Abstract:
A spine plate defines a body having a posterior surface or side and an anterior surface or side. The body also has a pair of bone screw bores for each vertebra to which the spine plate will be attached. The bone screw bores extend between the posterior side and the anterior side. A relief area is provided between each pair of bone screw bores in the anterior surface of the body. The relief area opens to both bone screw bores to allow displacement of the bone screw when entering the respective bone screw bore. The relief area also opens to both bone screw bores to permit an instrument to be received therein to remove a bone screw from one of the bone screw bores.

Description:
RELATED APPLICATIONS 
     This patent application claims the benefit of and/or priority to U.S. Provisional Patent Application No. 60/903,499 filed Feb. 26, 2007, entitled “Spine Plates, Bone Screws and Spine Plate Constructs” the entire contents of which is specifically incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to devices for the internal fixation of the spine particularly within the fields of orthopedics and/or neurosurgery such as spinal implants for holding vertebral bones fixed relative to one another and, more particularly, to static bone fixation implants for use in spinal surgical procedures for stabilizing the relative motion of, temporarily or permanently immobilizing, bones of the spine. 
     2. Background Information 
     Spine plates have been used for more than 20 years to increase spine stability following single and multi-level spine surgery. Plates implanted during surgery for reasons such as disease, trauma, defect, accident or the like, are used to stabilize one or more spinal vertebrae. Stabilization leads to a proper healing or a desired outcome. The plate is mounted to one or more vertebrae during the surgery. Typically, bone screws are used to mount the plate to the one or more vertebrae. It is important during the mounting process that the plate be properly aligned on the vertebrae for receipt of the mounting screws. 
     In some instances, it is desirous to cause the fusion of two adjacent vertebrae. If this is the case, the surgeon makes an incision to reach the spine. Tissues and muscles are retracted (spread apart) to reveal the proper level in the spine. The cartilaginous material or disc between the two vertebrae is removed and the bone surface abraded to encourage a bleeding surface. Blood from the bleeding surfaces is desired in order for the bones to fuse. The space between the adjacent vertebrae is filled with bone graft. A plate is then screwed into the superior (top) and inferior (bottom) vertebrae. This stabilizes the spine to facilitate fusion and healing. 
     In all cases, the spine plates must be fastened to the vertebrae. This is accomplished by bone screws. The bone screws are received in bores of the spine plate and hold the spine plate to the vertebra. In order to prevent anti-rotation or “backing out” of the bone screw once it has been rotated into the bone (vertebra), caps or prong structures are placed into drive sockets in the heads of the bone screws. This detrimentally adds an extra component to the plate assembly or construct. It would be desirable to provide a spine plate and/or spine plate assembly that eliminates this extra component. 
     Moreover, bone screw bores of current spine plates do not have the configuration or geometry to allow angulation of bone screws as appropriate or to prohibit angulation of bone screws as appropriate while providing a positive retention of the bone screw by the plate alone. It would be desirable to provide a spine plate and/or spine plate assembly having bone screw bores that are configured to provide for angulation of a bone screw and/or the prohibition of angulation of a bone screw as appropriate while providing a positive retention of the bone screw by the plate alone. 
     Other objects will become apparent from the following. 
     SUMMARY OF THE INVENTION 
     A single to multi-level spine plate having a pair of bone screw bores for each vertebra includes a relief area that is provided between the bone screw bores of each pair of bone screw bores. The relief area opens to both bone screw bores of the bone screw bore pair to allow displacement of a bone screw when entering the respective bone screw bore. The relief area also permits an instrument to be received therein to remove a bone screw from one of the bone screw bores if necessary. 
     In one form, the spine plate defines a body having a posterior surface or side and an anterior surface or side. The body also has a pair of bone screw bores for each vertebra to which the spine plate will be attached. The bone screw bores extend between the posterior side and the anterior side. A relief area, channel or groove is provided between each pair of bone screw bores in the anterior surface of the body. The relief area opens to both bone screw bores to allow displacement of the bone screw when entering the respective bone screw bore. The relief area also opens to both bone screw bores to permit an instrument to be received therein to remove a bone screw from one of the bone screw bores. 
     The relief area preferably, but not necessarily, narrows between the pair of bone screw bores. In one form, the relief area is formed in an hour-glass shape. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more 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: 
         FIG. 1  is an anterior perspective view of an exemplary embodiment of a two level (2-L) spine plate fashioned in accordance with the present principles; 
         FIG. 2  is another anterior perspective view of the 2-L spine plate of  FIG. 1 ; 
         FIG. 3  is a posterior plan view of the 2-L spine plate of  FIG. 1 ; 
         FIG. 4  is a side view of the 2-L spine plate of  FIG. 3  taken along line  4 - 4  thereof; 
         FIG. 5  is an anterior plan view of the 2-L spine plate of  FIG. 1 ; 
         FIG. 6  is a sectional view of the 2-L spine plate of  FIG. 5  taken along line  6 - 6  thereof; 
         FIG. 7  is a sectional view of the 2-L spine plate of  FIG. 5  taken along line  7 - 7  thereof; 
         FIG. 8  is a sectional view of the 2-L spine plate of  FIG. 5  taken along line  8 - 8  thereof; 
         FIG. 9  is an enlarged portion of the sectional view of  FIG. 8  taken along circle  9 - 9  thereof; 
         FIG. 10  is an enlarged portion of the sectional view of  FIG. 7  taken along circle  10 - 10  thereof; 
         FIG. 11  Is an enlarged portion of the sectional view of  FIG. 7  taken along circle  11 - 11  thereof; 
         FIG. 12  is an enlarged portion of the sectional view of  FIG. 6  taken along circle  12 - 12  thereof; 
         FIG. 13  is a side view of an exemplary fixed angle bone screw fashioned in accordance with the present principles; 
         FIG. 14  is an end view of the fixed angle bone screw of  FIG. 13  taken along line  14 - 14  thereof; 
         FIG. 15  is an enlarged portion of the fixed angle bone screw of  FIG. 13  taken along circle  15 - 15  thereof; 
         FIG. 16  is a side view of an exemplary variable angle bone screw fashioned in accordance with the present principles; 
         FIG. 17  is an end view of the variable angle bone screw of  FIG. 16  taken along line  17 - 17  thereof; 
         FIG. 18  is an enlarged portion of the variable angle bone screw of  FIG. 16  taken along circle  18 - 18  thereof; 
         FIG. 19  is a side view of an emergency (variable) bone screw fashioned in accordance with the present principles; 
         FIG. 20  is an end view of the emergency bone screw of  FIG. 19  taken along line  20 - 20  thereof; 
         FIG. 21  is an enlarged portion of the emergency bone screw of  FIG. 19  taken along circle  21 - 21  thereof; 
         FIG. 22  is a sectional view of the 2-L spine plate with various ones of the present bone screws situated therein of  FIG. 23  taken along line  22 - 22  thereof; 
         FIG. 23  is a sectional view of the present 2-L spine plate with various ones of the present bone screws of  FIG. 22  taken along line  23 - 23  thereof; 
         FIG. 24  is a posterior plan view of the present 2-L spine plate with various ones of the present bone screws of  FIG. 22 ; 
         FIG. 25  is a sectional view of the present 2-L spine plate with various ones of the present bone screws of  FIG. 24  taken along line  25 - 25  thereof; 
         FIG. 26  is an enlarged portion of the sectional view of  FIG. 25  taken along circle  26 - 26  thereof; 
         FIG. 27  is an enlarged portion of the sectional view of  FIG. 22  taken along circle  27 - 27  thereof; 
         FIG. 28  is an enlarged portion of the sectional view of  FIG. 22  taken along circle  28 - 28  thereof; and 
         FIG. 29  is an enlarged portion of the sectional view of  FIG. 23  taken along circle  29 - 29  thereof. 
     
    
    
     Like reference numerals indicate the same or similar parts throughout the several figures. 
     A description of the features, functions and/or configuration of the components depicted in the various figures will now be presented. It should be appreciated that not all of the features of the components of the figures are necessarily described. Some of these non discussed features as well as discussed features are inherent from the figures. Other non discussed features may be inherent in component geometry and/or configuration. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the figures and particularly to  FIGS. 1-12 , there is depicted an embodiment of a two-level (2-L) spine or spinal plate generally designated  10  fashioned in accordance with the present principles. Single level and multiple level (up to five levels) spine plates are also contemplated that utilize the present principles. It should be understood that the 2-L spine plate  10  is representative of all such plates. These plates are adapted and/or configured to be placed onto vertebrae of the spine. The 2-L spine plate  10  is formed of a suitable biocompatible material such as titanium, stainless steel, alloys thereof, and other biomaterials. 
     The 2-L spine plate  10  is defined by a body  12  having an anterior side  13  and a posterior side  15 . The body  12  is formed of a middle section  14 , a first neck  16  extending from one side of the middle section  14  and terminating in a first end  18  distal the middle section  14 , and a second neck  20  extending from another side of the middle section  14  and terminating in a second end  22  distal the middle section  14 . It should be appreciated that the terms first and second are arbitrary unless indicated otherwise. As best discerned in FIGS.  4  and  6 - 9 , the plate body  12  is curved or arched from end  18  to end  22  (along a saggittal plane). The plate body  12  may be made in various sizes. 
     The first neck  16  has a first opening or window  28  formed between the middle section  14  and the first end  18  and is preferably oval as shown, but may be other shapes as desired. The first opening  28  forms a graft window of and for the plate  10  and defines first and second neck portions  24  and  26  of the first neck  16 . The first neck portion  24  of the first neck  16  extends from one side of a first side boss  56  of the middle section  14  to a first end boss  30  of the first end  18 . The second neck portion  26  of the first neck  16  extends from one side of a second side boss  58  of the middle section  14  to a second end boss  32  of the first end  18 . The second neck  20  has a second opening or window  44  formed between the middle section  14  and the second end  22  and is preferably oval as shown, but may be other shapes as desired. The second opening  44  forms a graft window of and for the plate  10  and defines first and second neck portions  40  and  42  of the second neck  20 . The first neck portion  40  of the second neck  20  extends from another side of the first side boss  56  of the middle section  14  to a first end boss  46  of the second end  22 . The second neck portion  42  of the second neck  20  extends from another side of the second side boss  58  of the middle section  14  to a second end boss  48  of the second end  22 . 
     The middle section  14  has a first bone screw bore  60  formed in the side boss  56 . The first bone screw bore  60  is configured to accommodate a bone screw such as described and/or shown herein. Moreover, as best seen in  FIGS. 7 and 11 , the first bone screw bore  60  is configured as a cylindrical hole having an arcuate lip  72  formed around a majority of the annular rim of the bore  60 . The lip  72  forms an undercut  74  for the bone screw to “snap” into in order to retain the bone screw into the bore  60  when so implanted (see, e.g.  FIG. 10 ). The bore  60  has sidewalls that are spherical and configured to provide a ten degree (10°) angulation range in the medial-lateral direction for a bone screw (see, e.g.  FIGS. 25 and 26 ). 
     A second bone screw bore  62  is formed in the side boss  58  of the middle section  14 . The second screw bore  62  is configured to accommodate a bone screw such as described and/or shown herein. The second bone screw bore  62  is configured as a cylindrical hole having an arcuate lip  84  formed around a majority of the annular rim of the bore  62 . The lip  84  forms an undercut in like manner to undercut  74  of bore  60 , for the bone screw to “snap” into in order to retain the bone screw into the bore  62  when so implanted. The bore  62  has sidewalls that are spherical and configured to provide a ten degree (10°) angulation range in the medial-lateral direction for a bone screw (see, e.g.  FIGS. 25 and 26 ). As can be discerned in  FIGS. 24 ,  25  and  26 , the bone screw bore  60  provides angulation in a medial direction (inwards) from a longitudinal axis of the bone screw therein, while the bone screw bore  62  provides angulation in a medial direction (inwards) from a longitudinal axis of the bone screw therein. 
     A relief area, trough, channel or the like  64  is provided in the anterior side  13  of the plate body  12  between the first and second bores  60  and  62  of the middle section  14 . The relief area  64  is preferably, but not necessarily, hour-glass shaped (see, e.g.  FIG. 5 ) having ends that open into or provide communication with the respective first and second bores  60  and  62 . As detailed in  FIG. 12  with respect to the bone screw bore  52  wherein the relief area thereof is labeled  54 , the relief area is configured to allow the bone screw to displace within the screw pockets when entering the bore. The relief area also is used to remove the bone screw by placing an instrument in the hole of the relief area and splaying open the screw holes. 
     The first end  18  has a first bone screw bore  34  formed in the first boss  32 . The first bone screw bore  34  is configured to accommodate a bone screw such as described and/or shown herein. Moreover, as best seen in  FIGS. 7 and 10 , the first bone screw bore  34  is configured as a cylindrical hole having an arcuate lip  68  formed around a majority of the annular rim of the bore  34 . The lip  68  forms an undercut  70  for the bone screw to “snap” into in order to retain the bone screw into the bore  34  when so implanted. The bore  34  has sidewalls that are spherical and configured to provide bone screw angulation. The bore  34  is configured to provide a thirty degree (30°) angulation range in the cephalad-caudal direction for a bone screw (see, e.g.  FIGS. 22 and 24 ). 
     The first end  18  also has a second bone screw bore  36  formed in the second boss  34 . The second bone screw bore  36  is configured to accommodate a bone screw such as described and/or shown herein. The second first bone screw bore  36  is configured as a cylindrical hole having an arcuate lip  80  formed around a majority of the annular rim of the bore  36 . The lip  80  forms an undercut, in like manner to undercut  70  of bore  34 , for the bone screw to “snap” into in order to retain the bone screw into the bore  36  when so implanted. The bore  36  has sidewalls that are spherical and configured to provide bone screw angulation. The bore  34  is configured to provide a thirty degree (30°) angulation range in the cephalad-caudal direction for a bone screw (see, e.g.  FIGS. 22 and 24 ). As can be discerned in  FIGS. 24 ,  25  and  26 , the bone screw bore  34  provides angulation in a medial direction (inwards) from a longitudinal axis of the bone screw therein, while the bone screw bore  36  provides angulation in a medial direction (inwards) from a longitudinal axis of the bone screw therein. 
     A relief area, trough, channel or the like  38  is provided in the anterior side  13  of the plate body  12  between the first and second bores  34  and  36  of the first end  18 . The relief area  38  is preferably, but not necessarily, hour-glass shaped (see, e.g.  FIG. 5 ) having ends that open into or provide communication with the respective first and second bores  34  and  36 . As detailed in  FIG. 12  with respect to the bone screw bore  52  wherein the relief area thereof is labeled  54 , the relief area is configured to allow the bone screw to displace within the screw pockets when entering the bore. The relief area also is used to remove the bone screw by placing an instrument in the hole of the relief area and splaying open the screw holes. 
     The second end  22  of the body  12  of the spine plate  10  has a first bone screw bore  50  formed in the first boss  46  of the second end plate  22 . The first bone screw bore  50  is configured to accommodate a bone screw such as described and/or shown herein. Moreover, the first bone screw bore  50  is configured as a cylindrical hole having an arcuate lip  88  formed around a majority of the annular rim of the bore  50 . The lip  88  forms an undercut, in like manner to undercut  70  of bore  34 , for the bone screw to “snap” into in order to retain the bone screw into the bore  50  when so implanted. Again, in like manner to the bore  34  but configured opposite thereto, the bore  50  has sidewalls that are spherical and configured to provide bone screw angulation. The bore  50  is configured to provide a thirty degree (30°) angulation range in the cephalad-caudal direction for a bone screw but opposite for those of the first end  18  (see, e.g.  FIGS. 22 and 24 ). 
     The second end  22  of the body  12  of the spine plate  10  has a second bone screw bore  52  formed in the second boss  34  of the second end plate  22 . The second bone screw bore  52  is configured to accommodate a bone screw such as described and/or shown herein. Moreover, the second first bone screw bore  52  is configured as a cylindrical hole having an arcuate lip  76  formed around a majority of the annular rim of the bore  52 . The lip  76  forms an undercut  78  (see  FIGS. 7 and 12 ) for the bone screw to “snap” into in order to retain the bone screw into the bore  52  when so implanted. The bore  52  has sidewalls that are spherical and configured to provide bone screw angulation. The bore  52  is configured to provide a thirty degree (30°) angulation range in the cephalad-caudal direction for a bone screw but opposite to that of the first end  18  (see, e.g.  FIGS. 22 and 24 ). 
     A relief area, trough, channel or the like  54  is provided in the anterior side  13  of the plate body  12  between the first and second bores  50  and  52  of the second end  22  (see, e.g.  FIG. 12 ). The relief area  54  is preferably, but not necessarily, hour-glass shaped having ends that open into or provide communication with the respective first and second bores  50  and  52 . As detailed in  FIG. 12 , the relief area is configured to allow the bone screw to displace within the screw pockets when entering the bore. The relief area also is used to remove the bone screw by placing an instrument in the hole of the relief area and splaying open the screw holes. 
     The bone screw bores or screw pockets (as defined by their geometry and/or configuration) may have a fixed or pre-disposed angulation rather than provide for a variable angulation as hereinbefore described. This would allow positioning of a received bone screw at the fixed or pre-disposed angle. This may be particularly true for the cephelad-caudel screw pockets. 
     Referring now to  FIGS. 13-15 , there is depicted an exemplary embodiment of a fixed angle bone screw, generally designated  100 , that may be used with the present plate  10 . The fixed angle bone screw  100  is characterized by a body  102  fashioned from a suitable biocompatible material such as titanium, stainless steel, alloys thereof, and the like. The body  102  has a shank  104  extending from a head  106 . The shank  104  is in the form of an auger having a tip  112  and helical threads on the outer periphery thereof. The head  106  extends from the end of the shank  104  distal the tip  112 . The head  106  includes an upper annular tapered area  108  that terminates in a socket  110 . The socket  110  is provided on the longitudinal axis of the bone screw  100  and particularly the shank  104  and may be in the form of a hexalobe, or similar, drive or otherwise. The periphery of the head  106  is essentially annular. 
     Referring to  FIG. 15 , the fixed angle screw head  106  includes a peripheral lip  114  that cooperates with a lip and undercut of a bone screw bore of the plate  10  as described herein in order to provide a snap feature between the bone screw bore configuration of the plate and the bone screw. Thus, as the bone screw  100  is received into a bone screw bore of the plate the peripheral lip  114  of the bone screw  100  axially passes the lip of the bone screw bore (see, e.g.  FIG. 27 ) to snap into place in the undercut. Axial to the peripheral lip  114  is a transition area  115  that axially tapers from and helps define the peripheral lip  114  to an angulation area  116 . The angulation area  116  of the fixed angle bone screw acts within the bone screw bore to prevent angulation once received therein. As particularly shown in  FIG. 27 , the larger diameter of the angulation area  116  prevents angulation of the bone screw in the bone screw bore (screw pocket) as the angulation area  116  meets the spherical walls of the screw pocket. Thus, once the boring angle of the fixed angle bone screw  100  is set, the angulation area  116  prevents further angulation through interaction with the geometry of the screw pocket. A second transition area  118  axially extends from the angulation area  116  to a shaft head  120 . The fixed angle screw  100  may be used in any one of the bone screw bores of the plate  10 . 
     Referring now to  FIGS. 16-18 , there is depicted an exemplary embodiment of a variable angle bone screw, generally designated  130 , that may be used with the present plate  10 . The variable angle bone screw  130  is characterized by a body  132  fashioned from a suitable biocompatible material such as titanium, stainless steel, alloys thereof, and the like. The body  132  has a shank  134  extending from a head  136 . The shank  134  is in the form of an auger having a tip  142  and helical threads on the outer periphery thereof. The head  136  extends from the end of the shank  134  distal the tip  142 . The head  136  includes an upper annular tapered area  138  that terminates in a socket  140 . The socket  140  is provided on the longitudinal axis of the bone screw  130  and particularly the shank  134  and may be in the form of a hexalobe drive or otherwise. The periphery of the head  136  is essentially annular. 
     Referring to  FIG. 18 , the variable angle screw head  136  includes a peripheral lip  144  that cooperates with a lip and undercut of a bone screw bore of the plate  10  as described herein in order to provide a snap feature between the bone screw bore configuration of the plate and the bone screw. Thus, as the bone screw  130  is received into a bone screw bore of the plate the peripheral lip  144  of the bone screw  130  axially passes the lip of the bone screw bore (see, e.g.  FIG. 28 ) to snap into place in the undercut. Axial to the peripheral lip  144  is a transition area  145  that axially tapers from and helps define the peripheral lip  144  to an angulation area  146 . The angulation area  146  of the variable angle bone screw acts within the bone screw bore to allow angulation once received therein. As particularly shown in  FIG. 28 , the smaller or reduced diameter of the angulation area  146  allows angulation of the bone screw in the bone screw bore (screw pocket) as the angulation area  146  meets the spherical walls of the screw pocket. Thus, once the boring angle of the variable angle bone screw  130  is set, the angulation area  146  allows further angulation via the geometry of the screw pocket. A second transition area  148  axially extends from the angulation area  146  to a shaft head  150 . The variable angle screw  130  may be used in any one of the bone screw bores of the plate  10 . Such variable angle screws  130  are shown in the bone screw bores  60  and  62  of the middle section  14  (see, e.g.  FIGS. 22 ,  25  and  26 ). 
     Referring now to  FIGS. 19-21 , there is depicted an exemplary embodiment of an emergency (variable) bone screw, generally designated  160 , that may be used with the present plate  10 . The emergency bone screw  160  is characterized by a body  162  fashioned from a suitable biocompatible material such as titanium, stainless steel, alloys thereof, and the like. The body  162  has a shank  164  extending from a head  166 . The shank  164  is in the form of an auger having a tip  172  and helical threads on the outer periphery thereof. The head  166  extends from the end of the shank  164  distal the tip  172 . The head  166  includes an upper annular tapered area  168  that terminates in a socket  170 . The socket  170  is provided on the longitudinal axis of the bone screw  160  and particularly the shank  164  and may be in the form of a hexalobe drive or otherwise. The periphery of the head  166  is essentially annular. 
     Referring to  FIG. 21 , the emergency screw head  166  includes a peripheral lip  174  that cooperates with a lip and undercut of a bone screw bore of the plate  10  as described herein in order to provide a snap feature between the bone screw bore configuration of the plate and the bone screw. Thus, as the bone screw  160  is received into a bone screw bore of the plate the peripheral lip  174  of the bone screw  160  axially passes the lip of the bone screw bore, such as previously described, to snap into place in the undercut. Axial to the peripheral lip  174  is an elongated transition area  175  that axially tapers from and helps define the peripheral lip  174  to an angulation area  176 . The angulation area  176  of the emergency bone screw  160  acts within the bone screw bore to allow angulation once received therein. This is similar to that shown in  FIG. 28  as described above with respect to variable angle bone screw  130 . A second transition area  178  radially outwardly tapers from the angulation area  176  to an oversized shaft head  180 . The emergency screw  160  may be used in any one of the bone screw bores of the plate  10 . The helical threads of the emergency bone screw  160  are slightly larger in diameter than fixed or variable screws. 
     Reference is now made to  FIGS. 23 and 29 . When bone screws are installed in the bone screw bores of the middle section  14 , the axis of the bone screws are at a centroid of the screw pocket. 
     It should be appreciated that a single level (1-L) spine plate has first and second ends each having first and second bone screw bores and a single neck section. A two level (2-L) spine plate has a middle section having first and second bone screw bores, first and second necks extending from each side of the middle section and each having an elongated window, a first end at the first neck distal the middle section and having first and second bone screw bores, and a second end at the second neck distal the middle section and having first and second bone screw bores. A three level (3-L) spine plate has two middle sections connected by a middle neck, then a neck and end section like the 2-L spine plate on an end of the two middle sections. This continues for higher level spine plates. 
     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 preferred 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.