Apparatus and method for performing spinal surgery

Abstract

An embodiment of an intervertebral prosthetic device for implantation in a spine includes a rigid fixation member and a compressible member. The fixation member is configured to be placed in a cavity of a first vertebral body and against bone of the first vertebral body. The compressible member is configured to be placed in a cavity in an intervertebral disc and to be secured to the first fixation member. Another embodiment includes two compressible members and one fixation member. In this embodiment, the first and second compressible members are sized to substantially replace the nucleus pulposus of first and a second intervertebral discs, respectively, on either side of a vertebral body. The fixation member is sized to fit within a cavity in the vertebral body between the first and second compressible members.

1 . A prosthetic device comprising: 
 a first compressible member sized to substantially replace the nucleus pulposus of a first intervertebral disc;    a second compressible member sized to substantially replace the nucleus pulposus of a second intervertebral disc that is separated from the first intervertebral disc by a vertebral body; and    a fixation member sized to fit within a cavity in the vertebral body between the first and second compressible members.    
   
   
       2 . The prosthetic device according to  claim 1 , wherein the fixation member comprises: 
 at least one adjustable member configured to adjust a length of the fixation member; and    a locking mechanism configured to maintain the adjustable member at a fixed length.    
   
   
       3 . The prosthetic device according to  claim 2 , wherein the locking mechanism is a spacer.  
   
   
       4 . The prosthetic device according to  claim 1 , wherein each of the first and second compressible members comprises at least one of a spring, an elastomer, and disc allograft.  
   
   
       5 . The prosthetic device according to  claim 1 , wherein a plate of each of the first and second compressible members is configured to be positioned within a seat formed in an endplate of the vertebral body adjacent thereto.  
   
   
       6 . A prosthetic device comprising: 
 a fixation member sized to fit within a cavity in a first vertebral body; and    a compressible member sized to substantially replace a nucleus pulposus of an intervertebral disc adjacent the vertebral body,    wherein:    (A) a first side of the compressible member is configured to engage the fixation member and a second side of the compressible member is configured to engage a second vertebral body, and    (B) the second side of the compressible member is configured to fit within a seat formed in the cortical bone of the endplate of the second vertebral body.    
   
   
       7 . An intervertebral prosthetic device for implantation in a spine, comprising: 
 a rigid fixation member having a fixed length, the rigid fixation member being configured to be placed in a cavity of a vertebral body and against bone of the vertebral body; and    a first compressible member configured to be placed in a cavity in a first intervertebral disc adjacent the vertebral body and to be secured to the rigid fixation member,    wherein:    (A) the compressible member is constructed to remain compressible after implantation and has at least one compressible element that remains compressible after implantation, and    (B) the rigid fixation member is sized to compress the compressible member a predetermined amount when the rigid fixation member and the first compressible member are placed in the cavity in the first vertebral body and in the cavity in the first intervertebral disc, respectively.    
   
   
       8 . The intervertebral prosthetic device according to  claim 7 , further comprising: 
 a second compressible member,    wherein the second compressible member is configured to be:    (A) placed in a cavity in a second intervertebral disc adjacent the vertebral body on the opposite side as the first intervertebral disc; and    (B) secured to the rigid fixation member.    
   
   
       9 . The intervertebral prosthetic device according to  claim 8 , wherein the first and second compressible members are sized to replace the nucleus pulposuses of the first and second intervertebral discs, respectively.  
   
   
       10 . The intervertebral prosthetic device according to  claim 7 , wherein the rigid fixation member is composed of a bioresorbable material.  
   
   
       11 . The intervertebral prosthetic device according to  claim 7 , wherein the first compressible member has a plate opposite the rigid fixation member having a convex outer surface.  
   
   
       12 . The intervertebral prosthetic device according to  claim 11 , wherein the convex lowermost surface is configured to rest within a corresponding concave indentation formed in a second vertebral body adjacent thereto.  
   
   
       13 . An intervertebral prosthetic device for implantation in a spine comprising: 
 a fixation member configured to be placed in a cavity of a vertebral body, the fixation member comprising: 
 an outer member configured to be placed against bone of the vertebral body;  
 an inner member opposite the outer member; and  
 at least one adjustment element that extends between the outer and inner members and that is configured to adjust a length dimension of the fixation member along its longitudinal axis;  
   a compressible member configured to be placed in a cavity in an intervertebral disc adjacent the vertebral body and configured to be secured to the inner member of the fixation member; and    a spacer sized to fit between the outer and inner members of the fixation member to maintain the fixation member at a desired length dimension.    
   
   
       14 . The intervertebral prosthetic device according to  claim 13 , wherein the outer and inner members of the fixation member comprise outer and inner plates, respectively.  
   
   
       15 . The intervertebral prosthetic device according to  claim 14 , wherein the inner plate of the fixation member includes a notch through which a portion of the spacer extends.  
   
   
       16 . The intervertebral prosthetic device according to  claim 15 , wherein the portion comprises a peg.  
   
   
       17 . The intervertebral prosthetic device according to  claim 13 , wherein the spacer includes a peg.  
   
   
       18 . The intervertebral prosthetic device according to  claim 17 , wherein the compressible member includes a well dimensioned to receive the peg in a snap fit.  
   
   
       19 . The intervertebral prosthetic device according to  claim 13 , wherein the compressible member has a bottom plate with a convex lowermost surface.  
   
   
       20 . The intervertebral prosthetic device according to  claim 19 , wherein the convex lowermost surface is configured to rest within a corresponding concave indentation formed in a second vertebral body adjacent thereto.  
   
   
       21 . An intervertebral prosthetic device for implantation in a spine, comprising: 
 a fixation member configured to be placed in a cavity of a vertebral body, the fixation member comprising: 
 an outer member configured to be placed against bone of the vertebral body;  
 an inner member opposite the outer member; and  
 a longitudinal axis extending between the outer and inner members; and  
   a compressible member configured to be placed in a cavity in an intervertebral disc and to be secured to the inner member of the fixation member,    wherein:    (A) the compressible member is constructed to remain compressible after implantation, and    (B) the outer member includes a tab extending outward along an axis different from the longitudinal axis.    
   
   
       22 . The intervertebral prosthetic device according to  claim 21 , wherein the outer and inner members of the fixation member comprise outer and inner plates, respectively.  
   
   
       23 . The intervertebral prosthetic device according to  claim 21 , wherein the compressible member has a bottom plate with a convex lowermost surface.  
   
   
       24 . The intervertebral prosthetic device according to  claim 23 , wherein the convex lowermost surface is configured to rest within a corresponding concave indentation formed in a second vertebral body adjacent thereto.  
   
   
       25 . An intervertebral prosthetic device for implantation in a spine, comprising: 
 a fixation member configured to be placed in a cavity of a vertebral body, the fixation member comprising: 
 an outer member configured to be placed against bone of the vertebral body;  
 an inner member opposite the outer member; and  
 a longitudinal axis extending between the outer and inner members;  
   a compressible member configured to be placed in a cavity in an intervertebral disc adjacent the vertebral body and configured to be secured to the fixation member; and    at least one anchor element configured to immobilize and/or stabilize the compressible member and/or the fixation member.    
   
   
       26 . The intervertebral prosthetic device according to  claim 25 , wherein compressible member is constructed to remain compressible after implantation and has at least one compressible element that remains compressible after implantation.  
   
   
       27 . The intervertebral prosthetic device according to  claim 25 , wherein the anchor element is dimensioned to extend into at least one of the fixation member and the compressible member and through bone adjacent to at least one of the fixation member and the compressible member.  
   
   
       28 . An intervertebral prosthetic device according to  claim 25 , wherein the anchor element extends through bone adjacent the outer member of the fixation member and into the outer member.  
   
   
       29 . The intervertebral prosthetic device according to  claim 25 , wherein the compressible member has a bottom plate with a convex lowermost surface.  
   
   
       30 . The intervertebral prosthetic device according to  claim 29 , wherein the convex lowermost surface is configured to rest within a corresponding concave indentation formed in a second vertebral body adjacent thereto.  
   
   
       31 . A prosthetic device comprising: 
 a fixation member sized to fit within a cavity in a first vertebral body; and    a compressible member comprising: 
 a cup-shaped base member;  
 an upper member; and  
 one or more compressible elements provided between the base member and the upper member,  
 wherein the compressible member is sized to substantially replace a nucleus pulposus of an intervertebral disc adjacent the vertebral body.  
   
   
   
       32 . The prosthetic device according to  claim 31 , wherein the base member of the compressible member is configured to engage the fixation member and the upper member of the compressible member is configured to engage a second vertebral body.  
   
   
       33 . The prosthetic device according to  claim 31 , wherein the cup-shaped base member has a wall, and wherein one or more slots are provided in the wall.  
   
   
       34 . A prosthetic device comprising: 
 a fixation member sized to fit within a cavity in a first vertebral body; and    a compressible member comprising: 
 a base member;  
 an upper member that includes a spike; and  
 one or more compressible elements provided between the base member and the upper member,  
 wherein the one or more compressible elements are sized to substantially replace a nucleus pulposus of an intervertebral disc adjacent the vertebral body.  
   
   
   
       35 . The prosthetic device according to  claim 34 , wherein the base member of the compressible member is configured to engage the fixation member and the upper member of the compressible member is configured to engage a second vertebral body.  
   
   
       36 . A prosthetic device comprising: 
 a fixation member sized to fit within a cavity in a first vertebral body; and    a compressible member comprising: 
 a base member;  
 an upper member comprising a ball-and-socket joint; and  
 one or more compressible elements provided between the base member and the upper member,  
 wherein the compressible member is sized to substantially replace a nucleus pulposus of an intervertebral disc adjacent the vertebral body.  
   
   
   
       37 . The prosthetic device according to  claim 36 , wherein the upper member further comprises a plate supporting the ball-and-socket joint, and wherein the ball-and-socket joint comprises a spike.  
   
   
       38 . The prosthetic device according to  claim 36 , wherein: 
 (i) the base member of the compressible member is configured to engage the fixation member, and    (ii) the upper member of the compressible member is configured to engage a second vertebral body.    
   
   
       39 . The prosthetic device according to  claim 36 , wherein the ball-and-socket joint is configured to be fixed or to remain mobile upon implantation.  
   
   
       40 . A prosthetic device comprising: 
 a fixation member sized to fit within a cavity in a first vertebral body; and    a compressible member comprising: 
 a base member;  
 an upper member; and  
 one or more compressible elements provided between the base member and the upper member,  
 wherein:  
   (A) the compressible member is sized to substantially replace a nucleus pulposus of an intervertebral disc adjacent the vertebral body, and    (B) the base member is adjustable in a radial direction.    
   
   
       41 . The prosthetic device according to  claim 40 , wherein the base member is adjustable by means of a rotatable plate having a plurality of projections.  
   
   
       42 . The prosthetic device according to  claim 41 , wherein when the rotatable plate rotates, the projections engage and radially extend a plurality of extendable leaves.  
   
   
       43 . A method of spinal prosthetic implantation, the method comprising the step of: 
 creating a cavity in a first vertebral body;    cutting a first hole through either a lower or an upper endplate of the vertebral body and through the nucleus pulposus of a first intervertebral disc adjacent thereto, thereby creating a first opening in the first intervertebral disc;    cutting a second hole through the other of the lower and upper endplate of the vertebral body and through the nucleus pulposus of a second intervertebral disc adjacent thereto, thereby creating a second opening in the second intervertebral disc;    implanting a first compressible member into one of the first and second openings;    implanting a second compressible member into the other of the first or second openings; and    implanting a fixation member into the cavity in the first vertebral body.    
   
   
       44 . The method according to  claim 43 , further comprising the step of adjusting a length of the fixation member.  
   
   
       45 . The method according to  claim 43 , further comprising the step of creating a first seat in an endplate of a second vertebral body below the first vertebral body.  
   
   
       46 . The method according to  claim 45 , further comprising the step of creating a second seat in an endplate of a third vertebral body above the first vertebral body, wherein each of the first and second seats is configured to receive a respective one of the first and second compressible members.  
   
   
       47 . The method according to  claim 43 , further comprising the step of positioning, in the fixation member, at least one of bone allograft, bone cement, and a bioresorbable polymer.  
   
   
       48 . The method according to  claim 43 , wherein the step of implanting a first compressible member into one of the first and second opening comprises providing a plurality of compressible elements in the first compressible member, wherein the plurality of compressible elements vary in a degree to which they are compressible.  
   
   
       49 . The method according to  claim 43 , wherein: 
 (i) the first compressible member comprises a base member that is wider than the hole cut in the vertebral body through which the first compressible member is implanted, and    (ii) the step of implanting the first compressible member into one of the first and second openings comprises the steps of: (a) maneuvering the base member of the first compressible member so that it passes through the hole in the one of the first and second openings; and (b) rotating the base member so that it substantially covers the hole.    
   
   
       50 . The method according to  claim 43 , wherein: 
 (i) the first compressible member comprises a base member that is radially adjustable to be wider than the hole cut in the vertebral body through which the first compressible member is implanted, and    (ii) the step of implanting the first compressible member into one of the first and second openings comprises the steps of: (a) maneuvering the base member of the first compressible member so that it passes through the hole in the one of the first and second openings; and (b) radially expanding the base member so that it substantially covers the hole.    
   
   
       51 . A method of spinal prosthetic implantation, the method comprising the steps of: 
 creating a cavity in a first vertebral body;    cutting through an endplate of the vertebral body and through the nucleus pulposus of an adjacent intervertebral disc, thereby creating an opening in the intervertebral disc;    cutting into the cortical bone of a second vertebral body on the other side of the intervertebral disc to create a seat;    implanting a compressible member into the opening in the intervertebral disc such that a distal end of the compressible member sits within the seat in the second vertebral body; and    implanting a fixation member in the cavity in the first vertebral body.    
   
   
       52 . The method according to  claim 51 , further comprising the step of adjusting a length of the fixation member.  
   
   
       53 . A method of spinal prosthetic implantation, the method comprising the step of: 
 creating a cavity in a vertebral body;    cutting a hole through either a lower or an upper endplate of the vertebral body and through the nucleus pulposus of an intervertebral disc adjacent thereto, thereby creating an opening in the intervertebral disc;    implanting a compressible member into the opening in the intervertebral disc; and    implanting a fixation member into the cavity in the first vertebral body,    wherein:    (i) the compressible member comprises a base member that is wider than the hole cut in the vertebral body through which the first compressible member is implanted, and    (ii) the step of implanting the compressible member into the opening comprises the steps of: (a) maneuvering the base member of the compressible member so that it passes through the hole and into the opening; and (b) rotating the base member so that it substantially covers the hole.    
   
   
       54 . The method according to  claim 53 , further comprising the step of creating a seat in an endplate of a second vertebral body on the other side of the intervertebral disc in which the opening is formed.  
   
   
       55 . A method of spinal prosthetic implantation, the method comprising the step of: 
 creating a cavity in a vertebral body;    cutting a hole through either a lower or an upper endplate of the vertebral body and through the nucleus pulposus of an intervertebral disc adjacent thereto, thereby creating an opening in the intervertebral disc;    implanting a compressible member into the opening in the intervertebral disc; and    implanting a fixation member into the cavity in the first vertebral body,    wherein:    (i) the compressible member comprises a base member that is radially adjustable to be wider than the hole cut in the vertebral body through which the compressible member is implanted, and    (ii) the step of implanting the compressible member into the opening comprises the steps of: (a) maneuvering the base member of the compressible member so that it passes through the hole and into the opening; and (b) radially adjusting the base member so that it substantially covers the hole.    
   
   
       56 . The method according to  claim 55 , further comprising the step of creating a seat in an endplate of a second vertebral body on the other side of the intervertebral disc in which the opening is formed.  
   
   
       57 . A drill guide for use in spinal surgery, comprising a body having a first leg and a second leg, wherein: 
 (A) the first leg is dimensioned to be fixed relative to an intervertebral prosthetic member mounted in a cavity of a first vertebral body,    (B) the second leg is dimensioned to extend from the first leg, adjacent the first vertebral body, to a free end, adjacent at least one of an intervertebral disc and a second vertebral body, and    (C) the second leg includes at least one drilling channel extending through the second leg and the free end of the second leg comprises a drill positioning block through which the at least one drilling channel extends.