Abstract:
A spinal implant for immobilizing the C1 vertebra with respect to the C2 vertebra of the spine provides controlled coupling between the C1 and C2 vertebrae, and includes a C1 component attachable to the C1 vertebra, two C2 components attachable to the C2 vertebra, and a transverse element. The C1 component has two wings each of which retains a rod holder that rotates and translate for capturing a C2 component rod. Each C2 component has a hook for connection with a side of the C2 vertebra lamina and a rod for attachment to one of the rod holders of the C1 component. Each C2 component receives and secures the transverse connector which holds position of the C2 components relative to one another. Each C2 component may include a plate configured for compression against the C2 vertebra spinous process, with each plate including spikes to aid in preventing construct migration.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 14/596,849 filed on Jan. 14, 2015, which claims the benefit of and/or priority under 35 U.S.C. §119(e) to U.S. Application No. 61/927,095 filed on Jan. 14, 2014 and titled “Implant For Immobilizing Cervical Vertebrae”; the entire contents of all of which are incorporated herein by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    The present disclosure relates to devices for immobilizing vertebrae of the spine and, more particularly, to devices for immobilizing the C1 vertebra with respect to the C2 vertebra of the spine. 
       BACKGROUND 
       [0003]    Because of various circumstances such as injury, trauma, degeneration or the like, it becomes necessary to immobilize one or more vertebrae with respect to other vertebrae of the spine. This includes vertebrae of the lumbar, thoracic and the cervical areas. Various devices have been devised in order to accomplish this result. 
         [0004]    While these devices are adequate to immobilize lumbar vertebrae, thoracic vertebrae, and some of the cervical vertebrae of the spine, they are particularly deficient in effectively immobilizing the C1 cervical vertebra relative to the C2 cervical vertebra. The C1 or atlas vertebra is the topmost cervical vertebra of the human spine and, along with the C2 or axis vertebra forms the joint connecting the skull and spine. A major difference of the atlas cervical vertebra relative to other vertebrae is that it does not have a body but is fused with the C2 vertebra. The C2 vertebra forms the pivot upon which C1 rotates. It is because of these peculiarities that prior art vertebral immobilization devices are inadequate for use with a C1 to C2 immobilization. 
         [0005]    In view of the above, it can be appreciated that it would be desirable to have a better device, method and manner of immobilizing the C1 vertebra to the C2 vertebra. 
         [0006]    The present invention sufficiently accomplishes these means. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is a spinal implant for immobilizing the C1 vertebra with respect to the C2 vertebra of the spine. The immobilization implant provides controlled coupling between the C1 and C2 vertebrae. 
         [0008]    The immobilization implant includes a C1 component configured for attachment to the C1 vertebra, two C2 components each configured for attachment to the C2 vertebra, and a transverse element. 
         [0009]    The C1 component can have a singular hook configured for placement midline on the C1 vertebra or multiple hooks configured for placement on multiple areas of the C1 vertebra. The arms and/or hook(s) are capable of being bent and translated to a desired position. The C1 component has two arms that each retains a rod holder which is configured to rotate and translate with respect to its respective arm for capturing a rod from each C2 component. This allows the device to accommodate varying anatomy. 
         [0010]    In one form, the rod holder of each arm is retained in a slot in the upper surface of the respective arm. This allows each rod holder to translate along the respective arm in the cephalad-caudal direction. Rotation of each rod holder is fixed through interaction between structures on the bottom outside surface of the rod holder and structures beneath the bottom outside surface of the rod holder within the slot. In a particular instance, and without being limiting, such structures may be serrations, teeth or the like. Downward pressure exerted on the rod holder causes the two structures to mesh and lock. Other manners of fixing rotation of the rod holder may be used. 
         [0011]    In another form, the rod holder of each arm is retained in a slot in the side surface of the respective arm. This allows each rod holder to translate along the respective side arm in the cephalad-caudal direction. Rotation of each rod holder is fixed through interaction between structures on the lower outside surface of the rod holder and structures adjacent the lower outside surface of the rod holder within the slot. In a particular instance, and without being limiting, such structures may be serrations, teeth or the like. Downward pressure exerted on the rod holder causes the two structures to mesh and lock. Other manners of fixing rotation of the rod holder may be used. 
         [0012]    The underside of the C1 hook may be configured to provide stable securing of the C1 hook at its implanted position after the surgeon releases the implant instrumentation therefrom. This feature may be embodied as spring-loaded serrated teeth that projects from the C1 hook. The serrated teeth are angled and thus retained within the hook such that the serrated teeth recess into the hook during insertion and positioning of the C1 hook on the lamina of (or other relevant anatomy) at the particular level (e.g. C1), then is biased against the lamina of (or other relevant anatomy) by its spring-loading to help keep the hook in the same position at which it was intended. 
         [0013]    Each C2 component has a body with a hook for connection with a side of the C2 vertebra lamina and a rod for attachment to one of the rod holders of the C1 component. Each C2 component is also configured to receive and secure the transverse connector or element that holds a position of the C2 components relative to one another. The transverse element runs caudally to the C2 spinous process. In one form, the body of each C2 component is integrated with a plate that is configured to be compressed against the C2 vertebra spinous process. Each plate includes projecting spikes to aid in preventing migration of the construct once installed. 
         [0014]    In one form, the transverse element may include integrated connectors configured to connect the C1/C2 construct (the present spinal implant) to an occipital rod that connects the occiput to the cervical/thoracic region. 
         [0015]    The present spinal implant may also be used with respect to the immobilization of vertebrae other than the C1/C2 vertebrae such as the other cervical vertebrae, the thoracic vertebrae, and the lumbar vertebrae. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above mentioned and other features of this invention, and the manner of attaining them, will become apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0017]      FIG. 1  is a view of a device for immobilizing a C1 vertebra of the spine relative to a C2 vertebra of the spine fashioned in accordance with the principles of the present invention; 
           [0018]      FIG. 2  is a view of one of two C2 components of the cervical vertebrae immobilization device of  FIG. 1 ; 
           [0019]      FIG. 3  is another view of the C2 component of  FIG. 2 ; 
           [0020]      FIG. 4  is a view of a C1 component of the cervical vertebrae immobilization device of  FIG. 1 ; 
           [0021]      FIG. 5  is an enlarged partial view of the C1 component of  FIG. 4 ; 
           [0022]      FIG. 6  is another view of the C1 component of  FIG. 4 ; 
           [0023]      FIG. 7  is another view of the C1 component of  FIG. 4 ; 
           [0024]      FIG. 8  is a view of the cervical vertebrae immobilization device of  FIG. 1  installed on the C1 and C2 vertebrae of the spine; 
           [0025]      FIG. 9  is another view of the cervical vertebrae immobilization device of  FIG. 1  installed on the C1 and C2 vertebrae of the spine; 
           [0026]      FIG. 10  is a view of the cervical vertebrae immobilization device of  FIG. 1  installed on the C1 and C2 vertebrae of the spine and having an additional transverse element thereon for connecting the cervical immobilization device to an occipital rod; 
           [0027]      FIG. 11  is a view of another cervical vertebrae immobilization device fashioned in accordance with the principles of the present invention; 
           [0028]      FIG. 12  is an underside view of the cervical vertebrae immobilization device of  FIG. 11 ; 
           [0029]      FIG. 13  is an end view of the cervical vertebrae immobilization device of  FIG. 11 ; 
           [0030]      FIG. 14  is another view of the cervical vertebrae immobilization device of  FIG. 11 ; 
           [0031]      FIG. 15  is a top view of the cervical vertebrae immobilization device of  FIG. 11 ; and 
           [0032]      FIG. 16  is an end view of the cervical vertebrae immobilization device of  FIG. 11 . 
       
    
    
       [0033]    Although the drawings represent embodiments of various features and components according to the present invention, the drawings are not necessarily to scale and certain features may be enhanced in order to better illustrate and explain the present invention. The exemplifications set out herein thus illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION 
       [0034]    Those of skill in the art will understand that various details of the invention may be changed without departing from the spirit and scope of the invention. Furthermore, the foregoing description is for illustration only, and not for the purpose of limitation. 
         [0035]    Referring to the figures and in particular,  FIG. 1 , there is depicted an exemplary embodiment of an implant or device, generally designated  10 , for immobilizing vertebrae of the spine and particularly, but not necessarily, the cervical vertebrae of the spine and, more particularly, but not necessarily, a C1 (atlas) vertebra of the spine relative to a C2 (axis) vertebra of the spine fashioned in accordance with the present principles. Thus, while the present vertebral immobilization implant  10  is shown and described herein with respect to the C1 and C2 vertebrae of the spine, it should be appreciated that the vertebral immobilization implant  10  may be used with other vertebrae of the spine. Additionally, as described further below, the vertebral immobilization implant  10  allows connection to other vertebral implants if desired. 
         [0036]    As seen in  FIG. 1 , in general, the vertebral immobilization implant  10  has a C1 component  12  configured to attach to the C1 vertebra, and two C2 components  14   a ,  14   b  each one configured to attach to the C2 vertebra. Particularly, the C1 component  12  is attached to the posterior arch of the C1 vertebra, while each C2 component  14   a ,  14   b  attaches to the vertebral body of C2 on opposite sides of its spinous process (see, e.g.  FIGS. 8-10 ). A transverse element or connector, shown in the form of a rod  70 , is provided between and captured by the two C2 components  14   a ,  14   b . The transverse element  70  allows the position of the C2 components to be fixed relative to one another and to aid in securing each C2 component by compression to respective sides of the C2 spinous process. 
         [0037]      FIG. 4  shows the C1 component  12 . The C1 component  12  is made from a biocompatible material such as, but not limited to, stainless steel or titanium. The C1 component  12  is defined by a body  16  having first and second arms, wings, extensions or the like (arms)  20   a ,  20   b  that project from a generally central head  18 , the nomenclature first and second being arbitrary here and throughout unless otherwise indicated. Each arm  20   a ,  20   b  is generally paddle or ovoid-shaped but may take different forms if desired. A channel, groove, concavity, depression or the like  21  separates the first and second arms  20   a ,  20   b . As depicted in  FIG. 4 , each arm  20   a ,  20   b  project outwardly and generally downward. Each arm however, may be angled as desired relative to the head  18 . This is particularly illustrated in the position of the arms  20   a ,  20   b  in  FIGS. 6 and 7 . Angling the arms  20   a ,  20   b  provides a better fit on the C1 vertebra. 
         [0038]    Referring back to  FIG. 4 , the first arm  20   a  includes a recess, cutout or the like (recess)  22   a  that extends in and along an upper surface of the arm  20   a . A first holder  24   a  is positioned within the recess  22   a . The first holder  24   a  is rotatable within the recess  22   a  and thus relative to the arm  20   a . The rotational position of the first holder  24   a  is fixed through interaction of the bottom area of the first holder  24   a  with a first fixation structure  23   a  within the recess  22   a . The first fixation structure  23   a  is illustrated as a first ring of teeth, notches, serrations or the like (teeth) with the bottom area of the first holder  24   a  configured with a like ring of teeth. The first holder  24   a  may also translate within the recess  22   a.    
         [0039]    The first holder  24   a  is generally U-shaped and thus defines a slot between first and second cupped sides  25   a ,  27   a . The slot of the first holder  24   a  is configured to receive a bar or rod  44   a  of the C2 component  14   a . The first side  25   a  has threading  28   a  on the inside cupped surface thereof, with the second side  27   a  also having threading  26   a  on the inside surface thereof. The internal threading  26   a ,  28   a  is configured to receive a threaded set screw  90  for securing the bar  44   a  of the C2 component. 
         [0040]    The second arm  20   b  includes a recess, cutout or the like (recess)  22   b  that extends in and along an upper surface of the arm  20   b . A second holder  24   b  is positioned within the recess  22   b . The second holder  24   b  is rotatable within the recess  22   b  and thus relative to the arm  20   b . The rotational position of the second holder  24   b  is fixed through interaction of the bottom area of the second holder  24   b  with a second fixation structure  23   b  within the recess  22   b . The second fixation structure  23   b  is illustrated as a second ring of teeth, notches, serrations or the like (teeth) with the bottom area of the second holder  24   b  configured with a like ring of teeth. The second holder  24   b  may also translate within the recess  22   b.    
         [0041]    The second holder  24   b  is generally U-shaped and thus defines a slot between first and second cupped sides  25   b ,  27   b . The slot of the second holder  24   b  is configured to receive a bar or rod  44   b  of the C2 component  14   b . The first side  25   b  has threading  28   b  on the inside cupped surface thereof, with the second side  27   b  also having threading  26   b  on the inside surface thereof. The internal threading  26   b ,  28   b  is configured to receive a threaded set screw  90  for securing the bar  44   b  of the C2 component. 
         [0042]    As seen in  FIGS. 4 and 5 , the C1 component  12  has a hook structure  29  extending from the underside of the head  18 . The hook  29  has a generally planar tongue  30  that defines a recess  31 . The hook  29  is configured to attach to and around the posterior arch of the C1 vertebra and, particularly, the posterior arch of the C1 vertebra is received in the recess  31  of the hook  29  with the tongue extending under the C1 posterior arch, and more particularly midline on the C1 vertebra. The hook  29  is configured to be bent at various angles to accommodate varying C1 anatomy. 
         [0043]    The underside of the hook  29  is configured to provide stable securement of the hook  29  at its implanted position after it is released from the implant instrumentation. While not being limiting, in one form, this feature is embodied as spring-loaded serrated teeth  33  that projects from a recess  32  on the underside of the hook  29 . The serrated teeth  33  are angled and thus retained within the recess  32  such that the serrated teeth  33  recede into the head  18  during insertion and positioning of the hook  29  on the lamina of the C1 vertebra. The teeth  33  are then biased against the lamina of by its spring-loading in order to help keep the hook in the same position at which it was intended. 
         [0044]      FIGS. 2 and 3  particularly show the first C2 component  14   a . The second C2 component  14   b  is a mirror image of the first C2 component. As such the second C2 component will not be discussed in detail since its features, components and configuration are the same as the first C2 component, the numerical labeling of which ends in a “b”. The first C2 component  14   a  has a body  40   a  that defines a plate  42   a  having an angled front face  58   a  and an angled rear face  62   a , the nomenclature front and rear being arbitrary. The front face  58   a  is generally planar. The rear face  62   a  is generally planar with a plurality of spikes, projections or the like (spikes)  63   a  extending outwardly therefrom. The rear face  68   a  is angled to follow the contour or angling of a side of the spinous process SP (see, e.g.,  FIGS. 8-10 ). The spikes  63   a  are configured to grip the side of the spinous process SP. A bore  59   a  extends through the plate  42   a  from the front face  58   a  to the rear face  68   a . The bore  59   a  accepts a bone screw or other fastener (not shown) in order to positively secure the plate  42   a  to the side of the spinous process SP if desired. 
         [0045]    The body  40   a  further has a rod, shaft, pole or the like (rod)  44   a  that projects outwardly from a side  45   a  of the plate  42   a . The rod  44   a  is configured to be received in the first holder  24   a  of the C1 component (see, e.g.,  FIGS. 8-10 ). The rod  44   a  also has a length that allows the first holder  24   a  of the C1 component to receive and retain the rod  44   a  at various longitudinal positions along the rod, thereby providing length adjustment between the C1 component/C1 vertebra and the first C2 component/C2 vertebra and/or a side of the spinous process SP. This accommodates variations in anatomy (i.e. spacing between the C1 vertebra and the C2 vertebra). 
         [0046]    The body  40   a  moreover has a rod holder  50   a  that extends from an end of the plate  42   a  opposite the end  45   a  and offset from a longitudinal axis of the rod  44   a . The rod holder  50   a  has a front portion  54   a  that extends outward from and generally perpendicular to the side of the plate  42   a . The front portion  54   a  has threading  55   a  on an inside surface. The rod holder  50   a  further includes a rear portion  52   a  that extends from the bottom of the front portion  54   a  such that the rod holder  50   a  is generally cupped shaped and defines a rod holder area therein and between the front and rear portions  54   a ,  52   a . The rear portion  52   a  has threading  53   a  on an inside surface facing the threading  55   a  of the front portion  54   a . The threading  53   a ,  55   a  is configured to receive a set screw  90  or the like (see, e.g.,  FIGS. 8-10 ). 
         [0047]    A hook  46   a  extends from a bottom of the rod holder  50   a  and defines a hook area  47   a . The hook  46   a  is configured to attach onto and extend under a portion of the lamina of the C2 vertebra adjacent one side (first side) of the spinous process SP thereof (see, e.g.  FIGS. 8-10 ). Particularly, as discerned in  FIGS. 8-10 , the first C2 component  14   a  is designed to hook or grasp onto and/or around the inferior end of the C2 lamina. 
         [0048]    As indicated above, the second C2 component  14   b  is a mirror configuration of the C1 component  14   a . Thus, while the first C2 component  14   a  is configured to connect to the left side of the C2 vertebra and extend to the left side of the C1 vertebra, the second C2 component  14   b  is configured to connect to the right side of the C2 vertebra and extend to the right side of the C1 vertebra. The rod  44   a  of the first C2 component  14   a  is received in the rod holder  24   a  of the C1 component  12  while the rod  44   b  of the second C2 component  14   b  is received in the rod holder  24   b  of the C1 component. 
         [0049]      FIGS. 8 and 9  particularly show various views of the present vertebral immobilization implant  10  situated, implanted on, or otherwise attached to and between the C1 vertebra and the C2 vertebra. The vertebral immobilization implant  10  stabilizes the C1 and C2 vertebrae relative to one another. 
         [0050]      FIG. 10  shows a variation of the present implant  10  wherein the transverse element  70  has been replace with a transverse element assembly  80  for connecting the present implant  10  to one or more occipital rods that connect the occiput to the cervical/thoracic region of the spine. The transverse element assembly  80  includes a rod  81  that is configured to be received in the first and second rod holders  50   a ,  50   b  of the respective first and second C2 components  14   a ,  14   b . A first rod holder (integrated connector)  82   a  is provided on a first end of the rod  81  and is configured to receive a connecting rod (not shown). A second rod holder (integrated connector)  82   b  is provided on a second end of the rod  81  and is configured to receive another connecting rod (not shown). The rod holders  82   a ,  82   b  are configured to each receive a threaded set screw  90 . Other configurations and/or manners of providing this connection are contemplated. 
         [0051]    Referring to  FIGS. 11-16 , there is shown another exemplary embodiment of an implant or device, generally designated  100 , for immobilizing vertebrae of the spine in like manner and function and to the implant  10 . In general, the vertebral immobilization implant  100  has a C1 component  112  configured to attach to the C1 vertebra, and two C2 components  114   a ,  114   b  each one configured to attach to the C2 vertebra. Particularly, the C1 component is attached to the posterior arch of the C1 vertebra, while each C2 component  114   a ,  114   b  attaches to the vertebral body of C2, preferably, but not necessarily, on opposite sides of its spinous process (see, e.g.  FIGS. 8-10 ). A transverse element or connector, shown in the form of a rod  170 , is provided between and captured by the two C2 components  114   a ,  114   b . The transverse element  170  allows the position of the C2 components  114   a ,  114   b  to be fixed relative to one another and to aid in securing each C2 component by compression to respective sides of the C2 spinous process. 
         [0052]    The C1 component  112  is made from a biocompatible material such as, but not limited to, stainless steel or titanium. The C1 component  112  is defined by a body  116  having first and second arms, wings, extensions or the like (arms)  117   a ,  117   b , the nomenclature first and second being arbitrary here and throughout unless otherwise indicated. Each arm  117   a ,  117   b  is generally paddle or ovoid-shaped but may take different forms if desired. A lower notch  118   a  is formed at the bottom of the body  116  between the first and second arms  117   a ,  117   b . A first upper notch is formed at the top of the body  116  adjacent the first arm  117   a , while a second upper notch is formed at the top of the body  116  adjacent the second arm  117   b . Each arm  117   a ,  117   b  project outwardly and generally downward. Each arm however, may be angled as desired relative to the head  18 . 
         [0053]    As best seen in  FIG. 11 , the first arm  117   a  includes a slot or the like  119   a  that extends in and along the side of the first arm  117   a . A first adjustable element  120   a  is retained in the slot  119   a  so as to be translatable (movable) along the length of the slot  119   a  (in the medial-lateral direction or transverse plane) and rotatable relative thereto. As such, the first adjustable element  120   a  is rotatable relative to the first arm  117   a . A weld plate  140   a  ensures that a hook  121   a  of the first adjustable element  120   a  does not disassociate from the body  116 /arm  117   a . The weld plate  120   a  also ensures that the translation of the first adjustable element remains parallel with the medial-lateral (transverse) plane and does not travel obliquely. 
         [0054]    The first adjustable element  120   a  includes a generally U-shaped rod holder  121   a  defining a slot between two cupped sides, the slot configured to receive the rod ( 134   a ,  134   b ) of a C2 component ( 114   a ,  114   b ). While not seen, the two cupped sides have threading on the inside cupped surface thereof. The internal threading is configured to receive a threaded set screw  90  for securing the rod of the C2 component. 
         [0055]    The first adjustable element  120   a  also includes a hook  122   a  extending from the underside of the rod holder  121   a . The hook  122   a  defines a pocket or reception area  123   a  configured to attach to and around a portion of the posterior arch of the C1 vertebra. The hook  122   a  may be configured to be bent at various angles to accommodate varying C1 vertebra anatomy. 
         [0056]    Again, as best seen in  FIG. 11 , the second arm  117   b  includes a slot or the like  119   b  that extends in and along the side of the second arm  117   b . A second adjustable element  120   b  is retained in the slot  119   b  so as to be translatable (movable) along the length of the slot  119   b  (in the medial-lateral direction or transverse plane) and rotatable relative thereto. As such, the second adjustable element  120   b  is rotatable relative to the second arm  117   b . A weld plate  140   b  ensures that a hook  121   b  of the second adjustable element  120   b  does not disassociate from the body  116 /arm  117   b . The weld plate  120   b  also ensures that the translation of the first adjustable element remains parallel with the medial-lateral (transverse) plane and does not travel obliquely. 
         [0057]    The second adjustable element  120   b  includes a generally U-shaped rod holder  121   b  defining a slot between two cupped sides, the slot configured to receive the rod ( 134   a ,  134   b ) of a C2 component ( 114   a ,  114   b ). While not seen, the two cupped sides have threading on the inside cupped surface thereof. The internal threading is configured to receive a threaded set screw  90  for securing the rod of a C2 component. 
         [0058]    The second adjustable element  120   b  also includes a hook  122   b  extending from the underside of the rod holder  121   b . The hook  122   b  defines a pocket or reception area  123   b  configured to attach to and around a portion of the posterior arch of the C1 vertebra. The hook  122   b  may be configured to be bent at various angles to accommodate varying C1 vertebra anatomy. 
         [0059]    The C2 component  114   a  will now be described. The second C2 component  114   b  is a mirror image of the first C2 component  114   a . As such the second C2 component  114   b  will not be discussed in detail since its features, components and configuration are the same as the first C2 component, and its numerical labeling of which ends in a “b”. The first C2 component  114   a  has a body  130   a  having a rod, shaft, pole or the like (rod)  134   a  that projects outwardly from an end of the body  130   a . The rod  134   a  is configured to be received in the rod holder  121   a  of the C1 component. The rod  134   a  also has a length that allows the rod holder  121   a  of the C1 component to receive and retain the rod  134   a  at various longitudinal positions along the rod, thereby providing length adjustment between the C1 component/C1 vertebra and the first C2 component/C2 vertebra. This accommodates variations in anatomy (i.e. spacing between the C1 vertebra and the C2 vertebra). 
         [0060]    The body  130   a  moreover has a rod holder  131   a  that is formed at an end of the body  130   a  opposite the rod  134   a . The rod holder  131   a  utilizes an end wall of the body  130   a  as one side of the two sided rod holder  131   a  and a shaped flange as the other side. The outside surface of the end wall and the inside surface of the shaped flange both have threading for receiving the threaded set screw  90 . A hook  132   a  extends from a bottom of the rod holder  131   a  and defines a hook area  133   a  (see, e.g.,  FIG. 12 ). The hook  131   a  is configured to attach onto and extend under a portion of the lamina of the C2 vertebra adjacent one side of its spinous process SP. This is in like manner to the first C2 component  14   a  shown in  FIGS. 8-10  wherein the first C2 component  14   a  is designed to hook or grasp onto and/or around the inferior end of the C2 lamina. 
         [0061]    As indicated above, the second C2 component  114   b  is a mirror configuration of the C1 component  114   a . Thus, while the first C2 component  114   a  is configured to connect to the left side of the C2 vertebra and extend to the left side of the C1 vertebra, the second C2 component  114   b  is configured to connect to the right side of the C2 vertebra and extend to the right side of the C1 vertebra. The rod  44   a  of the first C2 component  114   a  is received in the rod holder  24   a  of the C1 component  12  while the rod  44   b  of the second C2 component  114   b  is received in the rod holder  24   b  of the C1 component. 
         [0062]    The implant  100  is attached to the spine in a manner similar if not the same as the implant  10 . As such, reference should be made to  FIGS. 8-10  that show various views of the vertebral immobilization implant  10  situated, implanted on, or otherwise attached to and between the C1 vertebra and the C2 vertebra. The vertebral immobilization implant  100  stabilizes the C1 and C2 vertebrae relative to one another. 
         [0063]    While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only illustrative embodiments thereof have been show and described and that all changes and modifications that are within the scope of the following claims are desired to be protected. 
         [0064]    All references cited in this specification are incorporated herein by reference to the extent that they supplement, explain, provide a background for or teach methodology or techniques employed herein.