Abstract:
A spinal fusion device that is expandable. The device features a top and bottom surface for engaging adjacent vertebrae, a hollow center for stacking of bone or bone growth material, and a slidable mechanism with grooves for expanding or unexpanding the device.

Description:
PRIORITY CLAIM 
       [0001]    This application based upon and claims the priority date U.S. Provisional Patent Application 62/041,911 entitled “Spinal Implant Device” filed Aug. 26, 2014, the contents of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the invention relate to the field of orthopedic surgery, and more particularly, to implants to be placed between vertebrae in the spine. 
       BACKGROUND 
       [0003]    Spinal stabilization is one approach to alleviating chronic back pain caused by disabled disk material or excessive movement of individual vertebrae. Conventional stabilization techniques include fusing two or more vertebrae together to circumvent or immobilize the area of excessive movement. Normally, the vertebral disk material which separates the vertebrae is removed and bone graft material is inserted in the space for interbody fusion. In addition to, or in place of, the bone graft material, a spinal implant may be inserted in the intervertebral space. 
         [0004]    The conventional surgical approach for stabilization has been posteriorly for ease of access to the spine and to avoid interfering with internal organs and tissues. Usually the implant site is prepared to maintain natural lordosis and to accept a certain sized implant within certain pressure limits. This requires considerable time and skill by the surgeon. 
       DESCRIPTION OF THE PRIOR ART 
       [0005]    U.S. Pat. No. 8,556,979, issued Oct. 15, 2013, describes an expandable fusion device capable of being installed inside an intervertebral disc space to maintain normal disc spacing and restore spinal stability. The fusion device includes a body portion, a first end plate, and a second endplate; both of these endplates can be moved in a direction away from the body portion or towards the body portion into an unexpanded configuration. 
       SUMMARY OF THE INVENTION 
       [0006]    Embodiments of the invention are directed to an expandable spinal fusion device comprising upper and lower sections with depending sidewalls forming a cube-like or rectangular structure with a hollow center. The upper and lower sections comprise a top and a bottom surface, respectively, for engaging adjacent vertebrae, a slidable mechanism for expanding or compacting the device, and a hollow center allowing for packing with bone graft or similar bone growth inducing material. The slidable mechanism comprises slots or grooves on each of the sidewalls depending from the top and bottom surfaces, and a distractor. The distractor comprises a rod, and a body. An actuator enables distraction. The rod can be telescopic or a jack screw type rod. The distractor comprises a body with wedge-shaped sidewalls and grooves for engaging the depending sidewalls of the upper and lower section. When the distractor is actuated, the body slides upwards, downwards or sideways depending on the groove geometry. 
         [0007]    The device is inserted between the adjacent vertebrae and expanded or increased in height to engage the opposing surfaces of the adjacent vertebra. The adjacent vertebrae are forced apart as the height of the implant increases. The spinal fusion device may be used unilaterally or bilaterally. 
         [0008]    Accordingly, it is an objective of the instant invention to teach a posterior surgical approach for placement of an adjustable spinal implant for interbody fusion, allowing the implant to be inserted through a small incision and increased in size in situ. 
         [0009]    It is another objective of the instant invention to teach a spinal implant which allows the surgeon to provide for lordosis intraoperatively and to distract through the implant. 
         [0010]    It is yet another objective of the instant invention to teach an implant facilitating interbody fusion through bone graft or an ingrowth type implant. 
         [0011]    Although embodiments are directed to posterior surgical approaches and to provide for lordosis intraoperatively, it is to be understood that the invention may be employed in cervical and thoracic spinal procedures as well as from any direction, that is, anterior, posterior and lateral. 
         [0012]    Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1A  is a perspective view of an embodiment of a spinal implant. 
           [0014]      FIG. 1B  is a side view of the implant in a non-expanded position. 
           [0015]      FIG. 2A  is a perspective view showing the implant in an expanded position. 
           [0016]      FIG. 2B  is a side view of the implant in an expanded position. 
           [0017]      FIG. 3  is a perspective view showing the various parts of the assembly. 
           [0018]      FIG. 4  is a side view of a depending side wall. 
           [0019]      FIG. 5  is a perspective view of the top surface. 
           [0020]      FIG. 6  is a perspective view of the top surface as viewed from an angle. 
           [0021]      FIG. 7  is a top view of the proximal planar end of the distractor. 
           [0022]      FIG. 8  is a side view of the wedge-shaped side wall of the proximal and distal planar end plates. 
           [0023]      FIG. 9A  is a perspective view of the proximal planar end plate. 
           [0024]      FIG. 9B  is a side view of the proximal planar end plate. 
           [0025]      FIG. 10  is a perspective view of the planar end plate. 
           [0026]      FIG. 11  is a side view of a distractor body disposed within the hollow interior of the implant. 
           [0027]      FIG. 12  is a perspective view of the distractor body. 
           [0028]      FIG. 13  is a top view of the distal planar end plate of the distractor. 
           [0029]      FIG. 14  is a side view of the distal planar end plate of the distractor. 
           [0030]      FIG. 15  is a frontal view of the distal planar end plate. 
           [0031]      FIG. 16  is a perspective view of the distal planar end plate. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application or uses. 
         [0033]    It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the invention. One having ordinary skill in the relevant art, however, will readily recognize that the invention can be practiced without one or more of the specific details or with other methods. The present invention is not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the present invention. 
         [0034]    Embodiments of the invention may be practiced without the theoretical aspects presented. Moreover, the theoretical aspects are presented with the understanding that Applicants do not seek to be bound by the theory presented. 
         [0035]    Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0036]    As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, to the extent that the terms “including”, “includes”, “having”, “has”, “with”, or variants thereof are used in either the detailed description and/or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” 
       Expandable Spinal Fusion Device(s) 
       [0037]    A spinal fusion is typically employed to eliminate pain caused by the motion of degenerated disk material. Upon successful fusion, a fusion device becomes permanently fixed within the intervertebral disc space. 
         [0038]    Referring now to the Figures, the spinal fusion device  200  is inserted into the intervertebral space in the insertion mode to replace damaged, missing or excised disk material. In general embodiments, the spinal fusion device  200  comprises an upper section  202 , a lower section  204 , a hollow body  201  and a distractor  213 . The device may be made of conventional materials used for surgical implants, such as stainless steel and its many different alloys, titanium, titanium alloys, metallic alloys, polymeric materials, plastics, plastic composites, ceramic and any other metal or material with the requisite strength and biologically inert properties. 
         [0039]    The spinal fusion device  200  ( FIGS. 1A ,  1 B,  2 A) for implanting or placing between adjacent vertebrae comprises a hollow body  201  having an upper section  202  with a top surface  203  for contacting one vertebra and a lower section  204  having a bottom surface  205  for contacting an adjacent vertebra, said top surface and said bottom surface providing a means for engaging the vertebra, the upper section having opposing depending sidewall  206  and sidewall  207 , each sidewall having opposing angled sides  208 ,  251  for slidably receiving a wedge-shaped distractor  213 , a planar end  210  whereby the planar end  212  of the top sidewall engages the planar end  211  of the bottom side wall; and, a distractor  213 . 
         [0040]    Turning to  FIG. 3 , the distractor  213  is defined by a proximal end  214  and a distal planar end wall  302 , the proximal end  214  and distal  302  planar end walls connected to opposing wedge-shaped side walls, wherein the wedge-shaped side walls slidably engage a groove  216  in the sidewall  206  of the upper section  202  and the sidewall  207  of the bottom section  204 , whereby the distance between the top  203  and bottom surfaces  205  is adjustable as the wedge-shaped sidewalls of the distractor body slidably move relative to each other. 
         [0041]    The opposing wedge-shaped side walls of the distractor increase distance between the upper section  202  and lower section  204  when the wedge-shaped side walls of the distractor are closest in linear distance (y) to each other. The wedge-shaped side-walls  209  of the distractor slidably move in the groove  216  of the depending side walls  206 ,  207  as the jack screw  218  is threaded into the distractor body  213 . 
         [0042]    In some embodiments, an actuator comprises a bore  217  and a jack screw  218 , the jack screw  218  into a planar body  219  placed within the hollow body comprising an aperture  220  and cylindrical body  221  for receiving the jack screw  218 , the planar body  219  dimensioned for insertion into the groove  222  of the inwardly facing surface  223  of the depending sidewalls. 
         [0043]    The hollow body  201  of the device is formed by the upper section sidewalls  206 , the lower section side walls  207 , the proximal end  214  and distal planar end plates  215  of the distractor, the hollow body dimensioned to fit bone or bone graft material. 
         [0044]    In some embodiments, the upper and/or lower sidewalls  206 ,  207  further comprise opposing grooves etched on the inward facing surfaces  223  of the upper and/or lower section side walls for receiving the planar body  219  inserted into the hollow body. 
         [0045]    In other embodiments, a spinal fusion device for adjusting the space between vertebrae comprises a hollow body, an upper section  202  having a top surface  203  for contacting a vertebra, the top surface  203  partitioned by at least one cross-sectional bar  224  thereby forming a rectangular or a square shaped aperture, a lower section  204  having a bottom surface  205  for contacting an adjacent vertebra, the upper  202  and lower  204  sections comprising opposing depending sidewalls  206 ,  207 , each sidewall being dimensioned for engaging a distractor and having a groove  216  for slidably engaging the distractor, the distractor comprising a proximal end  214  and a distal end  215 . 
         [0046]    In some embodiments, the depending side walls  206 ,  207  comprise at least one pair of opposing grooves  222  on each inwardly facing inner surface  223 , the groove being formed by a lip  227  protruding inwards from the vertical section  228  of the depending sidewalls for receiving the proximal  214  and distal ends  215  of the distractor. 
         [0047]    In other embodiments, the opposing depending side walls  206 ,  207  of the upper  202  and lower sections  204  comprise vertical planar sides  228  which angle  229  inwards, for receiving a wedge-shaped distractor body, and a planar distal edge  212  for contacting the opposing sidewall. 
         [0048]    The distractor comprises a proximal end  214 , a distal end  215 , and a body  219  disposed in the hollow body of the device, a jack screw  218  for adjusting the distractor, whereby the distance between the top  203  and bottom  205  surfaces is adjustable by moving the upper section  202  relative to the lower section  204 , the upper and lower section depending side walls  206 ,  207  comprising grooves for slidably engaging wedge-shaped spacers of the distractor body and slidably moving the top and bottom surfaces. 
         [0049]    The distractor further comprises a bore  217 , a planar body  219  placed within the hollow body comprising an aperture  220  and cylindrical body  221  for receiving the jack screw  218 , the planar body  219  dimensioned for insertion into the groove  222  of the inwardly facing surfaces  223  of the depending sidewalls. The wedge-shaped sides of the distractor slidably move in the groove  216  of the angled edges  230  of the depending side walls  206 ,  207  as the jack screw  218  is threaded into the distractor body. 
         [0050]    The proximal end  214  of the distractor comprises the bore  217  for receiving the jack screw  218  and the distal end  215  a plate  231  which protrudes into the hollow body and comprises an aperture  232 , aligned with the aperture  220  in the planar body  219  and bore  217  of the proximal end  214  of the distractor. The proximal  214  and distal  215  ends of the distractor comprise wedge-shaped sides  209  which slidably engage the upper and lower section depending side walls  206 ,  207 . 
         [0051]    In some embodiments, the proximal  214  and distal  215  ends of the top  203  and bottom surface  205  comprise an interlocking groove  216  for receiving the proximal and distal ends  214 ,  215  of the distractor. 
         [0052]    In some embodiments, the hollow body is formed from the depending sidewalls  206 ,  207  of the upper and lower sections  202 ,  204  and proximal and distal ends  214 ,  215  of the distractor. 
         [0053]    In other embodiments, the upper and lower sections  202 ,  204  further comprise a means for engaging a vertebra, the engaging means comprising a bracket  224  ( FIG. 3 ). In embodiments, the hollow body is dimensioned to fit bone or bone graft material. 
         [0054]    Turning to  FIGS. 7-16 , various components of the distractor are shown in more detail.  FIG. 7  shows a top view of the distractor  213 . The proximal end  213  comprises interface grooves  300   a ,  300   b  run parallel to each other on opposing sides of the outer planar end plate  301  of the proximal end distractor body  214 . The outer planar end plate  301  is connected to the inner planar end plate  302  and is of a smaller width, height and surface area than the inner planar end plate  302  of the proximal end of the distractor. The wedge-shaped sides of the device comprises a lead-in taper section  303 . The wedge-shaped sides  209  are connected to the lead-in taper  303 . 
         [0055]    The distal end  215  of the hollow body  201  comprises a similar tapered lead-in  404  and wedge-shaped side architecture as the proximal end  405 . However, the wedge-shaped sides are connected to a lock-up stop  400  which protrudes into the hollow body. The lock-up stop  400  further comprises an aperture  402  for receiving the jack screw  218 , the aperture comprising a lock-up screw thread  403 . Similar to the distractor  213  the hollow body  201  includes interface grooves  406   a  along a first side edge  410  and interface grooves  406   b  along the opposite side edge  411 . 
         [0056]    The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of this disclosure, may make modifications and improvements within the spirit and scope of the invention. The following non-limiting examples are illustrative of the invention. 
         [0057]    All documents mentioned herein are incorporated herein by reference. All publications and patent documents cited in this application are incorporated by reference for all purposes to the same extent as if each individual publication or patent document were so individually denoted. By their citation of various references in this document, Applicants do not admit any particular reference is “prior art” to their invention.