Patent Publication Number: US-2015081026-A1

Title: Spinal Spacer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Patent Application No. 60/846,568 to Murillo et al., filed Sep. 22, 2006, and entitled “Spinal Spacer”, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to systems, methods, and devices applicable to spinal surgery. More specifically, the present invention is directed to a spinal spacer for use by medical personnel (i.e., doctor) in spinal and other surgical procedures. In some embodiments of the present invention relates to a spinal spacer for insertion into a disk space defined between two adjacent vertebrae, in order to restore an appropriate height between the vertebrae and to allow bone fusion to take place between said adjacent vertebrae. 
     2. Background of the Invention 
     Vertebrae are the individual irregular bones that make up the spinal column (aka ischis)—a flexuous and flexible column. There are normally thirty-three vertebrae in humans, including the five that are fused to form the sacrum (the others are separated by intervertebral discs) and the four coccygeal bones which form the tailbone. The upper three regions comprise the remaining 24, and are grouped under the names cervical (7 vertebrae), thoracic (12 vertebrae) and lumbar (5 vertebrae), according to the regions they occupy. This number is sometimes increased by an additional vertebra in one region, or it may be diminished in one region, the deficiency often being supplied by an additional vertebra in another. The number of cervical vertebrae is, however, very rarely increased or diminished. 
     A typical vertebra consists of two essential parts: an anterior (front) segment, which is the vertebral body; and a posterior part—the vertebral (neural) arch—which encloses the vertebral foramen. The vertebral arch is formed by a pair of pedicles and a pair of laminae, and supports seven processes, four articular, two transverse, and one spinous, the latter also being known as the neural spine. 
     When the vertebrae are articulated with each other, the bodies form a strong pillar for the support of the head and trunk, and the vertebral foramina constitute a canal for the protection of the medulla spinalis (spinal cord), while between every pair of vertebrae are two apertures, the intervertebral foramina, one on either side, for the transmission of the spinal nerves and vessels. 
     Conventional spinal spacer assemblies are use in spinal fusion procedures to repair damaged or incorrectly articulating vertebrae. Spinal fusion employs the use of spacer assemblies having a hollow mesh spacer tube and end caps that space apart and fuse together adjacent vertebrae. These mesh spacer tubes are often formed of titanium and are available in varying shapes and sizes. In addition, they can be trimmed on site by the surgeon to provide a better individual fit for each patient. Conventional spinal spacer assemblies come in different cross sections. These spacer assemblies are generally hollow and include openings in the side thereof to provide access for bone to grow and fuse within the mesh tube. 
     There exists a need for further improvements in the field of spinal spacer assemblies of the present type. 
     SUMMARY OF THE INVENTION 
     In some embodiments, the present invention relates to a spinal spacer. The spinal spacer having a wall configured to enclose a hollow interior, wherein the wall is further configured to have a top portion and a bottom portion. The top and bottom portions are configured to include a plurality of protrusions or teeth configured to protrude away from the top and bottom portions. The wall is further configured to have at least one curved portion (or curvature) and include a plurality of grooves and an opening. 
     In some embodiments, the present invention relates to a spinal spacer assembly. The assembly includes a spinal spacer. The spinal spacer has a wall having two sides, a front portion, and a back portion, wherein the front and back portions are configured to be disposed between the two sides. The front and back portions are configured to include at least one curved portion. At least one side of the two sides includes at least one groove and at least one opening. The two sides and the front and back portions are configured to enclose a hollow interior. The wall is further configured to have a top surface and a bottom surface. The top and bottom surfaces are configured to include a plurality of protrusions configured to protrude away from the top and bottom portions. In some embodiments, the wall may have a variable thickness. 
     Further features and advantages of the invention, as well as structure and operation of various embodiments of the invention, are disclosed in detail below with references to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. 
         FIG. 1A  is a perspective view of an exemplary spinal spacer, according to some embodiments of the present invention. 
         FIG. 1B  is a bottom view of the exemplary spinal spacer shown in  FIG. 1A . 
         FIG. 1C  is a top view of the exemplary spinal spacer shown in  FIG. 1A . 
         FIG. 1D  is a side view of the exemplary spinal spacer shown in  FIG. 1A . 
         FIG. 1E  is a cross-sectional view of the exemplary spinal spacer shown in  FIG. 1A . 
         FIG. 1F  is another side view of the exemplary spinal spacer shown in  FIG. 1A . 
         FIG. 1G  is another top view of the exemplary spinal spacer shown in  FIG. 1A . 
         FIG. 1H  is yet another side view along with a cross-section view of the exemplary spinal spacer shown in  FIG. 1A . 
         FIG. 2A  is a perspective view of another exemplary spinal spacer, according to some embodiments of the present invention. 
         FIG. 2B  is a bottom view of the exemplary spinal spacer shown in  FIG. 2A . 
         FIG. 2C  is a top view of the exemplary spinal spacer shown in  FIG. 2A . 
         FIG. 2D  is a side view of the exemplary spinal spacer shown in  FIG. 2A . 
         FIG. 2E  is a cross-sectional view of the exemplary spinal spacer shown in  FIG. 2A . 
         FIG. 2F  is another side view of the exemplary spinal spacer shown in  FIG. 2A . 
         FIG. 2G  is another top view of the exemplary spinal spacer shown in  FIG. 2A . 
         FIG. 2H  is yet another side view along with a cross-section view of the exemplary spinal spacer shown in  FIG. 2A . 
         FIG. 3A  is a perspective view of another exemplary spinal spacer, according to some embodiments of the present invention. 
         FIG. 3B  is a side view of the exemplary spinal spacer shown in  FIG. 3A . 
         FIG. 3C  is a top view and a cross-sectional view of the exemplary spinal spacer shown in  FIG. 3A . 
         FIG. 3D  is a side view and a cross-sectional view of the exemplary spinal spacer shown in  FIG. 3A . 
         FIG. 3E  is another side view of the exemplary spinal spacer shown in  FIG. 3A . 
         FIG. 3F  is another top view of the exemplary spinal spacer shown in  FIG. 3A . 
         FIG. 3G  is another top view of the exemplary spinal spacer shown in  FIG. 3A . 
         FIG. 4A  is a perspective view of another exemplary spinal spacer, according to some embodiments of the present invention. 
         FIG. 4B  is a side view of the exemplary spinal spacer shown in  FIG. 4A . 
         FIG. 4C  is a top view and a cross-sectional view of the exemplary spinal spacer shown in  FIG. 4A . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An exemplary embodiment of the spinal spacer, according to the present invention is illustrated in  FIGS. 1A-1H . Another exemplary embodiment of the spinal spacer is illustrated in  FIGS. 2A-2H . As can be understood by one skilled in the art, these embodiments are shown for illustrative purposes and are not intended to limit the scope of the invention. 
       FIGS. 1A-1H  illustrate a spinal spacer  100  that includes a top portion  102 , a bottom portion  104 , a front side  106 , a back side  108 , a left side  110 , and a right side  112 . The front side  106 , the back side  108 , the left side  110  and the right side  112  may have a varying height, length, thickness, and/or curvature radius, as illustrated in  FIGS. 1A-1H . As further illustrated in  FIGS. 1A-1H , the sides  106 ,  108 ,  110 , and  112  are configured to include at least one curved portion that can be configured to have a variable degree curvature radius. 
     As shown in  FIG. 1A , a combination of the sides  106 ,  108 ,  110 , and  112  forms a wall that encloses a hollow interior  122 . The top portion  102  and the bottom portion  104  include a plurality of protrusions or teeth  118  (hereinafter, referred to as “teeth”). Teeth  118  can be configured to be spaced throughout the top portion  102  and the bottom portion  104 . As can be understood by one skilled, the teeth  118  can be configured to have variable thickness, height, and width as well as angles of orientation with respect to surfaces of portions  102  and  104 . The teeth  118  can be further configured to provide additional support after the spinal spacer  100  is implanted in the vertebrae of the patient. The teeth  118  can reduce movement of the spinal spacer  100  in the vertebrae and create additional friction between the vertebrae and the spacer  100 . If more than one spinal spacer  100  is implanted in the vertebrae of the patient, the teeth  118  of one spinal spacer  100  can be configured to interact and/or mate with teeth of another spinal spacer, thereby creating stacked spacers. Such interaction can be useful, when multiple spinal spacers are needed to be implanted into the vertebrae. As shown in  FIG. 1H  (detail B of the side view of the spinal spacer  100 ), the teeth  118  can be configured to have a shape of triangular protrusions extending away from the surfaces of the top and bottom portions of the spinal spacer  100 . The triangular protrusions can be configured to be right-angled isosceles triangles, as illustrated in detail B of  FIG. 1H . As can be understood by one skilled in the art, the triangular protrusions can be any size and shape triangles are not necessarily limited to the right-angled isosceles triangles. Further, the triangular protrusions can be configured to protrude a distance D 12  away from the surface (whether top or bottom surfaces) of the spinal spacer  100 . The triangular protrusions can also be spaced apart a distance D 11 , as illustrated in detail B of  FIG. 1H . In some embodiments, D 12 =0.03 millimeters (“mm”) and D 11 =0.1 mm. As can be understood by one skilled in the art, the teeth  118  can be configured to have any shape, size, or orientation as well as can protrude any distance away from the surfaces of the spinal spacer and can have any distance between them. 
     Referring back to  FIGS. 1A-C , in some embodiments, the teeth  118  can be configured to be evenly spaced on the top portion  102  and the bottom portion  104 . In other embodiments, the teeth  118  can be configured to be spaced in a predetermined order, such as the one shown in  FIGS. 1A-C . 
       FIG. 1B  is a bottom view of the spinal spacer  100  shown in  FIG. 1A . The teeth  118  are configured to be disposed on the bottom portion  104  in a predetermined order. Specifically, the teeth  118  include a plurality of spacings  135 ( a, b ) and  133 ( a, b ). As illustrated in  FIG. 1B , spacings  133   a  and  135   a  are configured to be disposed between teeth  118  on the bottom face  104  adjacent the front portion  106  of the spinal spacer  100 . The spacings  133   b  and  135   b  are configured to be disposed between teeth  118  on the bottom face  104  adjacent the back portion  108  of the spinal spacer  100 . Each spacing  133  and  135  is configured to be disposed at predetermined angles with regard to each other. In particular, spacings  133   a  and  133   b  are configured to be disposed at angles substantially matching a curvature of the front and back portions  106  and  108  of the spinal spacer  100 . Similarly, spacings  135   a  and  135   b  are also configured to be disposed at angles substantially matching a curvature of the portions  106 ,  108 . Further, the angular directions of spacings  133 ( a, b ) and spacings  135 ( a, b ) are configured to point away from each other, as illustrated in  FIG. 1B . Such disposition allows the spinal spacer to more closely match the shapes and sizes of the vertebrae and accommodate other spinal spacers  100  in the event that spinal spacers are stacked together. 
     As further illustrated in  FIG. 1B , some teeth  118  can have a different length than the other teeth  118 . For example, teeth located on the bottom surface  104  adjacent the right side  112  and the left side  110  can be configured to be longer than the teeth located on the bottom surface  104  adjacent the front and back portions  106 ,  108 . 
       FIG. 1C  is a top view of the exemplary spinal spacer  100  shown in  FIG. 1A . The top surface  102  also includes a plurality of teeth  118  that can be configured to have a similar structure as shown in  FIG. 1H . The teeth  118  can be disposed through the top surface  102  in a similar fashion as their counterparts in the bottom surface  104 . The teeth disposition can be substantially symmetrical about a center axis of the spacer  100 . As can be understood by one skilled in the art, such symmetrical disposition can be in the top surface  102  as well as in the bottom surface  104  of the spinal spacer  100 . Further, as shown in  FIGS. 1B and 1C , the wall formed adjacent to the right side  112  of the spinal spacer  100  can be configured to have a greater thickness than the walls formed adjacent to the front portion, back portion, and left side of the spacer  100 . In some embodiments, the thicknesses of the front portion, back portion, and left side can be configured to be substantially the same. As illustrated in  FIG. 1E , such thicknesses W 1  can be on the order of 0.1 mm, whereas thickness W 2  of the wall adjacent to the right side  112  can be on order of 0.19 mm. As can be understood by one skilled in the art, these numerical values are provided here for exemplary purposes only and are not intended to limit the present invention in any way. The front portion  106  and the back portion  108  can be further configured to have a convex/concave shape. The convexity/concavity of these portions can be further defined by a radius R 1 . In exemplary embodiments, R 1 =25°. The spacings  133  and  135  can be disposed between teeth  118  to substantially match such angular disposition. At least a portion of the teeth  118  can also be disposed along top and bottom surfaces in an angular direction that substantially matches radius R 1 . As can be understood by one skilled in the art, other radii can be used to define curvatures of the spinal spacer  100 . 
       FIG. 1D  is a side view of the exemplary spinal spacer  100  illustrated in  FIG. 1A . As illustrated in  FIG. 1D , the left side  110  of the spinal spacer  100  can be configured to have a lesser thickness M than the thickness N of the right side  112  of the spinal spacer  100 . The right side  112  can be further configured to accommodate an opening  116 . In some embodiments, the spacer  100  can be configured to include more than one opening  116 . As illustrated in  FIG. 1F , the spinal spacer  100  includes two openings  116 . The opening  116  can be configured to be for placing and maneuvering of the spacer  100  into the vertebrae of the patient. In some embodiments, the opening  116  can be configured to allow placement of the bone graft material. Further, the opening  116  can protrude through the wall of the right side  112  in such a way that it connects the hollow interior  122  with the exterior of the spacer  100 . In other embodiments, the opening  116  can be configured to be a groove, which means that the opening  116  does not protrude all the way from the exterior of the spacer  100  to the hollow interior  122 . In embodiments having more than one opening  116 , the openings can be configured to be symmetrically disposed on the right side  112 . As can be understood by one skilled in the art, the openings  116  can be disposed on any side of the spacer  100 . Additionally, as illustrated in  FIG. 1E , the right side  112  can also include a threaded opening  126  that includes threads  120  configured to accommodate bone screws for further securing of the spacer  100  in the vertebrae of the patient. In  FIG. 1E  embodiments, the openings  116  are placed symmetrically about the threaded opening  126 . 
     As shown in  FIGS. 1D and 1F , the openings  116  can have a length D 6  and width D 5  and can be disposed a distance D 7  away from the center of the threaded opening  126 . Opening  126  can have a radius R 5 . In exemplary embodiments, D 5 =0.5 mm, D 6 =0.15 mm, D 7 =0.09 mm, R 5 =0.5 mm. 
     The sides  106  and  108  may have varying degrees convexity and concavity, as illustrated in  FIGS. 1B ,  1 C,  1 D, and  1 G. Referring to  FIG. 1G , the front portion  106  has a curvature radius R 8 . The back portion  108  has a curvature radius  107 . The length of the spacer  100  can be defined as the distance D from the outermost point on the left side  110  to the outermost point on the right side  112 . The width of the spacer  100  can be defined as the distance E from the outermost point in the front side  106  to the outermost point on the backside  108 . In exemplary embodiments, R 7 =25 mm, R 8 =15 mm, D=22 mm, E=10.92 mm. The various curvatures of the spinal spacer  100  can be configured to closely match the shape of the vertebrae discs of the patient. This way, the spinal spacer allows better movement and flexibility of the vertebrae with the spacer installed. As can be understood by one skilled in the art, the sides  108  and  110  may have varying heights. For example, the height of side  108  can be greater than the height of side  110 , as illustrated in  FIG. 1B . Further, in some embodiments, the height of sides  106 ,  108 ,  110 , and  112  can vary throughout the device, as desired. For example, the height of at least a portion of the side  106  can be greater than the height of at least a portion of the side  108 . The height can also vary within each side  106 ,  108 ,  110 , and  112 . This means that, for example, a portion of the left side  110  can have a lesser height than another portion of the left side  110 . Such variation in heights throughout the sides of the spinal spacer  100  can be based on a particular design choice and further configured to accommodate various dimensions of the vertebrae of the patient. Also, the thickness of the walls can vary between the sides  106 ,  108 ,  110 , and  112 . The thickness can also vary within each side  106 ,  108 ,  110 , and  112 . This means that, for example, the thickness of at least a portion of the right side  112  can greater than the thickness of at least another portion of the right side  112 . 
     The openings  116  and  126  can be located anywhere in the sides of the spacer  100 . The openings  126  may include threads  120  or any other securing patterns (mechanical locks, hooks, etc.) configured to allow insertion of screws or other devices that secure the spinal spacer  100 . 
       FIGS. 2A-2H  illustrate an alternate embodiment of the spinal spacer  200 . The spinal spacer  200  is similar to the spinal spacer  100 . In the illustrated embodiment, the height of side  210  of the spinal spacer  200  is less than the height of side  110  of spacer  100 . In other aspects the two embodiments may be similar. 
       FIGS. 2A-2H  illustrate a spinal spacer  200  that includes a top portion  202 , a bottom portion  204 , a front side  206 , a back side  208 , a left side  210 , and a right side  212 . The front side  206 , the back side  208 , the left side  210  and the right side  212  may have a varying height, length, thickness, and/or curvature radius, as illustrated in  FIGS. 2A-2H . 
     As shown in  FIG. 2A , a combination of the sides  206 ,  208 ,  210 , and  212  forms a wall that encloses a hollow interior  222 . The top portion  202  and the bottom portion  204  include a plurality of teeth  218 . Teeth  218  can be configured to be spaced throughout the top portion  202  and the bottom portion  204 . As can be understood by one skilled, the teeth  218  can be configured to have variable thickness, height, and width as well as angles of orientation with respect to surfaces of portions  202  and  204 . The teeth  218  can be further configured to provide additional support after the spinal spacer  200  is implanted in the vertebrae of the patient. The teeth  218  can reduce movement of the spinal spacer  200  in the vertebrae and create additional friction between the vertebrae and the spacer  200 . If more than one spinal spacer  200  is implanted in the vertebrae of the patient, the teeth  218  of one spinal spacer  200  can be configured to interact and/or mate with teeth of another spinal spacer, thereby creating stacked spacers. Such interaction can be useful, when multiple spinal spacers are needed to be implanted into the vertebrae. As shown in  FIG. 2H  (detail B of the side view of the spinal spacer  200 ), the teeth  218  can be configured to have a shape of triangular protrusions extending away from the surfaces of the top and bottom portions of the spinal spacer  200 . The triangular protrusions can be configured to be right-angled isosceles triangles, as illustrated in detail B of  FIG. 2H . As can be understood by one skilled in the art, the triangular protrusions can be any size and shape triangles are not necessarily limited to the right-angled isosceles triangles. Further, the triangular protrusions can be configured to protrude a distance D 12  away from the surface (whether top or bottom surfaces) of the spinal spacer  200 . The triangular protrusions can also be spaced apart a distance D 11 , as illustrated in detail B of  FIG. 2H . In some embodiments, D 12 =0.03 millimeters (“mm”) and D 11 =0.1 mm. As can be understood by one skilled in the art, the teeth  218  can be configured to have any shape, size, or orientation as well as can protrude any distance away from the surfaces of the spinal spacer and can have any distance between them. 
     Referring back to  FIGS. 2A-2C , in some embodiments, the teeth  218  can be configured to be evenly spaced on the top portion  202  and the bottom portion  204 . In other embodiments, the teeth  218  can be configured to be spaced in a predetermined order, such as the one shown in  FIGS. 2A-C . 
       FIG. 2B  is a bottom view of the spinal spacer  200  shown in  FIG. 2A . The teeth  218  are configured to be disposed on the bottom portion  204  in a predetermined order. Specifically, the teeth  218  include a plurality of spacings  235 ( a, b ) and  233 ( a, b ). As illustrated in  FIG. 2B , spacings  233   a  and  235   a  are configured to be disposed between teeth  218  on the bottom face  204  adjacent the front portion  206  of the spinal spacer  200 . The spacings  233   b  and  235   b  are configured to be disposed between teeth  218  on the bottom face  204  adjacent the back portion  208  of the spinal spacer  200 . Each spacing  233  and  235  is configured to be disposed at predetermined angles with regard to each other. In particular, spacings  233   a  and  233   b  are configured to be disposed at angles substantially matching a curvature of the front and back portions  206  and  208  of the spinal spacer  200 . Similarly, spacings  235   a  and  235   b  are also configured to be disposed at angles substantially matching a curvature of the portions  206 ,  208 . Further, the angular directions of spacings  233 ( a, b ) and spacings  235 ( a, b ) are configured to point away from each other, as illustrated in  FIG. 2B . Such disposition allows the spinal spacer to more closely match the shapes and sizes of the vertebrae and accommodate other spinal spacers  200  in the event that spinal spacers are stacked together. 
     As further illustrated in  FIG. 2B , some teeth  218  can have a different length than the other teeth  218 . For example, teeth located on the bottom surface  204  adjacent the right side  212  and the left side  210  can be configured to be longer than the teeth located on the bottom surface  204  adjacent the front and back portions  206 ,  208 . 
       FIG. 2C  is a top view of the exemplary spinal spacer  200  shown in  FIG. 2A . The top surface  202  also includes a plurality of teeth  218  that can be configured to have a similar structure as shown in  FIG. 2H . The teeth  218  can be disposed through the top surface  202  in a similar fashion as their counterparts in the bottom surface  204 . The teeth disposition can be substantially symmetrical about a center axis of the spacer  200 . As can be understood by one skilled in the art, such symmetrical disposition can be in the top surface  202  as well as in the bottom surface  204  of the spinal spacer  200 . Further, as shown in  FIGS. 2B and 2C , the wall formed adjacent to the right side  212  of the spinal spacer  200  can be configured to have a greater thickness than the walls formed adjacent to the front portion, back portion, and left side of the spacer  200 . In some embodiments, the thicknesses of the front portion, back portion, and left side can be configured to be substantially the same. As illustrated in  FIG. 2E , such thicknesses W 1  can be on the order of 0.1 mm, whereas thickness W 2  of the wall adjacent to the right side  212  can be on order of 0.19 mm. As can be understood by one skilled in the art, these numerical values are provided here for exemplary purposes only and are not intended to limit the present invention in any way. The front portion  206  and the back portion  208  can be further configured to have a convex/concave shape. The convexity/concavity of these portions can be further defined by a radius R 1 . In exemplary embodiments, R 1 =25°. The spacings  233  and  235  can be disposed between teeth  218  to substantially match such angular disposition. At least a portion of the teeth  218  can also be disposed along top and bottom surfaces in an angular direction that substantially matches radius R 1 . As can be understood by one skilled in the art, other radii can be used to define curvatures of the spinal spacer  200 . 
       FIG. 2D  is a side view of the exemplary spinal spacer  200  illustrated in  FIG. 2A . As illustrated in  FIG. 2D , the left side  210  of the spinal spacer  200  can be configured to have a lesser thickness M than the thickness N of the right side  212  of the spinal spacer  200 . The right side  212  can be further configured to accommodate an opening  216 . In some embodiments, the spacer  200  can be configured to include more than one opening  216 . As illustrated in  FIG. 2F , the spinal spacer  200  includes two openings  216 . The opening  216  can be configured to be for placing and maneuvering of the spacer  200  into the vertebrae of the patient. In some embodiments, the opening  216  can be configured to allow placement of the bone graft material. Further, the opening  216  can protrude through the wall of the right side  212  in such a way that it connects the hollow interior  222  with the exterior of the spacer  200 . In other embodiments, the opening  216  can be configured to be a groove, which means that the opening  216  does not protrude all the way from the exterior of the spacer  200  to the hollow interior  222 . In embodiments having more than one opening  216 , the openings can be configured to be symmetrically disposed on the right side  212 . As can be understood by one skilled in the art, the openings  216  can be disposed on any side of the spacer  200 . Additionally, as illustrated in  FIG. 2E , the right side  212  can also include a threaded opening  226  that includes threads  220  configured to accommodate bone screws for further securing of the spacer  200  in the vertebrae of the patient. In  FIG. 2E  embodiments, the openings  216  are placed symmetrically about the threaded opening  226 . 
     As shown in  FIGS. 2D and 2F , the openings  216  can have a length D 6  and width D 5  and can be disposed a distance D 7  away from the center of the threaded opening  226 . Opening  226  can have a radius R 5 . In exemplary embodiments, D 5 =0.5 mm, D 6 =0.15 mm, D 7 =0.09 mm, R 5 =0.5 mm. 
     The sides  206  and  208  may have varying degrees convexity and concavity, as illustrated in  FIGS. 2B ,  2 C,  2 D, and  2 G. Referring to  FIG. 2G , the front portion  206  has a curvature radius R 8 . The back portion  208  has a curvature radius  207 . The length of the spacer  200  can be defined as the distance D from the outermost point on the left side  210  to the outermost point on the right side  212 . The width of the spacer  200  can be defined as the distance E from the outermost point in the front side  206  to the outermost point on the backside  208 . In exemplary embodiments, R 7 =25 mm, R 8 =15 mm, D=22 mm, E=10.92 mm. The various curvatures of the spinal spacer  200  can be configured to closely match the shape of the vertebrae discs of the patient. This way, the spinal spacer allows better movement and flexibility of the vertebrae with the spacer installed. As can be understood by one skilled in the art, the sides  208  and  210  may have varying heights. For example, the height of side  208  can be greater than the height of side  210 , as illustrated in  FIG. 2B . Further, in some embodiments, the height of sides  206 ,  208 ,  210 , and  212  can vary throughout the device, as desired. For example, the height of at least a portion of the side  206  can be greater than the height of at least a portion of the side  208 . The height can also vary within each side  206 ,  208 ,  210 , and  212 . This means that, for example, a portion of the left side  210  can have a lesser height than another portion of the left side  210 . Such variation in heights throughout the sides of the spinal spacer  200  can be based on a particular design choice and further configured to accommodate various dimensions of the vertebrae of the patient. Also, the thickness of the walls can vary between the sides  206 ,  208 ,  210 , and  212 . The thickness can also vary within each side  206 ,  208 ,  210 , and  212 . This means that, for example, the thickness of at least a portion of the right side  212  can greater than the thickness of at least another portion of the right side  212 . 
     The openings  216  and  226  can be located anywhere in the sides of the spacer  200 . The openings  226  may include threads  220  or any other securing patterns (mechanical locks, hooks, etc.) configured to allow insertion of screws or other devices that secure the spinal spacer  200 . 
       FIGS. 3A-4C  illustrate alternate embodiments of the spacers  300  and  400 , respectively. 
       FIGS. 3A-3G  illustrate an alternate embodiment of the spinal spacer  300 . The spinal spacer  300  is similar to the spinal spacer  100 . The spinal spacer  300  includes a top portion  302 , a bottom portion  304 , a front side  306 , a back side  308 , a left side  310 , and a right side  312 . The front side  306 , the back side  308 , the left side  310  and the right side  312  may have a varying height, length, thickness, and/or curvature radius. 
     As shown in  FIG. 3A , a combination of the sides  306 ,  308 ,  310 , and  312  forms a wall that encloses a hollow interior  322 . The top portion  302  and the bottom portion  304  include a plurality of protrusions or teeth  318  (hereinafter, referred to as “teeth”). Teeth  318  can be configured to be spaced throughout the top portion  302  and the bottom portion  304 . As can be understood by one skilled, the teeth  318  can be configured to have variable thickness, height, and width as well as angles of orientation with respect to surfaces of portions  302  and  304 . The teeth  318  can be further configured to provide additional support after the spinal spacer  300  is implanted in the vertebrae of the patient. The teeth  318  can reduce movement of the spinal spacer  300  in the vertebrae and create additional friction between the vertebrae and the spacer  300 . If more than one spinal spacer  300  is implanted in the vertebrae of the patient, the teeth  318  of one spinal spacer  300  can be configured to interact and/or mate with teeth of another spinal spacer, thereby creating stacked spacers. Such interaction can be useful, when multiple spinal spacers are needed to be implanted into the vertebrae. The teeth  318  can be configured to be similar in structure, shape, size, etc. to the teeth  118  and  218  illustrated with regard to  FIGS. 1A-2H  above. As can be understood by one skilled in the art, the teeth  318  can be configured to have any shape, size, or orientation as well as can protrude any distance away from the surfaces of the spinal spacer and can have any distance between them. 
     In some embodiments, the teeth  318  can be configured to be evenly spaced on the top portion  302  and the bottom portion  304 , such as shown in  FIGS. 4A-4C . In other embodiments, the teeth  318  can be configured to be spaced in a predetermined order, such as the one shown in  FIGS. 3A-C . 
       FIG. 3B  is a side view of the spinal spacer  300  and  FIG. 3C  is a bottom view of the spinal spacer  300  shown in  FIG. 3A . The teeth  318  are configured to be disposed on the bottom portion  304  in a predetermined order. Specifically, the teeth  318  include a plurality of spacings  335 ( a, b ) and  333 ( a, b ). The structure, disposition, orientation, and other parameters of the spacings  333  and  335  are similar to the spacings  133  and  135  discussed above. 
     As further illustrated in  FIG. 3C , some teeth  318  can have a different length than the other teeth  318 . For example, teeth located on the bottom surface  304  adjacent the right side  312  and the left side  310  can be configured to be longer than the teeth located on the bottom surface  304  adjacent the front and back portions  306 ,  308 . 
       FIG. 3D  is a side view and a cross-sectional view of the exemplary spinal spacer  300  taken at cross-section A-A. As shown in  FIGS. 3C and 3D , the wall formed adjacent to the right side  312  of the spinal spacer  300  can be configured to have a greater thickness than the walls formed adjacent to the front portion, back portion, and left side of the spacer  300 . In some embodiments, the thicknesses of the front portion, back portion, and left side can be configured to be substantially the same. As illustrated in  FIG. 3D , such thicknesses W 1  can be on the order of 0.1 mm, whereas thickness W 2  of the wall adjacent to the right side  312  can be on order of 0.19 mm. As can be understood by one skilled in the art, these numerical values are provided here for exemplary purposes only and are not intended to limit the present invention in any way. The front portion  306  and the back portion  308  can be further configured to have a convex/concave shape. The convexity/concavity of these portions can be further defined by a radius R 31 , as illustrated in  FIG. 3D . In some embodiments, both sides  312   
     Referring back to  FIG. 3A , the right side  312  can be further configured to accommodate an opening  316 . In some embodiments, the spacer  300  can be configured to include more than one opening  316 . As illustrated in  FIG. 3E , the spinal spacer  300  includes two openings  316 . The opening  316  can be configured to be for placing and maneuvering of the spacer  300  into the vertebrae of the patient. In some embodiments, the opening  316  can be configured to allow placement of the bone graft material. Further, the opening  316  can protrude through the wall of the right side  312  in such a way that it connects the hollow interior  322  with the exterior of the spacer  300 . In other embodiments, the opening  316  can be configured to be a groove, which means that the opening  316  does not protrude all the way from the exterior of the spacer  300  to the hollow interior  322 . In embodiments having more than one opening  316 , the openings can be configured to be symmetrically disposed on the right side  312 . As can be understood by one skilled in the art, the openings  316  can be disposed on any side of the spacer  300 . Additionally, as illustrated in  FIGS. 3A and 3E , the right side  312  can also include a threaded opening  326  that includes threads  320  configured to accommodate bone screws for further securing of the spacer  300  in the vertebrae of the patient. In  FIG. 3E  embodiment, the openings  316  are placed symmetrically about the threaded opening  326 . Additionally, the spacer  300  can be configured to include an opening  377  in the front side  306 . As illustrated in  FIGS. 3A and 3B , the opening  377  is configured to be located a distance D 31  from the outer edge of the right side  312 . In some embodiments, D 31 =0.33 inches and the width of the opening  377  as defined by the differences between D 32  and D 31  is on the order of 0.12 inches. The opening  377  can be configured as a partial protrusion into the front side  306 . In some embodiments, the opening  377  can be configured to connect the interior  322  of the spacer  300  to its exterior. The opening  377  can be also configured to accommodate placement and maneuvering of the spacer  300  into the vertebrae of the patient. It can also be configured to allow placement of the bone graft material. As can be understood by one skilled in the art, the spacer  300  can also include more than one opening  377 . Such openings  377  can be located anywhere (i.e., front side  406 , back side  408 , left side  410  and/or right side  412 ) in the spacer  300 . Further, the opening  377  can be located anywhere on any side of the spacer  300 . As shown in  FIG. 4A , the spacer  400  includes two openings  477  in its front side  406 . As can be understood by one skilled in the art, the openings  477  can be of the same size or different sizes. 
     The sides  306  and  308  may have varying degrees convexity and concavity, as illustrated in  FIGS. 3B ,  3 C,  3 D, and  3 G. Referring to  FIG. 3G , the front portion  306  has a curvature radius R 38 . The back portion  308  has a curvature radius R 37 . The length of the spacer  300  can be defined as the distance D 35  from the outermost point on the left side  310  to the outermost point on the right side  312 . The width of the spacer  300  can be defined as the distance D 36  from the outermost point in the front side  306  to the outermost point on the backside  308 . In exemplary embodiments, R 38 =35 mm, R 37 =15 mm, D 35 =32 mm, D 36 =10.92 mm. The various curvatures of the spinal spacer  300  can be configured to closely match the shape of the vertebrae discs of the patient. This way, the spinal spacer allows better movement and flexibility of the vertebrae with the spacer installed. As can be understood by one skilled in the art, the sides  308  and  310  may have varying heights. For example, the height of side  308  can be greater than the height of side  310 , as illustrated in  FIG. 3B . Further, in some embodiments, the height of sides  306 ,  308 ,  310 , and  312  can vary throughout the device, as desired. For example, the height of at least a portion of the side  306  can be greater than the height of at least a portion of the side  308 . The height can also vary within each side  306 ,  308 ,  310 , and  312 . This means that, for example, a portion of the left side  310  can have a lesser height than another portion of the left side  310 . Such variation in heights throughout the sides of the spinal spacer  300  can be based on a particular design choice and further configured to accommodate various dimensions of the vertebrae of the patient. Also, the thickness of the walls can vary between the sides  306 ,  308 ,  310 , and  312 . The thickness can also vary within each side  306 ,  308 ,  310 , and  312 . This means that, for example, the thickness of at least a portion of the right side  312  can greater than the thickness of at least another portion of the right side  312 . 
     As illustrated in  FIG. 3G , the front and the back sides of the spacer  300  are concave (this includes interior portions of the front and back sides). In some embodiments, the front side of the spacer can be convex and the back side of the spacer can be concave. In some embodiments, the front side of the spacer can be concave and the back side of the spacer can be convex. In yet other embodiments, both sides can be concave. Further, the interior portions of the front and back sides can be either convex, concave, or any combination of the convex/concave. The convexity/concavity of the interior portions can match the convexity/concavity of the exterior portions of the front and back sides. In some embodiments, the exterior portion of a side can be convex and the interior portion of the side can be concave and vice versa. In yet other embodiments, a side of the spacer can have multiple concave and/or convex regions. 
     Referring to  FIG. 3D , which is a side and cross-sectional view taken at line A-A, the threaded opening  326  is configured to be disposed at an angle R 33  inside the spacer  300 . Such angle can vary according to a desired configuration of the spacer  300  and in some embodiments can be on the order of 15°. Such angular disposition of the threaded opening  326  can assist a surgeon in placement and maneuvering of the spacer  300  during installation into the vertebrae of the patient.  FIG. 3C  is a side view and a cross-sectional view taken at line C-C that further illustrates threaded opening  326  having threads  320 . Referring back to  FIG. 3D , the center of threaded opening  326  can be located distance D 33  away from the edge of the opening  316 . The depth of the opening  316  can be configured to be a distance W 3  from the edge of the right side  312 . In some embodiments, D 33 =0.09 inches, W 3 =0.15 inches. As can be understood by one skilled in the art, the present invention is not limited to these dimensions. The openings  316  and  326  can be located anywhere in the sides of the spacer  300 . The openings  326  may include threads  320  or any other securing patterns (mechanical locks, hooks, etc.) configured to allow insertion of screws or other devices that secure the spinal spacer  300 . 
       FIGS. 4A-4C  illustrate spacer  400  that is similar to the spacer  300  illustrated in  FIGS. 3A-3G . One of the differences between spacers  300  and  400  is that spacer  400  includes two openings  477  as opposed to one. 
     The spinal spacer can be manufactured from a biologically accepted inert material, such as PEEK (Polyetheretherketone). The spacer can be configured to be implanted between the vertebrae for treating degenerative or ruptured discs and/or for replacing damaged vertebral bodies. As stated above, the spacer can be configured to be used singularly or in a stacked combination to fill differently sized evacuated spaces. Each spacer can be particularly shaped and sized for its particular application. 
     Example embodiments of the methods and components of the present invention have been described herein. As noted elsewhere, these example embodiments have been described for illustrative purposes only, and are not limiting. Other embodiments are possible and are covered by the invention. Such embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.