claim 62 , wherein said attachment means for releasably attaching positioning means to said spacing member comprises a recess in said spacing member.  
   
   
       65 . The intervertebral spacing implant of  claim 62 , wherein said attachment means for releasably attaching positioning means to said spacing member comprises a threaded bore.  
   
   
       66 . A method of implanting an artificial intervertebral disc comprising: 
 (a) making an incision in an annulus of a human spinal column between adjacent vertebral bodies of said spinal column to thereby expose a space residing between said adjacent vertebral bodies;    (b) inserting a trial spacer through the incision and into position between the adjacent vertebral bodies, and evaluating a snugness of fit of said spacer as it resides between said adjacent vertebral bodies and determining a spacer size thereby; and    (c) inserting a spacing member, with a tapered end of said spacing member first, through the incision and into position between the adjacent vertebral bodies, and positioning said spacing member at an anterior location with respect to the spinal column such that more intervertebral space resides posteriorly to said spacing member than anteriorly thereto.    
   
   
       67 . The method of  claim 66 , wherein part (b) further comprises dislodging any unwanted soft tissue from between the vertebral bodies with the trial spacer.  
   
   
       68 . The method of  claim 66 , further comprising inserting said trial spacer through the incision in an arcuate path.  
   
   
       69 . The method of  claim 66 , further comprising applying compression to posterior portions of the adjacent vertebral bodies.  
   
   
       70 . A method of implanting an artificial intervertebral disc comprising: 
 (a) making an incision in an annulus of a human spinal column between adjacent vertebral bodies of said spinal column to thereby expose a space residing between said adjacent vertebral bodies;    (b) selecting a spacing member comprising an external concavo-convex contour with respect to one dimension of said spacing member, wherein said spacing member comprises a solid body, wherein said spacing member comprises an upper surface, a lower surface and a free insertion end, and wherein said spacing member includes a tapered portion such that said spacing member becomes progressively thinner toward said free insertion end of said spacing member; and    (c) inserting said spacing member, with said tapered portion of said spacing member first, through the incision and into position between the adjacent vertebral bodies, and positioning said spacing member at an anterior location with respect to the spinal column such that more intervertebral space resides posteriorly to said spacing member than anteriorly thereto.    
   
   
       71 . The method of  claim 70 , further comprising applying compression to posterior portions of the adjacent vertebral bodies.  
   
   
       72 . The method of  claim 70 , further comprising removing a natural human disc from the space.  
   
   
       73 . The method of  claim 70 , further comprising attaching an insertion instrument to said spacing member.  
   
   
       74 . The method of  claim 73 , wherein attaching an insertion instrument to said spacing member comprises threading a trocar on said spacing member.  
   
   
       75 . The method of  claim 71 , further comprising compressing the posterior portions of the adjacent vertebral bodies toward each other to a degree sufficient to move said adjacent vertebral bodies into a sagittal alignment.  
   
   
       76 . The method of  claim 75 , further comprising attaching a holding means to the adjacent vertebral bodies for holding said adjacent vertebral bodies in the sagittal alignment to thereby inhibit said vertebral bodies from moving out of sagittal alignment.  
   
   
       77 . The method of  claim 76 , wherein attaching holding means further comprises affixing pedicle screws to posterior pedicle portions of the vertebral bodies, and interconnecting rods with the pedicle screws.  
   
   
       78 . The method of  claim 70 , further comprising removing a posterior portion of one of the vertebral bodies for autogenous bone grafting.  
   
   
       79 . The method of  claim 70 , further comprising placing a lamina spreader between spinous processes to spread adjacent vertebral bodies apart.  
   
   
       80 . The method of  claim 70 , further comprising preparing a bone graft from autogenous bone graft material.  
   
   
       81 . The method of  claim 80 , further comprising harvesting autogenous bone and passing said autogenous bone through a mill to form said autogenous bone graft material.  
   
   
       82 . The method of  claim 70 , further comprising bringing the adjacent vertebral bodies closer together on a posterior side than on an anterior side.