Vertebral body replacement apparatus and method

Abstract

Various embodiments of the present invention relate to an apparatus for vertebral body replacement and methods associated therewith. In one embodiment, a vertebral body replacement apparatus may be used to correct and stabilize the spine (e.g., the thoracolumbar spine (T1-L5)). In another embodiment, a vertebral body (e.g., a diseased and/or damaged vertebral body) that has been resected or excised (e.g., for the treatment of a tumor or trauma) may be replaced (with the height of the resected or excised vertebral body being substantially replaced and restored by the apparatus of the present invention).

1 . A vertebral body replacement apparatus for placement between a first vertebra and a second vertebra, comprising: 
 a first endplate including a generally outward facing surface for contacting at least a portion of a lower face of the first vertebra and a generally inward facing surface including thereon at least two pockets and at least two protrusions, wherein at least one protrusion is disposed within each of the pockets;    a second endplate including a generally outward facing surface for contacting at least a portion of an upper face of the second vertebra and a generally inward facing surface including thereon at least two pockets and at least two protrusions, wherein at least one protrusion is disposed within each of the pockets;    a first lateral spacer including at least one aperture; and    a second lateral spacer including at least one aperture;    wherein, when the first and second lateral spacers are disposed between the first and second endplates such that the first endplate is above the first and second lateral spacers and the second endplate is below the first and second lateral spacers, a first pair of opposed pockets of the first and second endplates are configured to receive therein at least a part of the first lateral spacer and a second pair of opposed pockets of the first and second endplates are configured to receive therein at least a part of the second lateral spacer; and    wherein the aperture of the first lateral spacer is configured to receive at least one of the protrusions of each of the first and second endplates when the first lateral spacer is received within the first pair of pockets and the aperture of the second lateral spacer is configured to receive at least one of the protrusions of each of the first and second endplates when the second lateral spacer is received within the second pair of pockets.    
     
     
         2 . The apparatus of  claim 1 , wherein at least one of: (a) the mating of each of the protrusions with a respective one of the apertures provides lateral alignment between each of the first endplate, the second endplate, the first lateral spacer and the second lateral spacer; and (b) the mating of each of the lateral spacers with a respective pocket provides lateral alignment between each of the first endplate, the second endplate, the first lateral spacer and the second lateral spacer.  
     
     
         3 . The apparatus of  claim 2 , wherein at least one of the protrusions and at least one of a respective one of the apertures includes a locking mechanism for locking the protrusion in the aperture.  
     
     
         4 . The apparatus of  claim 3 , wherein the locking mechanism of the protrusion and the locking mechanism of the aperture are configured to permit unlocking thereof.  
     
     
         5 . The apparatus of  claim 4 , wherein the locking mechanism of the protrusion comprises a raised ridge and the locking mechanism of the aperture comprises an indentation.  
     
     
         6 . The apparatus of  claim 4 , wherein the locking mechanism of the protrusion comprises a tab and the locking mechanism of the aperture comprises a slot.  
     
     
         7 . The apparatus of  claim 1 , wherein the aperture of the first lateral spacer extends through the first lateral spacer and the aperture of the second lateral spacer extends through the second lateral spacer.  
     
     
         8 . The apparatus of  claim 1 , wherein each of the first and second lateral spacers includes a respective upper aperture adjacent the generally inward facing surface of the first endplate for receiving at least one of the protrusions of the first endplate and each of the first and second lateral spacers includes a respective lower aperture adjacent the generally inward facing surface of the second endplate for receiving at least one of the protrusions of the second endplate.  
     
     
         9 . The apparatus of  claim 1 , wherein each of the first and second lateral spacers has a lordotic angle between about 0-8 degrees.  
     
     
         10 . The apparatus of  claim 1 , wherein the generally outward facing surface of the first endplate is textured and the generally outward facing surface of the second endplate is textured.  
     
     
         11 . The apparatus of  claim 10 , wherein the texture is configured to resist expulsion of the apparatus from between the first and second vertebrae.  
     
     
         12 . The apparatus of  claim 10 , wherein the texture is configured to aid in insertion of the apparatus between the first and second vertebrae.  
     
     
         13 . The apparatus of  claim 10 , wherein the texture is configured to aid in permitting bony ingrowth from the first and second vertebrae.  
     
     
         14 . The apparatus of  claim 10 , wherein the texture is selected from the group including: (a) teeth; (b) grooves; and (c) ridges.  
     
     
         15 . The apparatus of  claim 1 , wherein the first endplate, the second endplate, the first lateral spacer and the second lateral spacer are configured to define at least one hollow area when the first and second lateral spacers are disposed between the first and second endplates such that the first endplate is above the first and second lateral spacers and the second endplate is below the first and second lateral spacers.  
     
     
         16 . The apparatus of  claim 15 , wherein the hollow area is configured to aid in permitting bony ingrowth from the first and second vertebrae.  
     
     
         17 . The apparatus of  claim 1 , wherein at least one of the first endplate, the second endplate, the first lateral spacer and the second lateral spacer comprises polyetheretherketone.  
     
     
         18 . The apparatus of  claim 1 , wherein at least one of the first endplate, the second endplate, the first lateral spacer and the second lateral spacer includes a marker comprising a material which is substantially opaque to x-rays.  
     
     
         19 . The apparatus of  claim 1 , further comprising at least one additional spacer disposed laterally between the first lateral spacer and the second lateral spacer.  
     
     
         20 . The apparatus of  claim 1 , further comprising a mechanism for connecting the apparatus to a means for supplemental fixation.  
     
     
         21 . The apparatus of  claim 20 , wherein the means for supplemental fixation is selected from the group including: (a) one or more screws; (b) one or more rods; (c) one or more staples; (d) one or more washers; (e) one or more cross connectors; and (f) one or more hooks.  
     
     
         22 . A method of constructing a vertebral body replacement apparatus for placement between a first vertebra and a second vertebra, comprising: 
 selecting a first endplate including a generally outward facing surface for contacting at least a portion of a lower face of the first vertebra and a generally inward facing surface including thereon at least two pockets and at least two protrusions, wherein at least one protrusion is disposed within each of the pockets;    selecting a second endplate including a generally outward facing surface for contacting at least a portion of an upper face of the second vertebra and a generally inward facing surface including thereon at least two pockets and at least two protrusions, wherein at least one protrusion is disposed within each of the pockets;    selecting a first lateral spacer including at least one aperture;    selecting a second lateral spacer including at least one aperture; and    placing the first and second lateral spacers between the first and second endplates such that the first endplate is above the first and second lateral spacers and the second endplate is below the first and second lateral spacers and such that a first pair of opposed pockets of the first and second endplates receive therein at least a part of the first lateral spacer and a second pair of opposed pockets of the first and second endplates receive therein at least a part of the second lateral spacer;    wherein the aperture of the first lateral spacer receives at least one of the protrusions of each of the first and second endplates when the first lateral spacer is received within the first pair of pockets and the aperture of the second lateral spacer receives at least one of the protrusions of each of the first and second endplates when the second lateral spacer is received within the second pair of pockets.    
     
     
         23 . The method of  claim 22 , wherein at least one of: (a) the mating of each of the protrusions with a respective one of the apertures provides lateral alignment between each of the first endplate, the second endplate, the first lateral spacer and the second lateral spacer; and (b) the mating of each of the lateral spacers with a respective pocket provides lateral alignment between each of the first endplate, the second endplate, the first lateral spacer and the second lateral spacer.  
     
     
         24 . The method of  claim 23 , wherein at least one of the protrusions and at least one of a respective one of the apertures includes a locking mechanism for locking the protrusion in the aperture.  
     
     
         25 . The method of  claim 24 , wherein the locking mechanism of the protrusion and the locking mechanism of the aperture are configured to permit unlocking thereof.  
     
     
         26 . The method of  claim 22 , wherein the aperture of the first lateral spacer extends through the first lateral spacer and the aperture of the second lateral spacer extends through the second lateral spacer.  
     
     
         27 . The method of  claim 22 , wherein each of the first and second lateral spacers includes a respective upper aperture adjacent the generally inward facing surface of the first endplate for receiving at least one of the protrusions of the first endplate and each of the first and second lateral spacers includes a respective lower aperture adjacent the generally inward facing surface of the second endplate for receiving at least one of the protrusions of the second endplate.  
     
     
         28 . The method of  claim 22 , wherein the steps are carried out in the order recited.  
     
     
         29 . A method of stabilizing a spine, comprising: 
 selecting, for a vertebral body replacement apparatus, a first endplate including a generally outward facing surface for contacting at least a portion of a lower face of the first vertebra and a generally inward facing surface including thereon at least two pockets and at least two protrusions, wherein at least one protrusion is disposed within each of the pockets;    selecting, for the vertebral body replacement apparatus, a second endplate including a generally outward facing surface for contacting at least a portion of an upper face of the second vertebra and a generally inward facing surface including thereon at least two pockets and at least two protrusions, wherein at least one protrusion is disposed within each of the pockets;    selecting, for the vertebral body replacement apparatus, a first lateral spacer including at least one aperture;    selecting, for the vertebral body replacement apparatus, a second lateral spacer including at least one aperture;    constructing the vertebral body replacement apparatus by placing the first and second lateral spacers between the first and second endplates such that the first endplate is above the first and second lateral spacers and the second endplate is below the first and second lateral spacers, such that a first pair of opposed pockets of the first and second endplates receive therein at least a part of the first lateral spacer and a second pair of opposed pockets of the first and second endplates receive therein at least a part of the second lateral spacer, such that the aperture of the first lateral spacer receives at least one of the protrusions of each of the first and second endplates when the first lateral spacer is received within the first pair of pockets and such that the aperture of the second lateral spacer receives at least one of the protrusions of each of the first and second endplates when the second lateral spacer is received within the second pair of pockets; and    placing the vertebral body replacement apparatus between the first and second vertebrae.    
     
     
         30 . The method of  claim 29 , wherein the vertebral body replacement apparatus is configured to be placed in one of the thoracic and lumbar spinal regions.  
     
     
         31 . The method of  claim 29 , wherein the steps are carried out in the order recited.