Abstract:
A spinal cage device for fusion of spinal vertebrae comprising a cage body having a cavity defined by upper, lower, and side walls; a piston selectively insertable into the cavity through a side wall, the piston having at least one angled surface; at least one channel extending through at least one of the upper wall and the lower wall; at least one fastening member moveable within the at least one channel between a first disengaged position and a second engaged position; and wherein in second engaged position the at least one fastening member is held substantially stationary relative to the cage body by contact with the piston. According to one aspect of the invention, the device includes a locking means for supplementing fixation of the piston to the cage body.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This continuation patent application claims the benefit of and incorporates herein by reference, U.S. patent application Ser. No. 13/022,305, filed Feb. 7, 2011; and U.S. Provisional Application Ser. No. 61/302,088, filed Feb. 6, 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a spinal cage device. More specifically, the present invention is a stand-alone spinal cage designed to obviate the need for an accompanying anterior spinal plating systems. 
         [0004]    2. Description of the Related Art 
         [0005]    Traditional spinal cages are often implanted with anterior plating to prevent movement of the spinal cage over time. The present invention is a stand-alone spinal cage that obviates the need to use anterior spinal plating systems. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    The present invention is a spinal cage device for fusion of spinal vertebrae comprising a cage having a cavity defined by upper, lower, and side walls; a piston selectively insertable into the cavity through a side wall, the piston having at least one angled surface; at least one channel extending through at least one of the upper wall and the lower wall; at least one fastening member moveable within the at least one channel between a first disengaged position and a second engaged position; and wherein in second engaged position the at least one fastening member is held substantially stationary relative to the cage by contact with the piston. According to one aspect of the invention, the device includes a locking means for supplementing fixation of the piston to the cage by the internal screw(s). According to another aspect of the invention, the fastening members (e.g., nails or pins) of the device are porous to allow bone growth therethrough. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an assembly view of a first embodiment of the invention. 
           [0008]      FIG. 2A  is a front view of the first embodiment. 
           [0009]      FIG. 2B  is side elevation through line  2 B- 2 B of  FIG. 2A . 
           [0010]      FIG. 2C  is a rear isometric view of the first embodiment. 
           [0011]      FIG. 3A-3C  depict various views of the piston of the first embodiment. 
           [0012]      FIG. 4A-4B  shows a fastening member and bushing of the first embodiment. 
           [0013]      FIG. 5A and 5B  are a rear isometric and a top elevation view, of the first embodiment. 
           [0014]      FIG. 6  is an assembly view of a second embodiment of the invention. 
           [0015]      FIG. 7A-7C  are a bottom, rear elevation, and top elevation of the cage of the second embodiment. 
           [0016]      FIG. 8A and 8B  are a front elevation and a side isometric view of the piston of the second embodiment. 
           [0017]      FIG. 9A and 9B  depict a fastening member and bushing, respectively, of the second embodiment. 
           [0018]      FIG. 10  is a rear isometric view of the second embodiment. 
           [0019]      FIG. 11A  is an assembly view of a third embodiment of the invention. 
           [0020]      FIG. 11B  is a rear isometric view of the third embodiment. 
           [0021]      FIG. 12A and 12B  are a front isometric and a front view of the cage of the third embodiment.  FIG. 12C  is a side elevational view of the third embodiment of Applicant&#39;s invention. 
           [0022]      FIG. 13A and 13B  are rear and front isometric views, respectively, of the piston, locking plate, and piston screw of the third embodiment. 
           [0023]      FIG. 13C  is a front isometric view of the piston of the third embodiment. 
           [0024]      FIG. 14A-14C  are various views of the fastening member of the third embodiment. 
           [0025]      FIG. 14D  is a bushing of the third embodiment. 
           [0026]      FIG. 15A-15C  are rear, front, and side elevations, respectively, of the third embodiment in the engaged state. 
           [0027]      FIG. 16A  is an assembly view of a fourth embodiment of the invention. 
           [0028]      FIG. 16B  is a rear isometric view of the fourth embodiment in an engaged state.  FIG. 16C  is a perspective view of a fourth embodiment of Applicant&#39;s device. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    The present invention may be used in the cervical, lumbar, or thoracic regions of the spine. Some components of the embodiment described herein, such as the cage bodies, are preferably made of biocompatible OXPEKK, a poly-ether-ketone-ketone sold under the registered trademark of Oxford Performance Materials, Inc., Enfeld, Conn., USA. Alternative embodiments contemplate fabrication from biocompatible PEEK (poly-ether-ether-ketone). OXPEKK has approximately one-and-a-half to two times the compressive strength of PEEK, and therefore may be suited for constructing the cage body. 
         [0030]    In addition to the foregoing, it should be noted that, while the embodiments described herein are solid bodies, they may also be formed as porous bodies, as described in U.S. application Ser. No. 612/952,788 (filed Nov. 23, 2010), entitled “Spinal Cage Device” and incorporated by reference herein. 
         [0031]    While the terms “upper,” “lower,” “front,” “rear,” and similar terms are used throughout this document, it should be expressly understood that such are simply terms of convenience only to aid in description of the invention, and the orientation of the invention disclosed herein after during implantation is primarily within the surgeon&#39;s discretion. 
       FIRST EMBODIMENT 
       [0032]    A first embodiment  18  of the invention is shown in  FIGS. 1-5 .  FIG. 1  is an assembly view of the first embodiment  18 , which comprises a cage body  20  having upper and lower walls  22 ,  24  with ridges  26 . Upper and lower walls  22 ,  24  partially define a cavity  28  of the cage body  20 . Openings  30  through the upper and lower walls  22 ,  24  provide access to the cavity  28  to allow for bone growth thereinto from adjacent vertebrae. A piston  32  having upper and lower angled surfaces  34 ,  36  is insertable into the cavity  28  through a piston opening in the posterior sidewall of the cage body  20  to engage and drive nails  56 . Piston screws  38  may thereafter be inserted through a piston faceplate  40  and secured to screw mounts  42  located in the cavity  28  near the posterior opening. 
         [0033]      FIGS. 2A-2C  show the cage body  20  is greater detail. Upper and lower rails  44 ,  46  extend along the length of, and protrude into the cavity  28  from, the upper and lower wails  22 ,  24 , respectively. Screw mounts  42  are located near the posterior side of the cavity  28 . Openings  30  through the upper wall  22  and lower wall  24  provide access the cavity  28  to allow for bone growth thereinto from adjacent vertebrae. Cylindrical channels  31  are located between the two openings  30  and provide a cylindrical path through the upper wall  22  to the cavity  28 . A pair of cylindrical channels (not shown) is disposed through the lower wall in similar fashion and aligned with the upper channels  31 . 
         [0034]      FIGS. 3A-3C  show the piston  32  of the first embodiment in greater detail. The piston  32  has upper and lower angled planar surfaces  34 ,  36  approximately sixty degrees apart. Upper and lower grooves  48 ,  50  are formed longitudinally along the piston  32  and extend between the faceplate  40  and the upper and lower angled planar surfaces  34 ,  36 . The grooves  48 ,  50  are alignable with, and during insertion guide the piston  32  along, upper and lower rails  44 ,  46  (see  FIG. 2A ), respectively, of the cage body  20 . Shoulders  52  are formed in the piston body having a thickness T1. Engagement surfaces  53  are located between the shoulders  52  and the angled surfaces  34 ,  36 . 
         [0035]      FIGS. 4A and 4B  show a titanium nail  56  and bushing  58  of the first embodiment in greater detail. The nail  56  is generally cylindrical and has a nail head  60  of thickness Ti at a proximal end and tapers to a point  62  at the distal end. The nail head  60  has an angled portion  64  corresponding to the angled surfaces  34 ,  36  of the piston  32  (see  FIGS. 3A-3C ). The upper end  66  of the bushing  58  corresponds in shape to the upper wall  22  (see  FIGS. 2A-2C ) such that, when assembled, the bushing  58  is flush with the ridges  26  of the upper surface of the cage body  20  (see, e.g.,  FIG. 5A ). 
         [0036]      FIG. 5A  and  FIG. 5B  are an isometric view and a top elevation view, respectively, of the first embodiment  18  with the nails  56  in a second engaged position. During implantation, the angled portions  60  of the nail heads  60  (see  FIGS. 4A-4B ) are contacted by and become flush with the angled surfaces  34 ,  36  of the piston  32  (see  FIGS. 3A-3C ), which, as the piston  32  is inserted further into the cavity  28 , causes the nails  56  to move upwardly through the channels  31 . In this manner, engagement of the upper angled surface  34  with the nail head  60  causes movement of the piston  32  into the cavity  28  to drive the nail  56  into the adjacent vertebra above the embodiment  18 . Similarly, engagement of the lower angled surface  36  with nail heads causes movement of the piston  32  into the cavity  28  to drive lower nails (not shown) into the adjacent vertebra below the embodiment. 
         [0037]    After complete insertion of the piston  32 , each nail head  60  becomes flush with the corresponding engagement surface  53  to prevent the nail  56  from receding back into the cavity  28 . This ensures fastening of the nail  56  to adjacent bone matter. The upper and lower rails  44 ,  46  (see  FIGS. 2A ,  2 C) occupy the upper and lower grooves  48 ,  50 , respectively, to ensure proper alignment of the piston  32  within the cavity  28 . The ridged bushings  58  are fitted within the channels  31  in the annular space between the nail  56  and channel walls to facilitate slidable movement of the nail  56  therein. By threading the screws  38  through the faceplate  40  and the screw mounts  42 , the piston  32  is drawn into the cavity  28  and secured to the cage body  20 . 
       SECOND EMBODIMENT 
       [0038]    A second embodiment  118  of the invention, shown in  FIG. 6-10 , comprises a cage body  120  having upper and lower walls  122 ,  124  with ridges  126 . Upper and lower walls  122 ,  124  partially define a cavity  128  of the cage body  120 . Openings  130  through the upper and lower walls  122 ,  124  provide access to the cavity  128  to allow for bone growth thereinto from adjacent vertebrae. A piston  132  having upper and lower angled planar surfaces  134 ,  136  is insertable into the cavity  128  through a piston opening in the posterior wall of the cage body  120 . Screws  138  may thereafter be inserted through a piston faceplate  140  and secured to screw mounts  142  located in the cavity  128  proximal to the piston opening. 
         [0039]      FIG. 7A-7C  show the cage body  120  of the second embodiment is greater detail.  FIG. 7A and 7C  are bottom and top elevations, respectively, of the cage body  120 .  FIG. 7B  is a rear elevation of the cage body  120 . Upper and lower rails  144 ,  146  extend along the length of, and protrude into the cavity  128  from, the upper and lower walls  122 ,  124 , respectively. Screw mounts  142  are located near the rear side of the cavity  128 . Openings  130  through the upper and lower walls  122 ,  144  provide access to the cavity  128  to allow for bone growth thereinto from adjacent vertebrae. As shown in  FIG. 7A , a channel  131  is located between the two openings  130  and provides a path through the lower wall  124  to the cavity. As shown in  FIG. 7B , two channels  133  are located between the two openings  130  and provide a path through the upper wall  122  to the cavity  128 . 
         [0040]      FIG. 8A and 8B  show the piston  132  of the second embodiment  118  in greater detail. The piston  132  has upper and lower angled surfaces  134 ,  136  angled approximately sixty degrees apart. Upper and lower grooves  148 ,  150  are formed longitudinally along the piston  132  from the faceplate  140  to the upper and lower angled surfaces  134 ,  136 . Upper and lower grooves  148 ,  150  are alignable with, and during insertion guide the piston  132  along, upper and lower rails  144 ,  146  (see  FIG. 7B ) of the cage body  120 . Shoulders  152  are formed in the piston body having a thickness T2. Engagement surfaces  153  are located between the shoulders  152  and the angled surfaces  134 ,  136 . 
         [0041]      FIGS. 9A and 9B  show a titanium pin  156  and bushing  158 , respectively, of the second embodiment  118  in greater detail. Each pin  156  has an angled engagement surface  160  that corresponds to the angle of the upper and lower angled surfaces  134 ,  136  of the piston  132  (see  FIG. 8B ). Each pin  156  tapers to a wedge  162  at the distal end. The upper end  166  of the bushing  158  corresponds in shape to the upper wall  122  (see  FIGS. 7A-7C ) such that, when assembled, the bushing  158  is flush with the ridges  126  of the upper surface of the cage body  120  (see, e.g.,  FIG. 10 ). 
         [0042]      FIG. 10  is a perspective view of the second embodiment  118  with the pins  156  in an engaged position. During implantation, the angled engagement surfaces  160  (see  FIGS. 9A-9B ) of the pins  156  are contacted by and become flush with the upper and lower angled surfaces  134 ,  136  of the piston  132 , which, as the piston  132  is inserted further into the cavity  128 , causes the pins  156  to move through the channels  131 ,  133  to an engaged position. In this manner, engagement of the upper and lower angled surfaces  134 ,  136  with the pins  156  causes movement of the piston  132  into the cavity  128  to drive the pins  156  into the adjacent vertebra. The piston screw heads are positioned anterior of the posterior surface of the faceplate  140 . 
         [0043]    After insertion of the piston  132  is complete, each engagement surface  160  is flush with the engagement surfaces  153  of the piston to prevent the pins  156  from receding back into the cavity  128  and ensuring fastening of the pins  156  with adjacent bone matter. The upper and lower rails  144 ,  146  (see  FIGS. 7B ) occupy the upper and lower grooves  148 ,  150 , respectively, of the piston  132  to ensure proper alignment of the piston  132  within the cavity  128 . The ridged bushings  158  are fitted within the upper and lower channels  131 ,  133  in the annular space between the pin  156  and channel wails to facilitate movement between disengaged and engaged positions. 
       THIRD EMBODIMENT 
       [0044]    A third embodiment  218  of the invention, shown in  FIG. 11-15 , comprises a cage body  220  having upper and lower walls  222 ,  224  with ridges  226 . Upper and lower walls  222 ,  224  partially define a cavity  228 . Openings  230  through the upper and lower wall  222 ,  224  and sidewalls provide access to the cavity  228  to allow for bone growth thereinto from adjacent vertebrae. Upper and lower lock openings  225 ,  227  are formed through the upper and lower walls,  222 ,  224 , respectively proximal to a piston opening in the posterior wall of the cage body  220 . 
         [0045]    A piston  232  having upper and lower angled surfaces  234 ,  236  is insertable into the cavity  228  through the piston opening. A screw  238  may thereafter be inserted through a piston faceplate  240  and secured to a screw mount  242  located at the posterior of the cavity  228 . A locking plate  280  having a closed end  283  and an opened end  284  defined by upper and lower fingers  286 ,  288  is rotatably attached to the faceplate  240  with a locking member screw  282 . 
         [0046]      FIG. 12A-12C  show the cage body  220  in greater detail. A screw mount  242  is located near the front of the cavity  228 . Openings  230  through the upper wall  222  provide access to the cavity  228  to allow for bone growth thereinto from adjacent vertebrae. Rectangular channels  231 ,  233  are located between the openings  230  and provide paths through the upper wall  222  and lower wall  224  to the cavity. As shown in  FIG. 12C , upper and lower rails  244 ,  246  extend along the length of, and protrude into the cavity  228  from, the upper and lower walls  222 ,  224 , respectively. 
         [0047]      FIG. 13A-13C  show the piston  232 , piston screw  238 , and locking plate  280  of the third embodiment in greater detail. The piston  232  has upper and lower angled surfaces  234 ,  236  angled approximately sixty degrees apart. Upper and lower grooves  248 ,  250  are formed longitudinally along the piston  232  between the faceplate  240  and the upper and lower angled surfaces  234 ,  236 . Upper and lower grooves  248 ,  250  are alignable with, and during insertion guide the piston  232  along, upper and lower rails  244 ,  246  (see  FIG. 12C ) of the cage body  220 . Shoulders  252  are formed in the piston body having a thickness T3. Engagement surfaces  253  are located between the shoulders  252  and the upper and lower angled surfaces  234 ,  236 . 
         [0048]      FIGS. 14A-14D  show a titanium pin  256  and bushing  258 , respectively, of the third embodiment  218  in greater detail. Each pin  256  has an angled engagement surface  260  that corresponds to the angle of the upper and lower angled surfaces  234 ,  236  of the piston  132  (see  FIG. 13C ). Each pin  256  tapers to an angled wedge  262  at the distal end. The upper end  266  of the bushing  258  corresponds in shape to the ridged upper surface (see  FIG. 7A-7C ) such that, when assembled, the bushing  258  is flush with the ridges  226  of the cage body  220  (see, e.g.,  FIG. 10 ). 
         [0049]      FIGS. 15A-15C  disclose rear, front, and side elevations, respectively of the third embodiment  218 . During implantation, the angled engagement surfaces  260  (see  FIGS. 14A-14C ) are contacted by and become flush with the upper and lower angled surfaces  234 ,  236  of the piston  232 , which, as the piston  232  is inserted further into the cavity  228 , causes the pins  256  to move upwardly through the channels  231 ,  233  to an engaged position. In this manner, engagement of the upper and lower angled surfaces  234 ,  236  with the pin  256  causes movement of the piston  232  into the cavity  228  to drive the pins  256  into the adjacent vertebra. 
         [0050]    After insertion of the piston  232  is complete, each engagement surface  260  becomes flush with the engagement surface  253  to prevent the nail from receding back into the cavity  228  and ensuring fastening of the nail  256  with adjacent bone matter. The upper and lower rails  244 ,  246  (see  FIGS. 12A ,  12 C) occupy the upper and lower grooves  248 ,  250 , respectively, to ensure proper alignment of the piston  232  within the cavity  228 . The ridged bushings  258  are fitted within the channels  231 ,  233  in the annular space between the titanium pin  256  and channel walls to facilitate movement and retain the pins  256  in the channels  231 ,  233 . 
         [0051]    Operation of the locking plate for this embodiment is identical to operation of the locking mechanism described hereafter with reference to the fourth embodiment 
       FOURTH EMBODIMENT 
       [0052]    A fourth embodiment comprises a cage body  320 , shown in  FIGS. 16A-16C , comprises upper and lower walls  322 ,  324  with ridges  326 . Upper and lower walls  322 ,  324  partially define a cavity  328 . Openings  330  through the upper wall  322  provide access to the cavity  328  to allow for bone growth thereinto from adjacent vertebrae. Upper and lower lock openings  325 ,  327  are formed in the upper and lower walls  322 ,  324 , respectively near the piston opening  328 . 
         [0053]    A piston  332  having upper and lower angled surfaces  334 ,  336  is insertable into the cavity  328 . A screw  338  may thereafter be inserted through a piston faceplate  340  and secured to a screw mount located in the cavity  328 . A locking plate  380  having a closed end  383  opened end  384  defined by upper and lower fingers  386 ,  388  is rotatably attached to the faceplate  340  with a screw  382 . As shown in  FIG. 16B , the fastening members of the fourth embodiment  318  comprises porous blades  356  with lateral passages  357  therethrough to allow bone growth. 
         [0054]      FIG. 16B  and  FIG. 16C , which both depict the piston in an engaged position within the cage body  320 , show the locking plate  380  in the unlocked and locked position, respectively. In the unlocked position, the screw  338  may be passed between the upper and lower fingers  386 ,  388 , with the screw head accessible. Once the piston  382  is engaged with the cage body  320  to support the blades  356 , the locking plate  380  is rotated around the locking plate screw  381  so that the lower finger  386  extends into the lower lock opening  325  and upper finger  386  covers the head of the piston screw  382 . In this position, the locking plate  380  prevents “back out” of the piston screw  382  and piston  332 , which assures engagement of the blades  356  with the adjacent vertebrae. 
         [0055]    Although the embodiments of the present invention disclose titanium fastening members, alternative embodiments include stainless steel fastening members. 
         [0056]    For each of the above-described embodiments, the upper and lower walls are at least substantially parallel. In alternative embodiments, however, the upper and lower walls may be angled relative to one another to correspond to curvature of the spine (e.g., to correspond to a lordotic curvature) at the targeted region of implantation. In such case, the front and rear sides will be of differing heights. 
         [0057]    In addition to the nail and/or pins described hereinabove, alternative embodiments of the present invention contemplate a fastening member with a blade- or knifelike appearance, such as the porous blades shown in  FIG. 17  and  FIG. 20 . 
         [0058]    The present invention is described in terms of preferred illustrative embodiments of specifically described stand-alone spinal cages. Those skilled in the art will recognize that yet other alternative embodiments of such a device can be used in carrying out the present invention. Other aspects, features, and advantages of the present invention may be obtained from a study of this disclosure and the drawings, along with the appended claims.