Patent Publication Number: US-2006009846-A1

Title: Flexible systems for spinal stabilization and fixation

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application is a divisional of U.S. patent application Ser. No. 10/083,199 filed on Feb. 26, 2002, which is hereby incorporated by reference, which claims the benefit of the filing date of Provisional Patent Application No. 60/272,114 filed on Feb. 28, 2001. 
    
    
     BACKGROUND  
      The present invention is directed devices and methods for use in spinal surgery, and more particularly to devices and methods for stabilizing the spine.  
      Various spinal surgical procedures require access of a subject disc space or vertebral body, such as for the repair of a herniated disc or vertebral body, the insertion of one or more interbody fusion devices, interbody spacers, or artificial discs. In order to access a spinal column, one or more spinal ligaments and bony tissue may have to be severed or at least partially resected to allow insertion of devices and/or surgical instruments into or to the disc space or vertebral body. It also may be desirable to augment or replace existing spinal ligaments and bony tissue. Posterior or anterior rigid metal constructs can also be used to stabilize the spinal column after these techniques are completed.  
      Rigid metal plates or rods on the anterior, antero-lateral, lateral or posterior portions of the spinal column segment are in close contact with and exposed to the adjacent vasculature and tissue. It is desirable that the potential for screw back out, loosening, bending of the construct, and stress shielding be reduced or eliminated in view of this close contact with the vasculature and the surrounding tissue.  
     SUMMARY OF THE INVENTION  
      The present invention is directed systems and methods for spinal stabilization and fixation. The systems are useful in the replacement, reconstruction or augmentation of spinal ligamentous or bony tissues, and also in resisting the tensile and rotational loading applied thereto by spinal motion.  
      In one form, the spinal stabilization systems include at least an elongated implant configured to span the intervertebral disc space with its ends attached to a respective vertebral body. The ends of the implant can be placed in tunnels formed in the adjacent vertebrae. The implant can have a substantially flexible yet substantially inelastic body with a low profile capable of conforming to the spinal anatomy. The anchors used to attach the ends of the implant to the vertebrae can be at least partially concealed in the vertebral body to which it is engaged, further reducing the profile of the device. Examples of suitable anchors include interference screws, suture anchors, bone screws, buttons, pin fasteners, and staples. It is further contemplated that the implant and anchors can be made from nonresorbable or resorbable material.  
      In one technique, the stabilization system can be attached to and stabilize the anterior portion of the spinal column. The stabilization system can also be attached to and stabilize the lateral or antero-lateral portion of the spinal column. In another technique, the stabilization system is attached to a posterior portion of the spinal column via anchors engaged to the vertebrae at any one of a number of locations, including but not limited to the facets, pedicles, pars, transverse processes, or spinous processes.  
      There are also various methods for securing a flexible implant to adjacent vertebral bodies in which the anchor and at least a portion of the implant is placed in a tunnel formed in the vertebral body. The attachment techniques provide a low profile system that reduces exposure and contact with the adjacent anatomic structures.  
      These and other forms, aspects, embodiments, features and advantages of the present invention will be apparent from the following description of the illustrated embodiments.  
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       FIG. 1  is a side elevational view in partial section of a spinal column segment having an interbody fusion device inserted into the disc space and one embodiment spine stabilization system attached to the vertebral bodies.  
       FIG. 2  is a side elevational view in partial section of a spinal column segment having an artificial disc inserted into the disc space and another embodiment spine stabilization system attached to the vertebral bodies.  
       FIG. 3  is an anterior elevational view of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 4  is an anterior view of a spinal column segment having a further embodiment spine stabilization system attached thereto.  
       FIG. 5  is a side elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 6  is a side elevational view in partial section of a spinal column segment having a further embodiment spine stabilization system attached thereto.  
       FIG. 7  is a perspective view of one embodiment of an anchor for attaching spine stabilization systems to vertebral bodies.  
       FIG. 8  is a side elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 9  is a side elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 10  is a side elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 11  is a side elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 12  is an anterior elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 13  is an anterior elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 14  is a side elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 15  is a side elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 16  is an anterior elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 17  is an anterior elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 18  is an anterior elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 19  is an anterior elevational view in partial section of a spinal column segment having another embodiment spine stabilization system attached thereto.  
       FIG. 20  is a side elevational view of a spinal column segment having a posterior spine stabilization system attached thereto.  
       FIG. 21  is a side elevational view of a spinal column segment having another embodiment posterior spine stabilization system attached thereto.  
       FIG. 22  is a posterior elevational view of a spinal column segment having another embodiment posterior spine stabilization device attached thereto.  
    
    
     DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS  
      For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the illustrated embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any such alterations and further modifications of the invention, and any such further applications of the principles of the invention as illustrated herein are contemplated as would normally occur to one skilled in the art to which the invention relates.  
      The present invention includes spine stabilization systems in which flexible implants are anchored to the adjacent vertebrae. The stabilization systems have application in stabilizing the anterior, antero-lateral, lateral and/or posterior portions of a spinal column segment including one or more vertebral levels. The implants have a low profile and are conformable to the spinal anatomy to minimize intrusion into the surrounding tissue and vasculature. The implants attach to vertebrae and prevent separation of the vertebrae while allowing normal extension and articulation of the spinal column segment. Portions of the implants and the anchors attaching the implant to vertebrae can be at least partially or fully embedded within the vertebrae to minimize intrusion into the surrounding tissue and vasculature.  
      It is contemplated that the implants of the spine stabilization systems described herein can be made from resorbable material, nonresorbable material and combinations thereof. In one example, resorbable implants can be used with interbody fusion devices since a permanent exterior stabilization may not be desired after fusion of the vertebrae. It is also contemplated that the anchors used to attach the implants to the vertebrae can be made from resorbable material, nonresorbable material, and combinations thereof.  
      The implants can be flexible, tear resistant, and/or suturable. The implant can be fabricated from synthetic flexible materials in the form of fabrics, non-woven structures, two or three dimensional woven structures, braided structures, and chained structures. The implants can also be fabricated from natural/biological materials, such as autograft or allograft, taken from patellar bone-tendon-bone, hamstring tendons, quadriceps tendons, or Achilles tendons, for example. Growth factors or cells can be incorporated into the implant for bone ingrowth and bony attachment or for soft tissue ingrowth. Possible growth factors that can be incorporated include transforming growth factor β1, insulin-like growth factor 1, platelet-derived growth factor, fibroblast growth factor, bone morphogenetic protein, LIM mineralization protein (LMP), and combinations thereof.  
      Possible implant materials include synthetic resorbable materials such as polylactide, polyglycolide, tyrosine-derived polycarbonate, polyanhydride, polyorthoester, polyphosphazene, calcium phosphate, hydroxyapatite, bioactive glass and combinations thereof. Possible implant materials also include natural resorbable materials such as autograft, allograft, xenograft, soft tissues, connective tissues, demineralized bone matrix, and combinations thereof. Possible implant material further include nonresorbable materials such as polyethylene, polyester, polyvinyl alcohol, polyacrylonitrile, polyamide, polytetrafluorethylene, poly-paraphenylene terephthalamide, cellulose, shape-memory alloys, titanium, titanium alloys, stainless steel, and combinations thereof.  
      The spine stabilization systems described herein include anchors to attach the implant to the vertebrae. It is contemplated the anchors can be, for example, interference screws or anchors, gull anchors, suture anchors, pin fasteners, bone screws with spiked washers, staples, and buttons. It is contemplated that the anchors can be made from resorbable materials, nonresorbable materials, and combinations thereof. Possible synthetic resorbable materials include polylactide, polyglycolide, tyrosine-derived polycarbonate, polyanhydride, polyorthoester, polyphosphazene, calcium phosphate, hydroxyapatite, bioactive glass, and combinations thereof. Possible natural resorbable materials include cortical bone, autograft, allograft, and xenograft. Possible nonresorbable materials include carbon-reinforced polymer composites, shape-memory alloys, titanium, titanium alloys, cobalt chrome alloys, stainless steel, and combinations thereof.  
      Referring now to  FIG. 1 , there is shown a spine stabilization system attached to vertebrae V 1  and V 2 . Stabilization system  28  includes a flexible implant  30  that extends along the anterior faces of vertebrae V 1  and V 2 , and is attached to first vertebra V 1  and the second vertebra V 2 . A fusion device  34  has been inserted into disc space D for fusion of vertebra V 1  and vertebra V 2 . Implant  30  can resist extension, flexion, and/or lateral bending loads created by motion of the spinal column depending on the location or locations of the spinal column segment on which the implant is positioned.  
      Flexible implant  30  has a first end  31   a  and an opposite second end  31   b . Vertebra V 1  includes a first opening H 1  in its anterior face and a first tunnel extending therefrom. Vertebra V 2  has a second opening H 2  in its anterior face and a second tunnel extending therefrom. The ends  31   a  and  31   b  are inserted into respective ones of the first and second tunnels through openings H 1  and H 2 . An anchor  32   a  is inserted through opening H 1  and into the tunnel of vertebra V 1  to secure end  31   a  to vertebrae V 1 . Similarly, an anchor  32   b  is inserted through opening H 2  and into the tunnel of vertebra V 2  to secure end  31   b  to vertebrae V 2 . Anchors  32   a ,  32   b  are illustrated as threaded interference screws that are embedded into vertebral bodies V 1  and V 2  so that they do not protrude from the anterior faces of vertebrae V 1  and V 2 . However, as with the other implants discussed herein, other anchors and anchoring techniques described herein could also be employed with implant  30 .  
      Interference anchors  32   a ,  32   b  can be oriented at an angle ±α with respect to the axial plane P of spinal column that provides a smooth transition for implant  30  as it enters openings H 1  and H 2  of vertebrae V 1  and V 2 . This reduces stress concentrations at the junction between the implant and the vertebrae. In one embodiment, angle α is about 45 degrees. Other embodiments contemplate angular orientations that range from 0 degrees to about 80 degrees and from about 25 degrees to 65 degrees. As shown in  FIG. 3 , implant  30  has a reduced lateral width W 1  that minimizes the lateral intrusion of implant  30  into the surrounding tissue.  
      The ends of implant  30  and the other implants described herein can be provided with pigtails or other extensions of reduced size for insertion through the openings and tunnels formed in the vertebrae. It is also contemplated that the ends of the implant can include eyelets, holes, loops or other configuration suitable for engagement with an anchor.  
      Referring now to  FIG. 2 , a spine stabilization system  28 ′ similar to system  28  includes an implant  30  with opposite ends  31   a  and  31   b  attached to vertebra V 1  and V 2 , respectively. An artificial disc  38  is placed in disc space D. Implant ends  31   a  and  31   b  are attached to gull anchors  36   a  and  36   b , respectively. Gull anchors  36   a ,  36   b  are placed through respective ones of openings H 1  and H 2  and embedded in tunnels formed in vertebrae V 1  and V 2 , respectively, along with the corresponding ends  31   a ,  31   b  of implant  30 . Gull anchors  36   a ,  36   b  have wings that are pivotable toward their shaft of the anchor during insertion and are pivotable laterally away from the anchor shaft to resist pullout of the anchor from vertebra after insertion therein.  
      Referring now to  FIG. 4 , another embodiment spine stabilization system  40  is illustrated attached to vertebrae V 1  and V 2 . System  40  includes an implant  41  attached along the anterior faces of vertebrae V 1  and V 2 . Implant  41  has a width W 2  for attachment of two anchors to each end of implant  41 . The width W 2  also provides greater coverage of the annulus tissue surrounding disc space D. Anchors  44   a  and  44   b  are attached to comers  42   a  and  42   b,  respectively, of implant  41  to secure it to vertebra V 1 . Anchors  44   c  and  44   d  are attached to comers  42   c  and  42   d,  respectively, of implant  41  to secure it to vertebra V 2 .  
      Referring now to  FIGS. 5-7  there are shown two additional embodiments of a spinal stabilization system attached to vertebrae V 1  and V 2 . In  FIG. 5  stabilization system  50  includes an implant  51  extending along the anterior faces of vertebrae V 1  and V 2 . Implant  51  has a first end  52   a  attached to vertebra V 1  and an opposite second  52   b  attached to vertebra V 2 . Opening H 1  opens adjacent to or through the vertebral endplate of vertebra V 1 , and a first tunnel extends therefrom in vertebra V 1  to opening H 2  at its anterior face. First end  52   a  of implant  51  is placed into opening H 1  and through the tunnel and attached to vertebra V 1  with anchor  54   a  at opening H 2 . A second tunnel is formed in vertebra V 2  between opening H 3  adjacent to or through the vertebral endplate of vertebra V 2  and opening H 4  at its anterior face. Second end  52   b  of implant  51  is placed into opening H 3  and through the second tunnel and attached to vertebra V 2  with anchor  54   b  at opening H 4 .  
      In one embodiment, anchor  54  is a button or flange member that is secured to the ends of implant  51  and abuts against the anterior face of the respective vertebra. As shown in  FIG. 7 , anchor  54  has a bearing member  56  with a first flange  57  and an opposite second flange  58 . Flanges  57 ,  58  are sized larger than openings H 2 , H 4  and abut against the face of the vertebra around the respective opening in order to secure implant  51  to the vertebra.  
      In one embodiment, attachment loop  59  is attached to bearing member  56  to secure implant  51  thereto. Attachment loop  59  can extend into the tunnel adjacent the respective opening H 2 , H 4 . Implant  51  can be looped around attachment loop  59  as shown in  FIG. 7 , or attachment loop  59  can extend through the body of implant  51  like a suture. It is contemplated that attachment loop  59  can be, for example, a tether, cable, or wire. In another embodiment, not attachment loop is provided, but rather the ends of implant  51  extend through openings or slots provided in respective ones of the anchors  54   a,    54   b  and are secured thereto by tying, knotting, looping or otherwise fixing the ends of implant  51  to the adjacent anchor  54   a,    54   b.    
      In  FIG. 6  stabilization system  60  includes an implant  61  having a first end  62   a  attached to vertebra V 1  and an opposite second  62   b  attached to vertebra V 2 . A first tunnel is formed in vertebra V 1  between opening H 1  at the lower portion of the anterior face of vertebra V 1  and opening H 2  at the upper portion of the anterior face of vertebra V 1 . First end  62   a  of implant  61  is placed into opening H 1  and through the tunnel for attachment to vertebra V 1  with anchor  54   a  at opening H 2 . A second tunnel is formed in vertebra V 2  between opening H 3  at the upper portion of the anterior face of vertebra V 2  and opening H 4  at the lower portion of the anterior face of vertebra V 2 . Second end  62   b  of implant  61  is placed into opening H 3  and through the second tunnel for attachment to vertebra V 2  with anchor  54   b  at opening H 4 .  
      It is contemplated that implants  51 ,  61  or other implants described herein can be provided in multiple segments, of which each segment is attached to a respective one of the vertebrae V 1  and V 2 . The multiple implant segments can be attached to one another adjacent disc space D by suturing, stapling, fusing or otherwise securing the ends of the implant segments together to form a single implant  51 ,  61 . For example, implant  51  includes an upper segment  51   a  attachable to vertebra V 1  and a lower segment  51   b  attachable to vertebra V 2 . Upper segment  51   a  is attached to lower segment  51   b  at overlap region  51   c.    
      Referring now to  FIG. 8  another embodiment spine stabilization system  70  is attached to vertebrae V 1  and V 2 . System  70  has an implant  71  that extends between vertebrae V 1  and V 2 . Implant  71  has opposite ends  72   a  and  72   b  that are positioned in notches N 1  and N 2  formed in the anterior faces of vertebrae V 1  and V 2 , respectively. Implant  71  has first end  72   a  attached to vertebra V 1  via first anchor  74   a  in notch N 1 . Notch N 1  is formed in vertebra V 1  to recess the head of anchor  74   a  below the anterior face of vertebra V 1 , minimize or eliminating its protrusion into the adjacent tissue. Anchor  74   a  is illustrated in the form of a threaded screw that extends through a spiked washer  76   a . The screw and spikes of washer  76   a  extend through end  72   a  of implant  71  and into vertebra V 1 .  
      Implant  71  has opposite second end  72   b  attached to vertebra V 2  via second anchor  74   b  in notch N 2 . Notch N 2  is formed in vertebra V 2  to recess the head of anchor  74   b  below the anterior face of vertebra V 2 , minimizing or eliminating its protrusion into the adjacent tissue. Anchor  74   b  is illustrated in the form of a threaded screw that extends through a spiked washer  76   b.  The screw and spikes of washer  76   b  extend through end  72   b  and into vertebra V 2 .  
      Referring now to  FIG. 9  another embodiment spine stabilization system  80  is attached to vertebrae V 1  and V 2  with anchors  74   a ,  74   b . Anchors  74   a ,  74   b  include spiked washers  76   a ,  76   b  and a bone screw extending therethrough such as discussed above. System  80  has an implant  81  that extends along and is conformable to the anterior faces of vertebrae V 1  and V 2 . Implant  81  has a first end  82   a  attached to vertebra V 1  via first anchor  74   a . The screw and spikes of washer  76   a  extend through end  82   a  and into vertebra V 1  with the head of anchor  74   a  abutting against the anterior face of vertebra V 1 . Implant  81  has an opposite second end  82   b  attached to vertebra V 2  via second anchor  74   b . The screw and spikes of washer  76   b  extend through end  82   b  and into vertebra V 2  with the head of anchor  74   b  abutting against washer  76   b.    
      In one form, it is contemplated that the surface of washers  76   a ,  76   b  in contact with the head of the screw extending therethrough is concave to at least partially receive the screw head so that the profile of the screw head above washer  76   a  is minimized. In another form, the spiked washers are in the form of staples configured to attach the ends of the implant to the vertebrae without a bone screw.  
      Referring now to  FIG. 10 , another embodiment spine stabilization system  90  is shown attached to the anterior faces of vertebrae V 1  and V 2 . System  90  has an implant  91  having a first end  92   a  and an opposite second end  92   b  embedded in vertebrae V 1  and V 2 , respectively. Vertebra V 1  has a first opening H 1  and a first tunnel extending therefrom into vertebra V 1  at an angle +α relative to axial plane P of the spinal column. A second opening H 2  having a second tunnel extending therefrom is formed into vertebra V 1  at an angle +α relative to axial plane P so that the second tunnel intersects the first tunnel extending from opening H 1 . First end  92   a  is positioned through first opening H 1  and into the first tunnel where it is attached to vertebra V 1  by a first anchor  94   a.    
      Anchors  94   a,    94   b  are illustrated in the form of a pin fastener having a screw thread portion with a pin  95   a  extending therefrom. Anchor  94   a  is threaded into opening H 2  so that pin  95   a  extends through second end  92   a  to secure implant  91  to vertebra V 1 . The end of anchor  94   a  opposite pin  95   a  is provided without a head so that anchor  95   a  can be recessed below the anterior face of vertebra V 1 .  
      Vertebra V 2  has a third opening H 3  and a third tunnel extending therefrom at an angle −α into vertebra V 2 . A fourth opening H 4  having a fourth tunnel extending therefrom at an angle +α is formed in vertebra V 2  so that the fourth tunnel intersects the third tunnel extending from third opening H 3 . Second end  92   b  of implant  91  is positioned through third opening H 3  and into the third tunnel where it is attached to vertebra V 2  by a second anchor  94   b.  Anchor  94   b  has a screw thread with a pin  95   b  extending therefrom. Anchor  94   b  is threaded into opening H 4  so that pin  95   b  extends through second end  92   b  to secure implant  91  to vertebra V 2 . The end of anchor  94   b  opposite pin  95   b  is provided without a head so that anchor  95   b  can be recessed below the outer surface of vertebra V 2 .  
      Referring now to  FIG. 11 , implant  90  is shown with a slightly altered anchoring arrangement as compared to that of  FIG. 10 . The anchors  96   a ,  96   b  of  FIG. 11  are illustrated in the form of a pin fastener having an exposed head that extends slightly from the anterior face of vertebra V 1  and V 2 , respectively.  
      It is contemplated that the implant  91  of  FIGS. 10 and 11  can be provided with eyelet or other opening at each end  92   a ,  92   b  sized to receive the pin extending distally from the screw thread portion of anchors  94 ,  96 . It is also contemplated that the pins of anchors  94 ,  96  can extend directly through the implant material at its ends  92   a ,  92   b.    
      Referring now to  FIG. 12 , there is illustrated spine stabilization system  100  attached along the anterior faces of vertebrae V 1  and V 2 . System  100  has an implant  101  with a first end  102   a  and opposite second end  102   b . A first tunnel extends from first opening H 1  posteriorly into vertebra V 1 , and second tunnel extends laterally from a second opening H 2  formed in the lateral side of vertebra V 1  and intersects the first tunnel. First end  102   a  extends through opening H 1  and into the first tunnel. Anchors  104   a ,  104   b  are illustrated in the form of a pin fastener. A first anchor  104   a  has a screw thread portion with a pin  105   a  extending therefrom. First anchor  104   a  is placed through second opening H 2  so that pin  105   a  engages first end  102   a  of implant  101 .  
      A third tunnel extends from third opening H 3  posteriorly into vertebra V 2 , and a fourth tunnel extends laterally from a fourth opening H 4  formed in the lateral side of vertebra V 2  and intersects the third tunnel. Second end  102   b  extends through opening H 3  and into the third tunnel. A second anchor  104   b  has a screw thread portion with a pin  105   b  extending therefrom. Second anchor  104   b  is placed through fourth opening H 4  so that pin  105   b  engages first end  102   b  of implant  101 .  
      Referring now to  FIG. 13 , there is illustrated another embodiment spine stabilization system  110  extending along the anterior faces of vertebrae V 1 , V 2  and having an obliquely oriented attachment arrangement in each of the vertebrae V 1 , V 2 . System  110  includes an implant  111  extending between a first end  112   a  and a second end  112   b . First opening H 1  is formed in the anterior face of vertebra V 1  and has a first tunnel extending therefrom that curves obliquely relative to the sagittal plane toward the lateral face of vertebra V 1 . A second opening H 2  is formed in the antero-lateral face of vertebra V 1  and has a second tunnel extending therefrom that intersects the first tunnel. Implant  111  has a first end  112   a  extending through first opening H 1  into the first tunnel. A first anchor  114   a  has a screw thread portion with a pin  115   a  extending therefrom. Anchor  114   a  is placed through opening H 2  so that pin  115   a  engages first end  112   a  of implant  111 .  
      Third opening H 3  is formed in the anterior face of vertebra V 2  and has a first tunnel extending therefrom that curves obliquely relative to the sagittal plane toward the lateral face of vertebra V 2 . A fourth opening H 4  is formed in the antero-lateral face of vertebra V 2  and has a fourth tunnel extending therefrom that intersects the third tunnel. Implant  111  has a second end  112   b  extending through third opening H 3 . A second anchor  114   b  has a screw thread portion with a pin  115   b  extending therefrom. Anchor  114   b  is placed through opening H 4  so that pin  115   b  engages first end  112   b  of implant  111 .  
      Referring now to  FIG. 14  another embodiment spine stabilization system  120  is attached to vertebrae V 1  and V 2 . System  120  has an implant  121  extending along the lateral faces of vertebrae V 1  and V 2 . Vertebra V 1  has a first opening H 1  in the lateral face of vertebra V 1  and a first tunnel extending therefrom. First end  122   a  extends through first opening H 1  and into the first tunnel where anchor  124   a  secures implant  121  to vertebra V 1 . Vertebra V 2  has a second opening H 2  in the lateral face of vertebra V 2  and a second tunnel extending therefrom. Second end  122   b  extends through opening H 2  and into the second tunnel where second anchor  124   b  secures implant  121  to vertebra V 2 . Anchors  124   a ,  124   b  are interference screws embedded in the respective vertebrae V 1 , V 2  and in engagement with respective ones of the ends of implant  121 .  
      Referring now to  FIG. 15 , there is illustrated another embodiment spine stabilization system  130  having an implant  131  extending along the lateral faces of vertebrae V 1  and V 2 . First opening H 1  is formed in the lateral face of vertebra V 1  and has a first tunnel extending into vertebra V 1 . A second opening H 2  is formed in the anterior face of vertebra V 1  and has a second tunnel extending therefrom that intersects the first tunnel. Implant  131  has a first end  132   a  extending through first opening H 1  and into the first tunnel. A first anchor  134   a  in the second tunnel has a screw thread portion with a pin  135   a  extending therefrom that engages first end  132   a  of implant  131 .  
      Third opening H 3  is formed in the lateral face of vertebra V 2  and has a third tunnel extending therefrom into vertebra V 2 . A fourth opening H 4  is formed in the anterior face of vertebra V 2  and has a fourth tunnel extending therefrom that intersects the third tunnel. Implant  131  has a second end  132   b  extending through third opening H 3  into the third tunnel. A second anchor  134   b  in the fourth tunnel has a screw thread portion with a pin  135   b  extending therefrom that engages second end  132   b  of implant  131 .  
      Referring now to  FIGS. 16 and 17 , further embodiments of spine stabilization systems are illustrated that employ multiple implants attached to vertebra V 1  and V 2 . In  FIG. 16  stabilization system  140  includes a first implant  141  offset laterally to a first side of the sagittal plane L, and a second implant  141 ′ offset to a second side of the sagittal plane L. First and second implants  141 ,  141 ′ can be equally spaced the same distance from plane L.  
      First implant  141  has a first end  142   a  extending through opening H 1  and into a first tunnel formed in vertebra V 1 . First end  142   a  is attached to vertebra V 1  with anchor  144   a  in the first tunnel. Implant  141  has an opposite second end  142   b  extending through opening H 3  and into a third tunnel formed in vertebra V 2 . Second end  142   b  is attached to vertebra V 2  with anchor  144   b  in the third tunnel.  
      Second implant  141 ′ has a first end  142   a ′ extending through opening H 2  and into a second tunnel in vertebra V 1 . First end  142   a ′ is attached to vertebra V 1  with anchor  144   a ′ in the second tunnel. Implant  141 ′ has an opposite second end  142   b ′ extending through opening H 4  and into a fourth tunnel in vertebra V 2 . Second end  142   b ′ is attached to vertebra V 2  with anchor  144   b ′ in the fourth tunnel.  
      In  FIG. 17  stabilization system  150  is secured anteriorly to vertebrae V 1  and V 2 . System  150  has a first implant  151  with a first end  152   a  extending through opening H 1  and into a first tunnel formed in vertebra V 1 . First end  152   a  is attached to vertebra V 1  with anchor  154   a  in the first tunnel. Implant  151  has an opposite second end  152   b  extending across sagittal plane L and through opening H 4  and into a fourth tunnel formed in vertebra V 2 . Second end  152   b  is attached to vertebra V 2  with anchor  154   b  in the fourth tunnel.  
      Stabilization system  150  has a second implant  151 ′ with a first end  152   a ′ extending through opening H 2  and into a second tunnel formed in vertebra V 1 . First end  152   a ′ is attached to vertebra V 1  with anchor  154   a ′ in the second tunnel. Implant  151 ′ has an opposite second end  152   b ′ extending through opening H 3  and into a third tunnel formed in vertebra V 2 . Second end  152   b ′ is attached to vertebra V 2  with anchor  154   b ′ in the third tunnel. Second implant  151  ′ extends obliquely across sagittal plane L, forming an “X” shape with first implant  151 . The angle of each implant  151 ,  151 ′ relative to the sagittal plane may vary in the range from about 5 degrees to about 86 degrees, from about 20 degrees to about 70 degrees, and from about 30 degrees to about 60 degrees. The criss-crossing of implants  151 ,  151 ′ improves the resistance of spinal stabilization system  150  to relative rotation or lateral bending between vertebrae V 1  and V 2 .  
      Referring now to  FIG. 18  there is illustrated another embodiment of spinal stabilization system  160  attached to vertebrae V 1  and V 2 . System  160  has an implant  161  bendable or flexible to assume a U-shaped configuration, and is attachable to the anterior, antero-lateral or lateral faces of vertebrae V 1  and V 2 . A curved or non-linear tunnel is formed in vertebra V 1  between openings H 1  and H 2  in the anterior face of vertebra V 1 . Vertebra V 2  has formed therein a first tunnel extending from opening H 3 , and a second tunnel extending from opening H 4 . Implant  161  extends through the curved tunnel of vertebra V 1 , and has a first end  162   a  secured in the tunnel extending from opening H 3  with first anchor  164   a.  Implant  161  has a second end  162   b  secured in the tunnel extending from opening H 4  with second anchor  164   b.    
      Referring now to  FIG. 19  there is illustrated another spinal stabilization system  170  attached to vertebrae V 1  and V 2 . System  170  has an implant  171  bendable or flexible to assume an oval-shaped configuration, and is attachable to the anterior, antero-lateral or lateral faces of vertebrae V 1  and V 2 . A first curved or non-linear tunnel is formed in vertebra V 1  between openings H 1  and H 2  in the anterior face of vertebra V 1 . A second curved or non-linear tunnel is formed in vertebra V 2  between openings H 3  and H 4  in the anterior face of vertebra V 2 . Implant  171  extends through the first tunnel of vertebra V 1 , and has a first end  172   a  positioned in the second tunnel of vertebra V 2 . Implant  171  has a second end  172   b  positioned in the second tunnel adjacent to or in overlapping arrangement with first end  172   a . An anchor  174  secures ends  172   a ,  172   b  in the second tunnel of vertebra V 2 .  
      Referring now to  FIG. 20 , there is shown another embodiment stabilization system  180  secured to the posterior portion of the spine. System  180  has an implant  181  that extends between and is attached to the spinous processes SP 1  and SP 2  of vertebra V 1  and V 2  with anchors  184   a  and  184   b , respectively. Anchors  184   a  and  184   b  are illustrated as buttons or buckles such as described above with respect to button  54 . Tunnels can be drilled through each of the spinous processes SP 1 , SP 2  sized to receive the ends of implant  181  therethrough for attachment to anchors  184   a ,  184   b . Alternatively, the tunnels through SP 1  and SP 2  can be sized to receive an attachment loop or member extending from respective ones of the anchors  184   a ,  184   b  for engagement of the ends of implant  181  between SP 1  and SP 2 .  
      In  FIG. 21 , another embodiment posterior spine stabilization system  190  is illustrated. Vertebra V 1  includes a first tunnel formed in a pedicle thereof opening at H 1  on the pedicle at the posterior portion of the spinal column segment. Vertebra V 2  includes a second tunnel formed in or through a pedicle thereof and opening at H 2  on the pedicle at the posterior portion of the spinal column segment. System  190  includes an implant  191  extending between and attached to the pedicles P 1  and P 2  of vertebra V 1  and V 2 . Implant  191  includes a first end  191   a  embedded in the first tunnel in vertebra V 1  and attached thereto with anchor  194   a.  Implant  191  includes a second end  191   b  embedded in the second tunnel in vertebra V 2  and attached thereto with anchor  194   b . Anchors  194   a  and  194   b  are illustrated as threaded interference screws. However, other embodiments contemplate the use of other anchors described herein. Other embodiments also contemplate the attachment of posterior spine stabilization devices to the facets, pars, or transverse processes of vertebrae V 1  and V 2 .  
      Referring now to  FIG. 22 , a posterior view is provided of the posterior portion of the spinal column segment with a spine stabilization system  200  attached thereto along multiple levels. System  200  is similar to system  190  described above, and includes a first implant  201  attached to the pedicles of vertebrae V 1  and V 3  via anchors  204   a  and  204   c,  respectively, along one side of the spinous processes. The ends of implants  201  and anchors  204   a,    204   c  can be embedded or positioned in tunnels formed in the pedicles of vertebra V 1 , V 3 . Spine stabilization system  200  further includes a second implant  200 ′ attached to the pedicles of vertebrae V 1  and V 3  via anchors  204   a ′ and  204   c ′, respectively, along the other side of the spinous processes opposite implant  200 . The ends of implant  201 ′ and anchors  204   a ′,  204   c ′ can be embedded or positioned in tunnels formed in the pedicles of vertebra V 1 , V 3 . Implants  201 ,  201 ′ can span across vertebra V 2 , or can be attached thereto with an anchor extending through or coupled to the implant.  
      The present invention further contemplates surgical methods for attaching a spinal stabilization system to first and second vertebrae. The openings and tunnels can be formed by drilling, tapping, chiseling, punching, or otherwise cutting the vertebral bodies. In the embodiments of the stabilization system employing curved or non-linear tunnels through the vertebrae, it is contemplated that a flexible drill can be used to create these curved tunnels. It is further contemplated that attachment of the stabilization systems could occur before, after or during placement of a device into the disc space between the first and second vertebrae.  
      In one specific application, the stabilization system is used to reconstruct the anterior longitudinal ligament. In one specific surgical technique, the disc space is accessed from an anterior approach and a fusion device, artificial disc or spacer is inserted into the disc space. A first opening and tunnel is formed into the upper vertebral body and a second opening and tunnel is formed into the lower vertebral body. One end of the implant is inserted into either the first or second tunnel, and the implant is attached to the corresponding vertebra with an anchor. The opposite end of the implant is inserted into the other tunnel formed in the other vertebra and attached with an anchor. A desired tension can be applied to the implant before attachment of the other end to the other vertebra. The applied tension may differ depending on whether the device inserted into the disc space is a fusion cages, an artificial disc, or spacer. The other end of the implant is then attached to the other vertebra using a second anchor. The anchors can be embedded in the vertebrae to reduce the profile of the system along the upper and lower vertebrae.  
      While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the illustrated embodiments have been shown and described, and that all changes and modifications that come within the spirit of the invention are desired to be protected. For example, the spine stabilization system could be employed across multiple vertebral levels. In another example, multiple spine stabilization systems could be employed on the same vertebral level such as across the anterior aspects and the lateral aspects of the same vertebrae.