Abstract:
Intervertebral prosthetic systems, devices, and associated methods are provided. The present disclosure provides intervertebral prosthetic devices that include lateral plates to engage the lateral walls of the vertebral bodies for stability and include a compliant central component, fusion-cage central component, or any other suitable type of motion-preserving or fusion component positioned between the lateral plates. In some instances, the lateral plates and the central component are connected by an elongated member that extends across the disc space. The designs of the present disclosure allow insertion through a unilateral approach yet still have engagement on both sides of the vertebral body to provide stability and reduce the risk of subsidence.

Description:
TECHNICAL FIELD 
       [0001]    Embodiments of the present disclosure relate generally to intervertebral implants and associated methods of implantation and treatment. 
       BACKGROUND 
       [0002]    Within the spine, the intervertebral disc functions to stabilize and distribute forces between vertebral bodies. It comprises a nucleus pulposus which is surrounded and confined by the annulus fibrosis. Intervertebral discs are prone to injury and degeneration. For example, herniated discs typically occur when normal wear or exceptional strain causes a disc to rupture. Degenerative disc disease typically results from the normal aging process, in which the tissue gradually loses its natural water and elasticity, causing the degenerated disc to shrink and possibly rupture. Intervertebral disc injuries and degeneration may be treated by fusion of adjacent vertebral bodies or by replacing the intervertebral disc with an implant, also known as a prosthesis or prosthetic device. Generally, fusion of the adjacent vertebral bodies prevents movement between the adjacent vertebrae. Some implants, on the other hand, preserve at least some of the range of motion provided by the natural intervertebral disc. 
         [0003]    Although existing devices and methods associated within intervertebral implants have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. The intervertebral prosthetic systems, devices, and associated methods of the present disclosure overcome one or more of the shortcomings of the prior art. 
       SUMMARY 
       [0004]    The present disclosure provides intervertebral prosthetic systems, devices, and associated methods. 
         [0005]    In one embodiment, an intervertebral prosthetic device is disclosed. The intervertebral prosthetic device includes a first lateral component sized and shaped for lateral insertion through a disc space between an upper vertebra and a lower vertebra from a first lateral side of a patient and into engagement with a lateral sidewall of at least one of the upper and lower vertebra on a second lateral side of the patient opposite the first lateral side. The device also includes a second lateral component sized and shaped for lateral insertion from the first lateral side of the patient and into engagement with a lateral sidewall of at least one of the upper and lower vertebra on the second lateral side of the patient. An elongated member extends between the first lateral component and the second lateral component. The elongated member is sized to extend across the disc space between the upper vertebra and the lower vertebra when the first lateral component is engaged with the lateral sidewall on the second lateral side of the patient and the second lateral component is engaged with the lateral sidewall on the first lateral side of the patient. A central component is engaged with the elongated member and positioned between the first lateral component and the second lateral component. The central component is sized and shaped for positioning in the disc space between the upper vertebra and the lower vertebra. 
         [0006]    In some embodiments, the elongated member extends through a bore in the central component. The elongated member is movably attached to at least one of the first and second lateral components in some instances. In that regard, in some embodiments each end of the elongated member is fixedly attached to an anchor piece that is movably received within a cavity of the first and second lateral components. The anchor piece is translatable relative to the first and second lateral components within a plane defined by the cavity in some instances. In some embodiments, the first lateral component includes a first upper piece and a first lower piece, where the first upper piece movably connected to the first lower piece. In that regard, the first upper piece is pivotable and/or translatable relative to the first lower piece. Further, in some instances the lateral components each include a central portion formed of a first material and two end portions formed of a second material. In some embodiments, the first material is a resiliently flexible material (e.g., silicone, polyurethane, and other resiliently flexible materials) and the second material is more rigid than the first material (e.g., a variety of surgical-grade materials, including but not limited to stainless steel, titanium alloy, PEEK, cobalt chrome alloy, and other metal, ceramic, polymer, and/or composite materials). In some embodiments, the second lateral component includes at least one opening for receiving at least one bone anchor for fixedly securing the second lateral component to the lateral sidewall on the first lateral side of the patient. 
         [0007]    In another embodiment, a prosthetic system is disclosed. The system includes a first component sized and shaped for lateral insertion through a disc space between an upper vertebra and a lower vertebra from a first lateral side of a patient and into engagement with lateral sidewalls the upper and lower vertebra on a second lateral side of the patient. The first component is configured to be passed through the disc space in an insertion orientation relative to the upper and lower vertebrae and transitioned into an engagement orientation relative to the upper and lower vertebrae. The engagement orientation is substantially perpendicular to the insertion orientation in some instances. The system includes a second component sized and shaped for lateral insertion from the first lateral side of the patient and into engagement with lateral sidewalls of the upper and lower vertebra on the first lateral side of the patient. The system also includes a central component positioned between and in communication with the first and second components. The central component is sized and shaped for positioning in the disc space between the upper vertebra and the lower vertebra such that an upper surface of the central component engages an endplate of the upper vertebra and a lower surface of the central component engages an endplate of the lower vertebra. 
         [0008]    In some embodiments, the prosthetic system further includes an elongated member extending between the first component and the second component and extending through a portion of the central component. The elongated member is sized to extend across the disc space between the upper vertebra and the lower vertebra when the first component is engaged with the lateral sidewalls of the upper and lower vertebra on the second lateral side of the patient and the second component is engaged with the lateral sidewalls of the upper and lower vertebra on the first lateral side of the patient. The elongated member is movably attached to the first and second components in some instances. In that regard, the elongated member is fixedly attached to an anchor piece that is movably received within a cavity of each of the first and second components in some embodiments. The first and second components are each comprised of an upper piece and a lower piece that are translatable and pivotable relative to one another in some instances. In that regard, in some instances the lower pieces each include a projection and the upper pieces each include an elongated opening, where the projections of the lower pieces are received within the elongated openings of the upper pieces to facilitate the relative translation and pivoting of the upper and lower pieces. 
         [0009]    In another embodiment, a surgical method is disclosed. The method includes inserting a first lateral component through a disc space between an upper vertebra and a lower vertebra from a first lateral side of a patient in an insertion orientation relative to the upper and lower vertebrae and rotating the first lateral component from the insertion orientation to an engagement orientation, where the engagement orientation is substantially perpendicular to the insertion orientation. The method also includes engaging the first lateral component in the engagement orientation with a lateral sidewall of at least one of the upper and lower vertebrae on a second lateral side of the patient opposite the first lateral side. Further, the method includes inserting a disc component into the disc space between the upper and lower vertebrae and engaging a second lateral component with a lateral sidewall of at least one of the upper and lower vertebrae on the first lateral side of the patient. 
         [0010]    In some instances, inserting the disc component comprises advancing the disc component over an elongated member extending from the first lateral component. The method also includes engaging the elongated member with the second lateral component in some embodiments. Finally, in some embodiments engaging the second lateral component with the lateral sidewall of at least one of the upper and lower vertebrae on the first lateral side of the patient includes passing at least one bone anchor through at least one opening in the second lateral component and into the lateral sidewall of at least one of the upper and lower vertebrae on the first lateral side of the patient. 
         [0011]    Other features and advantages of the present disclosure will become apparent from the detailed description of the illustrative embodiments of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of an intervertebral prosthetic device according to one embodiment of the present disclosure. 
           [0013]      FIG. 2  is a side view of the intervertebral prosthetic device of  FIG. 1  illustrating the device relative to a pair of vertebrae after implantation. 
           [0014]      FIG. 3  is an end view of the intervertebral prosthetic device of  FIGS. 1 and 2 . 
           [0015]      FIG. 4  is a perspective view of an arrangement illustrating implantation of a first component of a prosthetic device in an insertion orientation according to one embodiment of the present disclosure. 
           [0016]      FIG. 5  is a perspective view of the arrangement of  FIG. 4  illustrating the first component of the prosthetic device in an anchoring orientation. 
           [0017]      FIG. 6  is a perspective view of the arrangement of  FIGS. 4 and 5  illustrating a central component of the prosthetic device being positioned over an elongated member of the prosthetic device extending from the first component according to one embodiment of the present disclosure. 
           [0018]      FIG. 7  is a perspective view of the arrangement of  FIGS. 4 ,  5 , and  6  illustrating implantation of a second component of the prosthetic device. 
           [0019]      FIG. 8  is a perspective view of the arrangement of  FIGS. 4 ,  5 ,  6 , and  7  illustrating the prosthetic device in a fully implanted configuration with bone anchors extending through the second component of the prosthetic device. 
           [0020]      FIG. 9  is a perspective view of an intervertebral prosthetic device according to another embodiment of the present disclosure. 
           [0021]      FIG. 10  is a side view of the intervertebral prosthetic device of  FIG. 9 . 
           [0022]      FIG. 11  is a perspective view of an intervertebral prosthetic device according to another embodiment of the present disclosure. 
           [0023]      FIG. 12  is an alternative perspective view of the intervertebral prosthetic device of  FIG. 11 . 
           [0024]      FIG. 13  is a side view of the prosthetic device of  FIGS. 11 and 12 . 
           [0025]      FIG. 14  is an end view of the prosthetic device of  FIGS. 11 ,  12 , and  13 . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications in the described devices, instruments, methods, and any further application of the principles of the disclosure as described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. 
         [0027]    Referring to  FIGS. 1 ,  2 , and  3 , shown therein is an intervertebral prosthetic device  100  according to one embodiment of the present disclosure. In particular,  FIG. 1  is a perspective view of the intervertebral prosthetic device  100 ,  FIG. 2  is a side view of the device relative to a pair of vertebrae after implantation, and  FIG. 3  is an end view of the device. 
         [0028]    The device  100  includes a lateral component  102 , a lateral component  104 , and a central component  106 . The device  100  also includes an elongated member  108  extending between the lateral components  102 ,  104 . In that regard, the ends of the elongated member  108  are secured to anchor pieces or inserts  110 ,  112  that are received within the lateral components  102 ,  104 , respectively. As discussed below, the lateral components  102 ,  104  are configured to securely engage with lateral surfaces of adjacent vertebrae on opposite sides of the vertebrae, while the central component or core  106  is positioned within a disc space between the vertebrae. In that regard, in the illustrated embodiment the device  100  includes a pair of bone anchors  114 ,  116  for securing lateral component  104  to the vertebrae. 
         [0029]    Referring more specifically to  FIG. 2 , the device  100  is illustrated in an implanted state relative to an upper vertebra  118  and a lower vertebra  120 . As shown, between the upper and lower vertebrae  118 ,  120  is a disc space  122 . In some instances, at least a portion of the natural disc is removed (e.g., discectomy) to create the disc space  122  between the upper and lower vertebrae  118 ,  120 . As shown, the upper vertebra  118  includes a lateral sidewall  124  on a first lateral side and a second lateral sidewall  126  on a second lateral side that is substantially opposite the first lateral side. Similarly, the lower vertebra  120  includes a lateral sidewall  128  on the first lateral side and a lateral sidewall  130  on the second lateral side. 
         [0030]    The lateral component  102  includes an inner surface  132  configured for engagement with the lateral sidewalls  126 ,  130  of the first and second vertebrae  118 ,  120  that are on the second lateral side. In that regard, the inner surface  132  includes engagement features  134  to encourage secure engagement between the lateral component  102  and the sidewalls  126 ,  130 . It is understood that the inner surface  132  may include any number or type of engagement features and/or surface treatments to facilitate secure engagement with the sidewalls  126 ,  130 . The illustrated engagement features  134  are shown simply to demonstrate the use of engagement features and should not be considered to limit the type or number of engagement features utilized. 
         [0031]    The lateral component  102  includes an outer surface  136  opposite the inner surface  132 . In that regard, the lateral component  102  has a thickness  138  between the inner surface  132  and the outer surface  136 . In some instances, the thickness  138  is between about 2 mm and about 8 mm and, in some particular instances, is between about 4 mm and about 6 mm. In the illustrated embodiment the thickness  138  is substantially constant along the length of the lateral component  102 . However, in other embodiments the thickness is variable along the length of the lateral component  102 . 
         [0032]    The lateral component  102  has a height  140  between an upper end  142  and a lower end  144 . In some instances, the height  140  is between about 10 mm and about 60 mm and, in some particular instances, is between about 15 mm and about 50 mm. Generally, the height  140  of the lateral component  102  is less than or equal to the length of the disc space  122  in an anterior to posterior direction but greater than the height of the disc space  122  between the vertebrae  118 ,  120  such that the lateral component  102  can be inserted through the disc space  122  in a horizontal position (as shown in  FIG. 4 ) and then rotated to a vertical position (as shown in  FIG. 5 ) after passing through the disc space. In other embodiments, the height  140  of the lateral component  102  is larger than the length of the disc space  122  in the anterior to posterior direction. In an alternative embodiment, the lateral component  102  is approximately half of the length illustrated in  FIG. 2  such that it engages with only one of the vertebrae  118 ,  120 . 
         [0033]    As shown in  FIG. 1 , the lateral component  102  has a width  145 . In some instances, the width  145  is between about 8 mm and about 40 mm and, in some particular instances, is between about 10 mm and about 30 mm. Generally, the width  145  is less than or equal to the height of the disc space  122  between the vertebrae  118 ,  120  such that the lateral component  102  can be inserted through the disc space  122  in a horizontal position (as shown in  FIG. 4 ) and then rotated to a vertical position (as shown in  FIG. 5 ) after passing through the disc space. It is understood that, in some instances, the vertebrae  118 ,  120  are distracted to increase the height of the disc space  122  to facilitate passage of the lateral component  102  through the disc space. 
         [0034]    Referring to  FIGS. 1 and 2 , the lateral component  102  also includes a cavity  146  that receives the anchor piece  110 . In the illustrated embodiment, the cavity  146  is larger than the anchor piece  110  received therein such that the anchor piece is movable relative to the lateral component  102 . In some instances, the anchor piece is translatable relative to the lateral component  102  in a plane defined by the cavity  146 . In some embodiments, the plane defined by the cavity  146  is substantially parallel to the inner and outer surfaces  132 ,  136  of the lateral component  102 . In some instances, the cavity  146  and anchor piece  110  have a structural relationship substantially similar to or identical to the structural relationship of the lateral component  104  and anchor piece  112  that is described in greater detail below with respect to  FIG. 3 . 
         [0035]    Referring again to  FIG. 2 , the lateral component  104  includes an inner surface  148  configured for engagement with the lateral sidewalls  124 ,  128  of the first and second vertebrae  118 ,  120  that are on the first lateral side. In that regard, the lateral component  104  includes openings  150 ,  152  extending between the inner surface  148  and an outer surface  154  that facilitate passage of bone anchors  114 ,  116  through the lateral component  104  and into secure engagement with the sidewalls  124 ,  128  of the vertebrae  118 ,  120 . It is understood that the inner surface  148  may include additional and or alternative types of engagement features and/or surface treatments to facilitate secure engagement with the sidewalls  124 ,  128 . Further, it is understood that the bone anchors  114 ,  116 , which are illustrated as being bone screws, may be any suitable type of bone anchor (e.g., staples, pins, etc.) for securing the lateral component  104  to the sidewalls  124 ,  128  of the vertebrae  118 ,  120 . The illustrated bone anchors  114 ,  116  are shown to demonstrate the use of bone anchors and should not be considered to limit the type or number of bone anchors utilized. 
         [0036]    The lateral component  104  has a thickness  156  between the inner surface  148  and the outer surface  154 . In some instances, the thickness  156  is between about 2 mm and about 20 mm and, in some particular instances, is between about 4 mm and about 12 mm. In the illustrated embodiment the thickness  156  is substantially constant along the length of the lateral component  104 . However, in other embodiments the thickness is variable along the length of the lateral component  104 . The lateral component  104  has a height  158  between an upper end  160  and a lower end  162 . In some instances, the height  158  is between about 10 mm and about 60 mm and, in some particular instances, is between about 15 mm and about 50 mm. Generally, the height  158  of the lateral component  104  is greater than the height of the disc space  122  between the vertebrae  118 ,  120  so that the lateral component  104  can be securely engaged with the sidewalls  124 ,  128  of the vertebrae. However, in an alternative embodiment, the lateral component  104  is approximately half of the length illustrated in  FIG. 2  such that it engages with only one of the vertebrae  118 ,  120 . As shown in  FIG. 3 , the lateral component  104  has a width  166 . In some instances, the width  166  is between about 8 mm and about 40 mm and, in some particular instances, is between about 10 mm and about 30 mm. 
         [0037]    In some instances, the lateral components  102 ,  104  have substantially similar outer profiles such that at least the heights  140 ,  158  and widths  145 ,  166  are substantially equal between the two components. However, in other embodiments the lateral components  102 ,  104  have different outer profiles such that the heights  140 ,  158  and/or widths  145 ,  166  are different between the two components. In that regard, in some instances the height  158  and/or width  166  of the lateral component  104  is greater than the height  140  and/or width  145  of the lateral component  102  since the lateral component  104  does not need to be passed through the disc space  122 . 
         [0038]    The lateral component  104  also includes a cavity  164  that receives the anchor piece  112 . As best seen in  FIG. 3 , the cavity  164  has a larger profile than the anchor piece  112  received therein such that the anchor piece is movable relative to the lateral component  102  within the cavity. As shown, the anchor piece  112  is translatable relative to the lateral component  104  in a plane defined by the cavity  164  that is substantially parallel to the inner and outer surfaces  148 ,  154  of the lateral component. In that regard, the anchor piece  112  is able to translate left and right as well as up and down relative to the lateral component  104  as viewed in  FIG. 3 . It is understood that the particular structural features of the cavity  164  and anchor piece  112  are for exemplary purposes only and in no way limit the types of cavities or anchor pieces that may be utilized. In that regard, it is understood that various types of engagements between the anchor pieces  110 ,  112  and the lateral components  102 ,  104  are utilized in other embodiments. For example, in some embodiments the structural features limit translation of the anchor component to a single direction (e.g., only translation up and down or only translation left and right as view in  FIG. 3 ). In other embodiments, the structural features allow the anchor component to pivot or be angled relative to the lateral component. 
         [0039]    Referring again to  FIG. 2 , the central component  106  includes an upper surface  168  for mating with an endplate of the upper vertebra  118  and a lower surface  170  for mating with an endplate of the lower vertebra  120 . The central component  106  also includes an opening  172  for receiving the elongated member  108 . In the illustrated embodiment the opening  172  extends through the central component from a first lateral side to an opposing second lateral side. In the illustrated embodiment the central component  106  is a compliant core. In some instances, the compliant core is formed of resiliently flexible materials that replicate the function of the natural disc. Suitable materials for the compliant core include but are not limited to polymers such as silicone, polyurethane, and other resiliently flexible materials. In other embodiments, the central component  106  is a fusion-cage or other similar fusion device designed to encourage fusion between the upper and lower vertebrae  118 ,  120 . 
         [0040]    The lateral components  102 ,  104  can be made from a variety of surgical-grade materials, including but not limited to stainless steel, titanium alloy, PEEK, cobalt chrome alloy, and other metal, ceramic, polymer, and/or composite materials. In some embodiments, the elongated member  108  is formed of flexible materials, including but not limited to polymers such as silicone, polyurethane, and other resiliently flexible materials. In other embodiments, the elongated member  108  is formed of more rigid materials, including but not limited to stainless steel, titanium alloy, PEEK, cobalt chrome alloy, and other metal, ceramic, polymer, and/or composite materials. Similarly, the anchor pieces  110 ,  112  are formed of resiliently flexible materials (including but not limited to polymers such as silicone, polyurethane, and other resiliently flexible materials) in some embodiments and formed of more rigid materials (including but not limited to stainless steel, titanium alloy, PEEK, cobalt chrome alloy, and other metal, ceramic, polymer, and/or composite materials) in other embodiments. 
         [0041]    Referring now to  FIGS. 4 ,  5 ,  6 ,  7 , and  8  shown therein are aspects of a method implanting an intervertebral prosthetic device in accordance with the present disclosure. In particular,  FIG. 4  is a perspective view of the lateral component  102  of the prosthetic device  100  in an insertion orientation;  FIG. 5  is a perspective view similar to  FIG. 4  but illustrating the lateral component  102  in an anchoring orientation;  FIG. 6  is a perspective view similar to  FIGS. 4 and 5  illustrating the central component  106  of the prosthetic device being positioned over the elongated member  108  extending from the lateral component  102 ;  FIG. 7  is a perspective view similar to  FIGS. 4 ,  5 , and  6  illustrating implantation of the lateral component  104  of the prosthetic device  100 ; and  FIG. 8  is a perspective view similar to  FIGS. 4 ,  5 ,  6 , and  7  illustrating the prosthetic device  100  in a fully implanted configuration with bone anchors  114 ,  116  extending through the lateral component  104  of the prosthetic device  100 . 
         [0042]    Referring more specifically to  FIG. 4 , the lateral component  102  is inserted between the upper vertebra  118  and the lower vertebra  120  in an insertion configuration. More specifically, the lateral component  102  is laterally inserted into the intervertebral disc space  122  between the upper and lower vertebrae  118 ,  120 . In that regard, a discectomy or other procedure for removing all or a portion of the natural disc between the upper and lower vertebrae  118 ,  120  is performed to create the intervertebral disc space  122  to allow insertion of the lateral component  102 . As shown, in the insertion configuration of  FIG. 4  the lateral component  102  is oriented in a generally horizontal direction such that upper and lower ends  142 ,  144  are positioned in an anterior-to-posterior orientation. In the insertion orientation, the lateral component  102  has a maximum height that is less than the distance between the endplates of the upper and lower vertebrae  118 ,  1120 . In that regard, the insertion configuration allows the lateral component  102  to be laterally inserted through the disc space  122  to a position adjacent the lateral sidewalls  126 ,  130  of the upper and lower vertebra  118 ,  120  opposite from the insertion point. In the illustrated embodiment of  FIG. 2 , for example, the insertion point is on the left lateral side of the patient (right side of the drawing) the lateral component  102  is passed through the disc space  122  to a position adjacent the right lateral sidewalls (left side of the drawing). It is understood that in other embodiments the insertion is from the right lateral side of the patient. Further, it is understood that the lateral insertion is either a direct lateral insertion or an oblique lateral insertion. 
         [0043]    Referring more specifically to  FIG. 5 , after the lateral component  102  has been inserted through the disc space  122  the lateral component  102  is rotated to an anchoring configuration. As shown, in the anchoring configuration of  FIG. 5  the lateral component  102  is oriented in a generally vertical direction such that the upper and lower ends  142 ,  144  are positioned in a super-to-inferior orientation. In the illustrated embodiment, the lateral component  102  is rotated approximately 90 degrees between the insertion configuration and the anchoring configuration. Rotation of the lateral component  102  is accomplished utilizing any suitable surgical tool. In some instances, a surgical tool engages the opening in the inner surface  132  defined by the cavity  146 . In that regard, the tool utilized to insert the lateral component  102  can also be utilized to rotate the lateral component between the insertion and anchoring configurations. 
         [0044]    In the anchoring configuration a portion of the inner surface  132  of the lateral component  102  adjacent the upper end  142  engages the sidewall  126  of the upper vertebra  118  while a portion of the inner surface  132  adjacent the lower end  144  engages the sidewall  130  of the lower vertebra  120 . In that regard, the lateral component  102  is sized such that it spans across the disc space  122  between the vertebrae  118 ,  120  in the anchoring configuration. In some instances, a plurality of lateral components of varying sizes (e.g., lengths and/or widths) are provided and medical personnel selects the appropriate sized lateral component  102  based on the anatomy of the patient. 
         [0045]    Referring to  FIG. 6 , the central component  106  is inserted over the elongated member  108  extending from the lateral component  102 . In some embodiments, the elongated member  108  and/or the central component  106  include features that facilitate engagement of the central component  106  at a particular location along the length of the elongated member  108 . For example, in some instances the elongated member  108  includes one or more projections that are configured for engagement with corresponding recesses within surfaces of the central component  106  defining the opening  172  such that engagement of the projection(s) and recess(es) holds the central component  106  in a fixed position along the length of the elongated member. In other instances, the central component  106  is allowed to translate along the length of the elongated member  108  after implantation. For example, in some instances the upper and lower surfaces  168 ,  170  of the central component  106  are shaped such that the central component is self-centering relative to the upper and lower vertebrae  118 ,  120 . That is, while the central component  106  will move about the disc space  122  between the vertebrae  118 ,  120 , the shape of the central component  106  results in the central component naturally returning to a desired, centralized location within the disc space. 
         [0046]    Referring now to  FIG. 7 , with the central component  106  positioned over the elongated member  108  the lateral component  104  is engaged with the free end of the elongated member. In that regard, in some instances the elongated member  108  is secured to the anchor piece  112  that is positioned within the cavity  164  of the lateral component  104 . In some embodiments, the elongated member  108  is passed through an opening in the anchor piece  112  and secured to the anchor piece by crimping, gluing, fastening, or otherwise fixedly attaching the elongated member to the anchor piece. In some instances, the elongated member  108  is pulled through the anchor piece  112  with sufficient tension to encourage fixed engagement of the lateral component  102  with the sidewalls  126 ,  130 . Excess portions of the elongated member  108  are cut off in some instances such that the elongated member does not extend beyond the lateral component  104 . Referring to  FIG. 8 , with the lateral component  104  positioned adjacent to the lateral surfaces  124 ,  128  of the upper and lower vertebrae  118 ,  120 , the bone anchors  114 ,  116  are inserted through the openings  150 ,  152  and into engagement with the upper and lower vertebrae. 
         [0047]    In other instances, the intervertebral prosthetic device  100  is assembled (i.e., lateral components  102 ,  104 , central component  106 , and elongated member  108  are assembled together) prior to implantation. In that regard, the entire device  100  may be inserted in an insertion configuration and then rotated to an anchoring configuration after the lateral component  102  passes through the disc space. Alternatively, with the device  100  assembled the lateral component  102  can be positioned in the insertion configuration illustrated in  FIG. 4 , inserted through the disc space  122 , and then rotated to the anchoring configuration illustrated in  FIG. 5 . 
         [0048]    As noted above, in alternative embodiments, either one or both of the lateral components  102 ,  104  is sized such that it engages with only one of the vertebrae  118 ,  120 . Such embodiments can allow greater range of motion between the vertebrae  118 ,  120  as compared to the lateral components  102 ,  104  that engage both vertebrae. 
         [0049]    As shown, the prosthetic devices and associated methods of the present disclosure facilitate lateral insertion of intervertebral prosthetic devices from a single side of the patient. More specifically, the devices and methods of the present disclosure require access from a single lateral direction, but still facilitate secure engagement of the prosthetic devices with both lateral sides of the vertebrae. Further, a direct lateral approach for lumbar spine surgery offers many benefits. For example, a direct lateral approach can overcome the risks associated with an anterior approach and the space limitations of a posterior approach. 
         [0050]    Referring now to  FIGS. 9 and 10 , shown therein is an alternative embodiment of an intervertebral prosthetic device  200  according to the present disclosure. In that regard,  FIG. 9  is a perspective view of the prosthetic device  200  and  FIG. 10  is a side view of the prosthetic device  200 . As shown, the prosthetic device  200  includes a lateral component  202 , a lateral component  204 , and a central component  206 . The device  200  also includes an elongated member  208  extending between the lateral components  202 ,  204 . The lateral components  202 ,  204  are configured to securely engage with lateral surfaces of adjacent vertebrae  118 ,  120  on opposite sides of the vertebrae, while the central component or core  106  is positioned within the disc space  122  between the vertebrae. In that regard, in the illustrated embodiment the device  200  includes a pair of bone anchors  214 ,  216  for securing lateral component  204  to the sidewalls  124 ,  128  of the vertebrae  118 ,  120 . 
         [0051]    The lateral component  202  includes a central portion  218  bounded by an upper portion  220  and a lower portion  222 . The upper portion  220  extends between the central portion  218  and an upper end  224  of the lateral component  202 , while the lower portion  222  extends between the central portion  218  and a lower end  226 . Similarly, the lateral component  204  includes a central portion  228  bounded by an upper portion  230  and a lower portion  232 . The upper portion  230  extends between the central portion  228  and an upper end  234  of the lateral component  204 , while the lower portion  232  extends between the central portion  228  and a lower end  236 . The upper portion  230  includes an opening  238  and the lower portion  232  includes an opening  240  for receiving the bone anchors  214 ,  216 , respectively. 
         [0052]    In the embodiment of  FIGS. 9 and 10 , the central portions  218 ,  228  are formed of a resiliently flexible material such that the lateral components  202 ,  204  allow at least some motion between the vertebrae  118 ,  120  after implantation. In that regard, in some instances the resiliently flexible central portions  218 ,  228  allow movement between the vertebrae  118 ,  120  associated with flexion, extension, and/or rotation. In some instances, the central portions  218 ,  228  allow movement in one or more directions but limit or prevent movement in one or more other directions. 
         [0053]    The upper portions  220 ,  230  and the lower portions  222 ,  232  are formed of materials having increased rigidity and/or hardness relative to the central portions  218 ,  228 . In that regard, the increased rigidity and/or hardness of the upper and lower portions  220 ,  222 ,  230 ,  232  facilitate secure engagement with the upper and lower vertebrae  118 ,  120 . In some embodiments, the upper and lower portions  220 ,  222 ,  230 ,  232  are formed of stainless steel, titanium carbide, cobalt chrome alloy, ceramic, PEEK, UHMWPE, and other metal, ceramic, polymer, and/or composite materials having increased rigidity relative to the central portions  218 ,  228 . 
         [0054]    Referring now to  FIGS. 11 ,  12 ,  13 , and  14 , shown therein is another embodiment of an intervertebral prosthetic device  300  according to the present disclosure. Specifically,  FIG. 11  is a perspective view of the intervertebral prosthetic device  300 ;  FIG. 12  is an alternative perspective view of the device;  FIG. 13  is a side view of the device; and  FIG. 14  is an end view of the device. 
         [0055]    Referring more specifically to  FIGS. 11 ,  12 , and  13 , the prosthetic device  300  includes a lateral component  302 , a lateral component  304 , and a core  306 . The device  300  also includes an elongated member  308  extending between the lateral components  302 ,  304 . The lateral components  302 ,  304  are configured to securely engage with lateral surfaces of adjacent vertebrae  118 ,  120  on opposite sides of the vertebrae, while the core  306  is positioned within the disc space  122  between the vertebrae. In that regard, in the illustrated embodiment the device  300  includes a pair of bone anchors  314 ,  316  for securing lateral component  304  to the sidewalls  124 ,  128  of the vertebrae  118 ,  120 . 
         [0056]    As shown, the lateral component  302  includes an upper piece  318  and a lower piece  320 . As best seen in  FIGS. 12 and 13 , the upper piece  318  includes an inner surface  322  for engaging with the sidewall  126  of the upper vertebra  118 . In that regard, the inner surface  322  includes engagement features  324  to facilitate fixed engagement of the upper piece  318  with the upper vertebra  118 . As best seen in  FIGS. 11 and 13 , the upper piece  318  also includes an outer surface  326  opposite the inner surface  322 . An elongated opening  328  extends along the length of the upper piece  318  between the inner surface  322  and the outer surface  326 . In the illustrated embodiment, the surfaces defining the elongated opening  328  taper inward from both the inner surface  322  and the outer surface  326 , as shown in  FIGS. 11 and 12 . The elongated opening  328  extends along a majority of the length of the upper component  318  between an upper end  330  and a lower end  332 . 
         [0057]    The lower piece  320  includes an inner surface  334  for engaging with the sidewall  130  of the lower vertebra  120 . In that regard, the inner surface  334  includes engagement features  336  to facilitate fixed engagement of the lower piece  320  with the lower vertebra  120 . As best seen in  FIGS. 11 and 13 , the lower piece  320  also includes an outer surface  338  opposite the inner surface  334 . A projection  340  extends outward from the outer surface  338  of the lower piece  320 . The projection  340  of the lower piece is received within the elongated recess  328  of the upper piece  318 . In that regard, the projection  340  has an inner surface  342  that is contoured to generally match the taper of the surfaces defining elongated opening  328  such that the projection  340  is translatable and pivotable relative to the upper piece  318  within the elongated opening  328 . In the illustrated embodiment, the projection  340  is positioned closer to the upper end  344  of the lower component  320  than the lower end  346 . In some instances, the projection  340  is positioned along the length of the lower piece  320  between the upper end  344  and the lower end  346  such that it is substantially aligned with the disc space  122  between the vertebrae  118 ,  120  when the prosthetic device  300  is in a neutral position. 
         [0058]    Referring still to  FIGS. 11 ,  12 , and  13 , the lateral component  304  also includes an upper piece  348  and a lower piece  350 . As best seen in  FIGS. 11 and 13 , the upper piece  348  includes an inner surface  352  for engaging with the sidewall  124  of the upper vertebra  118 . In that regard, a bore  354  extends through the upper piece  348  from the inner surface  352  to an outer surface  356 . The bore  354  is configured to receive the bone anchor  314  to facilitate fixed engagement of the upper piece  348  with the upper vertebra  118 . An elongated opening  358  extends along the length of the upper piece  348  between the inner surface  352  and the outer surface  356 . In the illustrated embodiment, the surfaces defining the elongated opening  358  taper inward from both the inner surface  352  and the outer surface  356 , as shown in  FIGS. 11 and 12 . The elongated opening  358  extends along a majority of the length of the upper component  348  between an upper end  360  and a lower end  362 . 
         [0059]    The lower piece  350  includes an inner surface  364  for engaging with the sidewall  128  of the lower vertebra  120 . In that regard, a bore  366  extends through the lower piece  350  from the inner surface  364  to an outer surface  368 . The bore  366  is configured to receive the bone anchor  316  to facilitate fixed engagement of the lower piece  350  with the lower vertebra  120 . A projection  370  extends outward from the outer surface  368  of the lower piece  350 . The projection  370  of the lower piece  350  is received within the elongated recess  358  of the upper piece  348 . In that regard, the projection  370  has a contoured inner surface  372  that generally matches the taper of the surfaces defining elongated opening  358  such that the projection  370  is translatable and pivotable relative to the upper piece  348  within the elongated opening  358 . In the illustrated embodiment, the projection  370  is positioned closer to the upper end  374  of the lower component  350  than the lower end  376 . In some instances, the projection  370  is positioned along the length of the lower piece  350  between the upper end  374  and the lower end  376  such that it is substantially aligned with the disc space  122  between the vertebrae  118 ,  120  when the prosthetic device  300  is in a neutral position. 
         [0060]    Referring now to  FIG. 14 , as described above the engagement of the projections  340 ,  370  of the lower pieces  320 ,  350  with the elongated recesses  328 ,  358  of the upper pieces  318 ,  348  allow the upper and lower pieces to translate and pivot with respect to one another. Such relative movement will be discussed in greater detail in the context of the upper piece  348  and the lower piece  350  as shown in  FIG. 14 . In that regard, the upper and lower pieces  348 ,  350  are able translate with respect to one another along the longitudinal axis  378 . Further, the upper and lower pieces  348 ,  350  are able to pivot with respect to one another. Generally, the projection  370  serves as the pivot point between the pieces  348 ,  350 . In that regard, the phantom depiction of the upper piece illustrates an orientation of the upper piece  348  relative to the lower piece  350  in one pivoted position. As shown the longitudinal axis  380  of the upper piece  348  extends at an angle  382  relative to the longitudinal axis of the lower piece  350 , which is represented by axis  378 . It is understood that the orientation illustrated in  FIG. 14  is for exemplary purposes only and is not limiting to the directions in which the pieces  348 ,  350  can pivot relative to one another. In that regard, it is understood that the upper piece  348  can pivot in the other direction (left as viewed in  FIG. 14 ) relative to the lower piece  350  as well. It is also understood that both upper and lower pieces  348 ,  350  may pivot relative to a longitudinal axis of the spinal column. 
         [0061]    The engagement of the projection  370  with the elongated recess  358  can limit the amount of angulation or pivot allowed between the pieces  348 ,  350 . In some embodiments, the maximum angulation allowed between the pieces  348 ,  350  is 45 degrees or less in either direction. Engagement of the projection  370  with the elongated recess  358  also limit the amount of translation allowed between the pieces  348 ,  350 . In that regard, the length and/or the positioning of the elongated recess  358  on the upper piece  348  in combination with the size and/or the positioning of the projection  370  on the lower piece  350  are utilized to define the amount of translation permitted between the upper and lower pieces  348 ,  350 . 
         [0062]    Although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure and in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. It is understood that such variations may be made in the foregoing without departing from the scope of the embodiment. In that regard, it is fully contemplated that generally any of the features described with respect to one of the prosthetic devices above may be combined with features of one or more of the other prosthetic devices described above. Further, it is understood that embodiments described has having upper and lower components and/or left and right components and/or other similar directional components are inverted in some instances such that the upper component becomes the lower component and vice versa and/or features of the upper component become features of the lower component and vice versa. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the present disclosure.