Patent Publication Number: US-2019175359-A1

Title: Pre-packed corpectomy device to improve fusion

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/217,584, filed on Jul. 22, 2016, now U.S. Pat. No. 10,206,789, which is a continuation of U.S. patent application Ser. No. 12/901,193, filed on Oct. 8, 2010, now U.S. Pat. No. 9,402,744, which claims priority to and benefit of U.S. Provisional Patent Application Ser. No. 61/397,318, filed on Jun. 11, 2010, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Field of Technology 
     This application relates generally to spinal fusion. More specifically, this application is directed to a pre-packed corpectomy device and method of bridging vertebrae with the corpectomy device to improve fusion. 
     Brief Description of Related Art 
     Spinal surgery frequently requires reconstruction of the anterior spinal column. Spinal vertebrae are bony cylindrical structures that are located in front of the spinal cord and nerves; they contribute to the structural support of the axial skeleton. A vertebra can be damaged or destroyed by disease or trauma, resulting in the compression of the spinal cord and/or loss of structural integrity of the spinal column. When the vertebra is removed during spinal surgery to decompress the spinal cord and/or restore structural integrity of the spinal column, it is necessary to reinforce and stabilize the anterior spinal column. A bone graft (e.g., from patient&#39;s hip) has traditionally been inserted into a defect site to bridge or fuse the vertebrae above and below the removed vertebra. 
     While there have been significant efforts to develop artificial weight-bearing devices, the materials that are suitable for the manufacture of these devices do not allow for bone integration. Accordingly, the devices need to have sufficient amount of interior space to pack grafting material, which can facilitate bone integration between the vertebrae. During spinal surgery, a surgical corridor is formed to the defect site, e.g., the diseased or damaged vertebra of the anterior spinal column. The corridor is generally as narrow as possible because there are sensitive and vital structures in front of the anterior spinal column that can be damaged. 
     To accommodate the materials and the surgical corridor, weight-bearing devices have been designed to have telescoping components that provide vertical expansion from a collapsed state during insertion to an expanded state after insertion into the defect site. Various expansion mechanisms have been designed to facilitate expansion and locking of the telescoping components with respect to one another. Generally, weight-bearing devices that have expansion mechanisms, which are easiest to actuate in the defect site, have the bulkiest exterior dimensions and/or take up the most interior space in the weight-bearing devices, negatively affecting fusion as they do not have sufficient amount of interior space to pack grafting material. 
     Accordingly, the following characteristics are desirable in an artificial weight-bearing device. It should have proper structural (or weight-bearing) properties. It should have a modulus of elasticity that is close to bone. It should be low profile to facilitate insertion. It should have the ability to expand after insertion into the defect site to accommodate defect sites of various patients. The expansion mechanism should be low profile and easy to actuate. The weight-bearing device should have a sufficient interior space to accommodate grafting material in order to achieve bone integration. It should further facilitate pre-packing of the grafting material before insertion into the defect site. Further, the pre-packed grafting material should be packed tightly after expansion of the device in the defect site. 
     Currently available artificial weight-bearing devices do not meet the foregoing criteria and require significant improvement. One of the most critical shortcomings is that there is little interior space for pre-packing of grafting material while the device is in a collapsed state. Further, when the device is expanded in the defect site into its expanded state, the grafting material loses its packing inside the interior space of the device. Post-packing the interior space of the device—while the device is expanded in the defect site—is not desirable and presents a danger of dislodging the device or impacting the device into the vertebrae. 
     SUMMARY 
     In accordance with an embodiment, a corpectomy device is provided. The corpectomy device includes an outer component, inner component and riser. 
     The outer component includes a first endplate and first tubular structure that extends from the first endplate. The first tubular structure includes a first end proximate the first endplate and an opposite open second end. The first tubular structure further includes a window that extends through at least a portion of a side of the first tubular structure proximate the first end. The first tubular structure further includes a seat proximate the first end and the first endplate. The seat is disposed within an inner circumference of the first tubular structure and in communication with the window. 
     The inner component of the corpectomy device includes a second endplate and second tubular structure that extends from the second endplate. The second tubular structure is at least partially disposed in the first tubular structure so that the inner component is in a first telescoping configuration with respect to the outer component. The second tubular structure defines a first terminal surface. 
     The riser of the corpectomy device has a third tubular structure that defines a second terminal surface. The riser is configured to be received through the window into the seat of the first tubular structure so that the second terminal surface engages at least a portion of the first terminal surface enabling the riser to support the inner component in a second telescoping configuration with respect to the outer component. 
     In accordance with another embodiment, a corpectomy system is provided. The system includes the corpectomy device described above, an inserter tool, and an introducer. 
     The inserter tool is configured to distract the inner component with respect to the outer component and to allow introduction of the riser into the seat of the outer component. The inserter tool includes a first arm component and second arm that is pivotally connected to the first arm component. The first arm component includes a first extension that is configured to removably engage the outer component and the second arm includes a second extension configured to extend through the outer component to removably engage the inner component. 
     The inserter tool further includes a first terminal opening, second terminal opening and an insertion surface between the first terminal opening and the second terminal opening, which are configured to communicate the riser through the inserter tool into the seat of the first tubular structure. 
     The introducer is configured to introduce the riser through the first terminal opening and the second terminal opening via the insertion surface into the seat of the first tubular structure. 
     For a more thorough understanding of the present invention, reference is made to the following description, taken in conjunction with the accompanying drawings, and its scope will be pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings in which: 
         FIG. 1  illustrates a perspective view of an example corpectomy device configured to provide sufficient interior space for pre-packing of grafting material while the device is in a collapsed state and to mitigate the loss of packing when the device is in an expanded state; 
         FIG. 2  illustrates a side view of the example corpectomy device illustrated in  FIG. 1 ; 
         FIG. 3  illustrates a perspective view of the outer component of the corpectomy device illustrated in  FIG. 1 ; 
         FIG. 4  illustrates a perspective bottom view of the outer component illustrated in  FIG. 1 ; 
         FIG. 5  illustrates a perspective view of the outer component illustrated in  FIG. 1 ; 
         FIG. 6  illustrates a cross-sectional view of the outer component of  FIG. 1  along plane B-B shown in  FIG. 5 ; 
         FIG. 7  illustrates a cross-sectional view of the outer component of  FIG. 1  along plane A-A shown in  FIG. 3 ; 
         FIG. 8  illustrates a side view of the inner component of the corpectomy device illustrated in  FIG. 1 ; 
         FIG. 9  illustrates a cross-sectional view of the inner component of  FIG. 1  along plane C-C shown in  FIG. 8 ; 
         FIG. 10  illustrates an endplate of the inner component of  FIG. 1 ; 
         FIG. 11  illustrates example risers that can be received into the outer component through a window of the outer component of  FIG. 1 ; 
         FIG. 12  illustrates the riser of  FIG. 1  in greater detail; 
         FIG. 13  illustrates cross-sectional view of the riser of  FIG. 1 ; 
         FIG. 14  illustrates a cross-sectional view of the corpectomy device of  FIG. 1  pre-packed with grafting material; 
         FIGS. 15-18  illustrate cross-sectional views of the corpectomy device of  FIG. 1  to show the insertion of the riser into the outer component to extend the corpectomy device from the collapsed configuration into the expanded configuration; 
         FIG. 19  illustrates a perspective view of another example corpectomy device that is configured to provide sufficient interior space for pre-packing of grafting material while the device is in a collapsed state and to mitigate the loss of packing when the device is in the expanded state; 
         FIG. 20  illustrates a side view of the inner component of the corpectomy device illustrated in  FIG. 19 ; 
         FIG. 21  illustrates a perspective bottom view of the inner component illustrated in  FIG. 19 ; 
         FIG. 22  illustrates a locking mechanism of  FIG. 21  in greater detail; 
         FIG. 23  illustrates the endplate of the inner component of  FIG. 19 ; 
         FIG. 24  illustrates the example riser of  FIG. 19  in greater detail; 
         FIG. 25  illustrates a cross-sectional view of the corpectomy device of  FIG. 19  that is pre-packed with grafting material; 
         FIGS. 26 and 27  illustrate cross-sectional views of the corpectomy device of  FIG. 19  to show in greater detail the insertion of the riser into the outer component to extend the corpectomy device from the collapsed state into the expanded state; 
         FIG. 28  illustrates a perspective view of an example inserter that is configured to insert the corpectomy device of  FIGS. 1 and 19  into a defect site of a spinal column and to distract the corpectomy device in the defect site; 
         FIG. 29  illustrates a perspective view of the extension member of the inserter in  FIG. 28 ; and 
         FIG. 30  illustrates a perspective view of introducing the corpectomy device of  FIGS. 1 and 19  into a defect site of a spinal column and inserting the riser of  FIGS. 1 and 19  into the corpectomy device. 
     
    
    
     DETAILED DESCRIPTION 
     A corpectomy device and method of bridging vertebrae with the corpectomy device to improve fusion are disclosed. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of example embodiments. It will be evident, however, to one skilled in the art, that an example embodiment can be practiced without all of the disclosed specific details. 
       FIG. 1  illustrates a perspective view of an example corpectomy device  100  that is configured to provide sufficient interior space for pre-packing of grafting material while the device is in a collapsed state and to mitigate the loss of packing when the device is in the expanded state. The corpectomy device  100  includes an outer component  102 , inner component  104 , and riser  106 . In various embodiments, the corpectomy device  100  described herein is configurable to achieve expansion from the collapsed state to the expanded state of between 10% and 40%, e.g., for differently-dimensioned components  102 ,  104  and riser  106 . Higher expansion between the collapsed and expanded states is feasible. 
     The corpectomy device  100  and/or components described herein are made of a material, such as a thermoplastic, a polymer, or a composite thereof, which is sufficiently resilient to withstand stress or pressure of bodily movement and positioning, while providing a degree of elasticity and also providing biostablity and biocompatibility. The material should have a modulus of elasticity that is comparable to bone. For example, corpectomy device and/or components thereof may be made of polyetheretherketone (PEEK), a thermoplastic with a Young&#39;s modulus of elasticity of about 3.6 GPa and a tensile strength of about 90 MPa. PEEK is practical because it is resistant to both organic and aqueous environments. However, other materials that may be used include metals, ceramics, medical plastics, coral, as well as other medically/surgically applicable materials, and composites thereof. 
     As will be described in greater detail with reference to the following figures, the upper and lower surfaces (endplates) of the corpectomy device  100  are configured to conform to the shape of the adjacent vertebrae (vertebral endplates) between which the corpectomy device  100  will be implanted in order to approximate and/or restore normal curvature of spine (e.g., lordosis). Further, the endplates of the corpectomy device  100  are sufficiently resilient yet open, providing weight-bearing surfaces that approximate the vertebrae and that enable bridging bone to grow through these surfaces in order to bridge the adjacent vertebrae (e.g., bone fusion). 
     The outer component  102  is configured to have a generally tubular structure. The tubular structure can have a circular or oval cross-section. In alternate embodiments, the outer component  102  can be configured to have different structures that are designed for particular patients and/or defect sites, such as hexagonal, polygonal, or other structures. A bottom portion of the outer component is capable of being pre-packed substantially with grafting material, as will be described in greater detail herein. The outer component  102  is further configured to mate with the inner component  104  in telescoping configurations, enabling the outer component  102  and inner component  104  to expand/collapse between the collapsed and expanded states. The outer component  104  includes a window  105  to receive the riser  106  to the interior of the outer component  102 . 
     The inner component  104  is also configured to have a generally tubular structure that can mate with the outer component  102  in telescoping configurations, enabling the inner component  104  and outer component  102  to expand/collapse between the collapsed and expanded states. The tubular structure can have a circular or oval cross-section. In alternate embodiments, similarly to the outer component  102 , the inner component  104  can also be configured to have different structures (e.g., hexagonal) that are designed for particular patients and/or defect sites. The inner component  104  is capable of being pre-packed substantially with grafting material. 
     The riser  106  is configured to be received securely into the outer component  102  through the window  105 . The riser  106  has a tubular structure which approximates the inner component  104 , but which is further truncated to be received through the window  105  into the outer component  102 . Similarly to the other components  102 ,  104 , the tubular structure can have an approximately circular or oval cross-section, and can also be varied based on the structure of the other components  102 ,  104  (e.g., hexagonal or other structure). After receipt into the outer component  102 , the riser  106  is further configured to provide weight-bearing support to the inner component  104  and to be locked in the outer component  102  by the inner component  104 , mitigating dislodgment of the riser  106  from the corpectomy device  100 . Similarly to the inner component  104 , the riser  106  is capable of being pre-packed substantially with grafting material. 
     The grafting material used for pre-packing can include any material that is configured to stimulate bone production through the corpectomy device  100  and fusion of the spinal vertebrae. The material can be harvested (e.g., from the patient or cadaver) or can be artificial (e.g., BPMs and other artificial materials). The grafting material can have a pasty composition (soft and spongy) or can have a more granular, fibrous and/or bony composition. The grafting material should have a consistency, which can be packed (pre-packed) tightly into the corpectomy device  100  and which can retain its shape and position in the corpectomy device during implantation. 
     In various embodiments, the dimensions of the corpectomy device  100  are approximately the following: the width of the corpectomy device  100  is between about 14 mm and 30 mm; the depth of the corpectomy device  100  is between about 10 mm to about 25 mm; and the height of the corpectomy device is between about 15 mm and about 120 mm. It is noted that the foregoing dimensions are non-limiting and may be appropriately adjusted depending on different levels of the spine (e.g., cervical, lumbar, thoracic) where the corpectomy device  100  is to be implanted, particular patient&#39;s spinal anatomy, and/or one or more other factors. 
     As will be described in greater detail with reference to the following figures, the corpectomy device  100  can be pre-packed substantially with grafting material and implanted into the defect site of the spinal column. Specifically, the corpectomy device  100  (e.g., components  102 ,  104 ) in its collapsed state can be inserted into the defect site. 
     In the defect site, the corpectomy device  100  (e.g., components  102 ,  104 ) can be distracted and the riser  106  inserted into the outer component  102 . Upon the release of the distraction, the corpectomy device  100  settles into its expanded state with the riser  106  providing weight-bearing support to the inner component  104  and the inner component  104  locking the riser  106  in the outer component  102 . 
     In the expanded state, the corpectomy device  100  (e.g., components  102 ,  104  and the riser  106 ) remains packed substantially with grafting material, mitigating the loss of packing in the expanded state experienced in the prior art systems and facilitating improved formation of bridging bone and fusion. Because no post-packing is required while the corpectomy device  100  is in the defect site, the corpectomy device  100  mitigates the possibility of dislodging from or penetrating into the vertebrae of the defect site. 
       FIG. 2  illustrates a side view of the example corpectomy device  100  illustrated in  FIG. 1 . The outer component  102  includes a first endplate  202  and first tubular structure  203 , and the inner component  104  includes an opposing second endplate  210  and second tubular structure  211 . The first endplate  202  has a first height  204  and second opposing height  206 , and the endplate  210  also has a first height  212  and second opposing height  214 . The degree of triangulation of the endplates  202 ,  210  can vary for different levels of the spine (e.g., cervical, lumbar, thoracic) and for different patients. 
     An endplate, such as first endplate  202  or second endplate  210 , will generally provide between about a zero (0) and about a six (6) degree angle with respect to a horizontal plane that bisects the corpectomy device  100 . Although the combined angle of the endplates  202 ,  210  can from about zero (0) and up to about twelve (12) degrees, the combined angle will most commonly be between about three (3) and about nine (9) degrees. Other triangulation is possible for certain patients. The triangulation of the endplates  202 ,  210  provides for the natural curvature of the spinal column at the location into which the corpectomy device  100  will be implanted. 
     The endplates  202 ,  210  include attachment devices  208 ,  116 , respectively, configured to penetrate into respective vertebrae in order to anchor the vertebrae and to induce bony ingrowths, integrating or fixating the corpectomy device  100  between vertebrae. The attachment devices  208 ,  216  can be truncated cone shapes configured to achieve penetration and anchoring. The attachment devices  208 ,  216  can be disposed in a generally circular or oval arrangement about the periphery of the endplates  202 ,  210 , as will be described in greater detail herein. Other arrangements of the attachment devices  208 ,  116  about the respective endplates  202 ,  210  are of course possible. 
     The attachment devices  208 ,  216  may be similarly or differently shaped. The shapes of the attachment devices  208 ,  216  are configured to mitigate movement of the corpectomy device  100  between the vertebrae. The attachment devices  208 ,  216  can include spikes, keels, flanges and/or other devices that can fixate the corpectomy device  100  to the vertebrae. Still further, the attachment devices  208 ,  216  can also include certain irregularities about the endplates  202 ,  210  that increase friction, such as small teeth or ridges running in the same or different directions. The teeth or ridges can be slanted with respect to endplates  202 ,  210  (e.g., like shark teeth) to better fixate the corpectomy device  100  to the vertebrae. 
     The outer component  102  has a first (front) height  218  and a second opposing (back) height  220 . The tubular structure  203  is generally of a uniform height and does not provide a height differential. Rather, the first height  218  and the second height  220  result from the triangulation of the first endplate  202  described hereinabove. Accordingly, the outer component  102  is taller in the front than in the back, which can provide for the natural curvature of the spine into which the corpectomy device  100  will be implanted. As described herein, the triangulation of the first endplate  202  can vary between about zero (0) and about six (6) degrees. 
     The window  105  has a height  222  to accommodate risers of different heights described in reference to  FIG. 11 . In some embodiments, the height  222  is about 10 mm. In other embodiments, the height  222  is between about 3 mm to about 10 mm. In still other embodiments, the height  222  can be greater than 10 mm. Different heights can be selected for the window  105  to accommodate risers of various other/additional heights. Further, the window  105  extends around at least a portion of the circumference of the first tubular structure  203 , dimensioned to accommodate the width of the risers described herein. 
       FIG. 3  illustrates a perspective view of the outer component  102  of the corpectomy device  100  illustrated in  FIG. 1 . The outer component  102  includes openings  302 ,  304 ,  306  and  308 . Central opening  302  in tubular body  203  is configured to receive the tubular body  211  of the inner component  104  and to facilitate telescoping of the inner component  104  with respect to the outer component  102  between collapsed and expanded states. 
     Opening  304  is an elongated opening that extends along the height of the outer component  102 . Opening  304  is configured to provide access to opening  906  of the inner component  104 , which will be described in greater detail below with reference to  FIG. 9 , such that the outer component  102  can be distracted with respect to the inner component  104  using an inserter tool  2800 , which is described with reference to  FIGS. 28-30 . Opening  306  is configured to removably engage an extension  2906  of the inserter tool  2800 , as further described with reference to  FIGS. 28-30 . 
     One or more openings  308  extend through the first endplate  202  and are configured to induce bony ingrowths through the openings  308  and to bridge the grafting material pre-packed in the outer component  102  of the corpectomy device  100 . 
       FIG. 4  illustrates a perspective bottom view of the outer component  100  illustrated in  FIG. 1 . The attachment devices  208  are disposed about the periphery of the first endplate  202 . The openings  308  are disposed generally centrally about the first endplate  202 . The locations and number of the openings  308  are designed to retain the substantial weight-bearing capacity of the first endplate  202 , while also providing substantial open space to induce bony ingrowths through the openings  308  to the grafting material pre-packed in outer component  102  of the corpectomy device  100 . The sizes, patterns and locations of the attachment devices  208  and the openings  308  can be varied for certain locations (defect sites) of the spinal column and/or certain patients. In certain embodiments, the attachment devices  208  can also be interspersed between the openings  308 . 
     In some embodiments as shown in  FIG. 4 , the openings  308  are disposed in generally circular/oval patterns emanating from about the center of the first endplate  202 . The openings  308  can be of the same shape or different shapes (e.g., circular, oval, square, or another shape) and can have the same or different dimensions. For example, a central opening  402  is circular and has a first diameter, openings  404  are circular and have a second diameter smaller than the first diameter, and openings  406  are circular have a third diameter smaller than the second diameter of openings  404 . Further, openings  404  are disposed about the central openings  402 , and openings  406  are disposed about the openings  404 . Other configurations of openings  308  are of course possible. 
       FIG. 5  illustrates a perspective view of the outer component  102  illustrated in  FIG. 1 . The internal structure of the outer component  102  includes opposing guide walls  502 ,  504 , ridge  506  and seat  508 . 
     The guide walls  502 ,  504  are configured to guide the riser  106  into the seat  508 . More specifically, the guide walls  502 ,  504  are sized and dimensioned to approximate the width of the riser  106  and further extend at least partially upward along the interior of the outer component  102 . Under operational constraints—when the corpectomy device  100  is under load-bearing conditions within the spinal column—the guide walls  502 ,  504  provide a backstop to the inner component  104 . In various embodiments, the guide walls  502 ,  504  can extend to different heights and up to the height of the window  105 . In some embodiments, the guide walls  502 ,  504  are of minimal height below the height of the window  105 . While it is beneficial to retain as much as possible of the interior space in the outer component  102  for the grafting material, the height of the guide walls  502 ,  504  can be determined (increased/decreased) based on the height of the riser  106  and the height of the tubular body  211  of the inner component  104  used in the corpectomy device  100 . 
     The seat  508  is recessed with respect to the window  105 , forming the ridge  506 . The seat  508  is configured to mate in a planar configuration with the riser  106 . The guide walls  502 ,  504  and the ridge  506  are configured to position the riser  106  precisely in the seat  508  of the outer component  102  in order to provide weight-bearing support to the inner component  104  via its tubular body  211 . The ridge  506  is further configured to prevent the riser  106  from dislodging out of the outer component  102  through the window  105  and into the defect site. 
     In some embodiments, at least one reinforcement band  510  can be provided to reinforce the corpectomy device  100 , preventing the rupture or failure of the outer component  102 . In some circumstances PEEK can fracture or deform (e.g., stress points, possible material deformations). In these and/or other circumstances, reinforcement can be provided to mitigate failure. The reinforcement band  510  can be made of a similar material described in relation to the corpectomy device  100 . Reinforcement bands, such as reinforcement band  510 , can be disposed at one or more locations of the outer component  102 . 
     More specifically, a band  510  can be provided at a top location as shown in  FIG. 5 , in a middle location such as between the opening  304  and the window  105 , and at a bottom location of the outer component  102  such as between the window  105  and the opening  306 . Certain of these or other locations may be indicated based on implantation into certain locations (defect sites) of the spinal column as well as certain patients, which may require additional reinforcement. While guide walls  502 ,  504  and the seat  508  provide sufficient strength at the bottom of the outer component  102 , a band  510  can further be used to provide additional reinforcement to the bottom of the outer component  102 , as desired. 
       FIG. 6  illustrates a cross-sectional view of the outer component  100  of  FIG. 1  along plane B-B shown in  FIG. 5 . The seat  508  forms an opening  602 , which is in communication with openings  302  and  308 . Opening  602  of the outer component  102  will be pre-packed substantially with grafting material to enable bridging bone to be formed through the corpectomy device  100 . Specifically, in the expanded state, the grafting material in the outer component  102 , inner component  104  and riser  106  will be contiguous to enable bridging bone to be formed through the corpectomy device  100 . 
       FIG. 7  illustrates a cross-sectional view of the outer component  102  of  FIG. 1  along plane A-A shown in  FIG. 3 . The guide walls  502 ,  504  have respective planar surfaces  702 ,  704  formed by the intersection of the guide walls  502 ,  504  with the tubular body  203  of the outer component  102 . The planar surfaces  702 ,  704  are configured to provide a backstop to (engage) the tubular body  211  of the inner component  104  in the collapsed state. The tubular body  203  of the outer component  102  further includes a top planar surface  706  configured to further provide a backstop to the second endplate  210  of the inner component  104  in the collapsed state. 
       FIG. 8  illustrates a side view of the example inner component  104  of the corpectomy device  100  illustrated in  FIG. 1 . The inner component  104  has a first (front) height  802  and a second opposing (back) height  804 . The tubular structure  211  is of a generally uniform height and does not provide a height differential. Rather, the first height  802  and the second height  804  result from the triangulation of the second endplate  210  described hereinabove. Accordingly, the inner component  104  is taller in the front than in the back, which can provide for the natural curvature of the spine into which the corpectomy device  100  will be implanted. As described herein, the triangulation of the endplate  210  can vary between about zero (0) and about six (6) degrees. 
     The second endplate  210  is wider than the second tubular structure  211  around at least a portion of the periphery of the inner component  104 , creating a lip  812  that can engage the surface  706  of the outer component  102  illustrated in  FIG. 7 . In some embodiments, the lip  812  extends around the entire periphery of the inner component  104 . In other embodiments, the lip  812  extends around the one or more portions of the periphery, such as at the oval portions of the corpectomy device  100 . In some other embodiments, the endplate  210  can be the same dimension as the tubular body  211  (similar to the outer component  102 ), thereby omitting the lip  812 . 
       FIG. 9  illustrates a cross-sectional view of the inner component  104  of  FIG. 1  along plane C-C shown in  FIG. 8 . As described earlier, the inner component  104  includes an endplate  210  and tubular body  211 . The inner component  104  further includes openings  902 ,  904 ,  906  and a planar surface  908 . 
     Central opening  902  is configured to receive grafting material into the tubular body  211  of the inner component  104 . As described earlier, the grafting material is pre-packed into the inner component  104 . To facilitate retention of the grafting material pre-packed into the inner component  104 , one or more ridges (not shown) can be provided along the central opening of the tubular body  211  (similar to ridges described with reference to the riser  106  in  FIG. 12 ). 
     Opening  904  is configured to removably engage an extension  2908  of an inserter tool  2800  described below with reference to  FIGS. 28-30 , such that the outer component  102  can be distracted with respect to the inner component  104 . In some embodiments, the opening  904  does not extend through the tubular body  211  of the inner component  104 . Under operational constraints—when the corpectomy device  100  is under load-bearing conditions within the spinal column—this mitigates the possibility of grafting material in the inner component  104  from coming out through the opening  904 . In other embodiments, the opening  906  extends through the tubular body  211  into the inner component  104 . 
     One or more openings  906  extend through the second endplate  210  and are configured to induce bony ingrowths through the openings  906  and to bridge the grafting material pre-packed in the corpectomy device  100 . 
     As will be described in greater detail below, the planar surface  908  is configured to engage the riser  106 , providing structural stability to the corpectomy device  100 , such that when the corpectomy device  100  is under operational constraints (load-bearing), sufficient pressure is provided to the pre-packed grafting material to facilitate creation of bridging bone while also providing sufficient rigidity so that the corpectomy device  100  is not crushed or does not fail in the expanded state. 
       FIG. 10  illustrates the endplate  210  of the inner component  104 . The attachment devices  216  are disposed about the periphery of the second endplate  210 . The openings  906  are disposed generally centrally about the endplate  210 . The locations and number of the openings  906  are designed to retain the substantial weight-bearing capacity of the second endplate  210 , while also providing substantial open space to induce bony ingrowths through the openings  906  to the grafting material pre-packed in inner component  104  of the corpectomy device  100 . The sizes, patterns and locations of the attachment devices  216  and the openings  906  can be varied for certain locations (defect sites) of the spinal column and/or certain patients. In certain embodiments, the attachment devices  216  can also be interspersed between the openings  906 . 
     In some embodiments as shown in  FIG. 10 , the openings  906  are disposed in generally circular/oval patterns emanating from about the center of the endplate  210 . The openings  906  can be of the same shape or different shapes (e.g., circular, oval, square, or other another shape) and can have the same or different dimensions. For example, a central opening  1002  is circular and has a first diameter, openings  1004  are circular and have a second diameter smaller than the first diameter, and openings  1006  are circular and have a third diameter smaller than the second diameter of openings  1004 . Further, openings  1004  are disposed about the central openings  1002 , and openings  1006  are disposed about the openings  1004 . Other configurations of openings  906  are of course possible. 
       FIG. 11  illustrates example risers  1102 - 1108  that can be received into the outer component  102  through the window  105 . The example riser  106  of  FIG. 1  can be any one of the example risers  1102 - 1108 . The risers  1102 - 1108  are graduated in height from about 3 mm for riser  1102  to about 10 mm or greater for riser  1108 . In some embodiments, the height-increments between the risers can be about 1 mm, while in other embodiments, the height-increments can be about 2 mm, or greater. Other intermediate or fractional height increments are of course possible. The height of the corpectomy device  100  in the expanded state can be configurable based on the height of the riser  106  (e.g., risers  1102 - 1108 ) that is used in the corpectomy device  100 . Accordingly, the corpectomy device  100  can be correctly sized for certain defect sites in the spinal column and for certain patients. 
       FIG. 12  illustrates the example riser  106  of  FIG. 1  in greater detail. The riser  106  includes opposing sidewalls  1202 ,  1204 , opposing accurate walls  1206 ,  1208 , middle wall  1210  and locking mechanism  1215 . 
     The configuration of the riser  106  approximates the configuration of the tubular body  211  of the inner component  104  (e.g., circular/oval configuration), which is truncated to create opposing sidewalls  1202 ,  1204  that are dimensioned to fit the window  105  and to be guided by guide walls  502 ,  504  into the seat  508  of the outer component  102 . 
     Opposing accurate walls  1206 ,  1208  are configured to engage the planar surface  908  of the tubular body  211  of the inner component  104 , providing structural stability to the corpectomy device  100  under operational constraints (load-bearing). 
     The middle wall  1210  is configured to provide structural stability to the riser  106 , sectioning the riser  106  into openings  1220  and  1222  that can be pre-packed with grafting material. The middle wall includes an opening  1216 , locking mechanism  1215  and retention ridges  1222 ,  1224 . 
     The opening  1216  is configured to removably engage an extension of an introducer tool  3002 , as will be described in greater detail with reference to  FIG. 30 . The opening  1216  extends through arcuate wall  1206  and partially into the middle wall  1210 . 
     The locking mechanism  1215  is configured to facilitate insertion of the riser  106  into the outer component  102  and to secure the riser  106  in the seat  508  of the outer component  102  by engaging the tubular body  211  of the inner component  104 . The locking mechanism  1215  includes a sloped surface  1212  and planar surface  1214 . During insertion, the tubular body  211  of the inner component  104  can ride or traverse along the middle wall  1210 , up the sloped surface  1212 , levelling off along planar surface  1214 , and finally locking into place via the locking mechanism  1215  along accurate wall  1206 . 
     In some embodiments, the middle wall  1210  can be omitted entirely. For example, the ridge  506  can retain the riser  106  in the seat  508  of the outer component  102  via pressure from the inner component  104  under load-bearing conditions. In other embodiments, the middle wall  1210  can be omitted partially, with the locking mechanism  1215  remaining. 
     The retention ridges  1222 ,  1224  can be provided along the bottom of the middle wall  1210  to help retain grafting material pre-packed in the respective openings  1218 ,  1220 . In other embodiments, the retention ridges  1222 ,  1224  can additionally or alternatively be provided along the bottom of the walls  1202 ,  1204 . In some embodiments, the retention ridges  1222 ,  1224  can be omitted, while still in other embodiments, the retention ridges  1222 ,  1224  can extend around the interior of the openings  1218 ,  1220 . 
       FIG. 13  illustrates a cross-sectional view of the example riser  106 . The riser  106  includes a top surface  1302  and a bottom surface  1304 . The top surface  1302  engages the planar surface  908  of the tubular body  211  of the inner component  104 , while the bottom surface  1304  engages the seat  508  of the outer component  102 . The example riser  106  provides weight-bearing support for the inner component  104  against the outer component  102 , as well as for pre-packing of grafting material to facilitate bone formation through the corpectomy device  100 . 
       FIG. 14  illustrates a cross-sectional view of an example corpectomy device  100  of  FIG. 1  that is pre-packed with grafting material. The corpectomy device  100  has been expanded slightly from its collapsed state to illustrate the pre-packing of the corpectomy device  100  in greater detail. 
     As illustrated, opening  602  of the outer component  102  is pre-packed with grafting material  1402 . The entire tubular body  211  of the inner component  104  is pre-packed with grafting material  1404 . Openings  1218 ,  1220  of the riser  106  are pre-packed with respective grafting material  1406 ,  1408 . 
     It is noted, however, that the pre-packed corpectomy device  100  in its collapsed state (inner component  104  fully inserted into outer component  102 ) is implanted into the defect site of the spinal column, then distracted sufficiently to receive the pre-packed riser  106  into the outer component  102 , and locked in its expanded state by the inner component  104  engaging the riser  106  as the distraction is released. 
       FIGS. 15-18  illustrate cross-sectional views of the corpectomy device  100  to show in greater detail the insertion of the riser  106  into the outer component  102  to extend the corpectomy device  100  from the collapsed state into the expanded state. For purposes of clear illustration, the grafting material  1402 - 1408  of the respective components  102 - 106  in the corpectomy device  100  has been removed. It is noted, however, that a pre-packed corpectomy device  100  illustrated in  FIG. 14  will be used for spinal fusion procedures. 
     At this point it is assumed that the pre-packed components  102 ,  104  of the corpectomy device  100  in a collapsed state have been inserted into proper positions in the defect site of the spinal column, with the endplates  202 ,  210  of the components  102 ,  104  contacting but not yet engaging the vertebrae of the defect site via respective attachment devices  208 ,  216 . 
     As illustrated in  FIG. 15 , the inner component  104  has been distracted sufficiently with respect to outer component  102  from the collapsed state to open at least a portion of the window  105  in the outer component  102  in order to receive the riser  106 . In this state, the attachment devices  208 ,  216  of the respective endplates  202 ,  210  in the components  102 ,  104  engage the vertebrae of the defect site. The riser  106  is inserted through the window  105  into the seat  508  of the component  102 . To facilitate insertion of the riser  106 , the surface  908  of the tubular body  211  of the inner component  104  can ride the top surface  1302  of the riser  106 . Similarly, the ridge  506  and seat  508  can ride the bottom surface  1304  of the riser  106 . 
     As illustrated in  FIG. 16 , the inner component  104  can further be distracted with respect to outer component  102  such that the surface  908  of the tubular body  211  of the inner component  104  rides up sloped surface  1212  of the riser  106  as the riser  106  is inserted into the seat  508  of the outer component  102 . 
     As illustrated in  FIG. 17 , the surface  908  of the tubular body  211  of the inner component  104  levels off on surface  1214  of the riser  106  as the riser  106  is inserted farther into the seat  508  of the outer component  102 . 
     As further illustrated in  FIG. 18 , when the locking mechanism  1215  clears the surface  908  of the tubular body  211  of the inner component  104 , the distraction with respect to components  102 ,  104  is released. As the distraction is released, the vertebrae of the defect site apply a load to the corpectomy device  100 . The surface  908  of the inner component  104  engages the top surface  1302  of the riser  106  (of walls  1206  and  1208 ) and the seat  508  of outer component  102  engages the bottom surface  1304  (of walls  1202 ,  1204 ,  1206  and  1208 ) of the riser  106 . Accordingly, the riser  106  is locked via the ridge  506  and lock  1215  in the seat  508  of the outer component  102  by the inner component  104 . 
     As shown illustrated in and described with reference to  FIGS. 15-18 , the corpectomy device  100  has been extended from a collapsed state (insertion state) into an expanded state (operational state). In the expanded state, the attachment devices  208 ,  216  of the respective endplates  202 ,  210  in the components  102 ,  104  continue to engage the vertebrae of the defect site. 
     In the expanded state, the corpectomy device  100  is under operational or load-bearing conditions within the defect site of the spinal column. The engagement of the respective components  102 ,  104 ,  106  causes their pre-packed grafting material  1402 - 1408  to be in communication throughout the corpectomy device  100 . Further, the pressure generated by the vertebrae (e.g., via ligaments, muscles) on the corpectomy device  100  pressurizes the pre-packed grafting material  1402 - 1408  throughout the corpectomy device  100 . The communication and pressurization of the pre-packed grafting material  1402 - 1408  improves formation of the bridging bone though the corpectomy device  100  and to the vertebrae of the defect site. 
       FIG. 19  illustrates a perspective view of another example corpectomy device  1900  that is configured to provide sufficient interior space for pre-packing of grafting material while the device is in a collapsed state and to mitigate the loss of packing when the device is in the expanded state. The corpectomy device  1900  includes an outer component  102 , inner component  1902 , and riser  1904 . In various embodiments, the corpectomy device  1900  described herein is configurable to achieve expansion from the collapsed state to the expanded state of between about 10% to about 40%, e.g., for differently-dimensioned components  102 ,  1902  and riser  1904 . Higher expansion between the collapsed and expanded states is feasible. 
     The corpectomy device  1900  and/or components described herein are made of similar materials described above with reference to the corpectomy device  100 , which are sufficiently resilient to withstand stress or pressure of bodily movement and positioning, while providing a degree of elasticity and providing biostablity and biocompatibility. The materials may be used include a thermoplastic (e.g., PEEK), polymer, medical plastic, coral, metal, ceramic, as well any other medically/surgically applicable material, and composites thereof. 
     The upper and lower surfaces (endplates) of the corpectomy device  1900  are configured to conform to the shape of the vertebrae (vertebral endplates) between which the corpectomy device  1900  will be implanted in order to approximate and/or restore normal curvature of spine (e.g., lordosis). Further, the endplates of the corpectomy device  1900  are sufficiently resilient yet open, providing weight-bearing surfaces that approximate the vertebrae and that enable bridging bone to grow through these surfaces in order to bridge the adjacent vertebrae (e.g., bone fusion). 
     The structure of the outer component  102  has been described in greater detail with reference to  FIGS. 1-7 . Generally, the outer component  102  has a tubular structure (e.g., circular, oval, hexagonal, polygonal or other cross-section) and at least a portion (bottom opening  602 ) of the outer component  102  can be pre-packed substantially with grafting material. The outer component  102  is configured to mate with the inner component  1902  in telescoping configurations, enabling the outer component  102  and inner component  1902  to expand/collapse between the collapsed and expanded states. The window  105  of the outer component  102  receives a riser  1904  to the interior of the outer component  102 . 
     The inner component  1902  is also configured to have a generally tubular structure (e.g., circular, oval, hexagonal, polygonal or other cross-section) that can mate with the outer component  102  in telescoping configurations, enabling the inner component  1902  and outer component  102  to expand and collapse between the collapsed and expanded states. The inner component  1902  can be pre-packed substantially with grafting material. In alternate embodiments, components  102 ,  1902  can also be configured to have different structures that are designed for particular patients and/or defect sites. 
     The riser  1904  is configured to be received securely into the outer component  102  through the window  105 . The riser  1904  can have a height described herein with reference to  FIG. 11 , or can have a different height. The riser  1904  has a tubular structure (e.g., circular, oval, hexagonal, polygonal or other cross-section), which approximates the inner component  1902 , but which is truncated to be received through the window  105  into the outer component  102 . Similarly to the other components  102 ,  1902 , the structure of the riser  1904  can also be varied based on the structure of the other components  102 ,  1902 . After receipt into the outer component  102 , the riser  1904  is further configured to provide weight-bearing support to the inner component  1902  and to be locked in the outer component  102  by the inner component  1902 , mitigating dislodgment of the riser  1904  from the corpectomy device  1900 . Similarly to the inner component  1902 , the riser  1904  can be pre-packed substantially with grafting material. 
     In various embodiments, the dimensions of the corpectomy device  1900  can be similar to or different than the dimensions of the corpectomy device  100  described herein. These dimensions are non-limiting and may be appropriately adjusted depending on different levels of the spine (e.g., cervical, lumbar, thoracic) where the corpectomy device  1900  is to be implanted, particular patient&#39;s spinal anatomy, and/or one or more other factors. 
     As will be described in greater detail with reference to the following figures, the corpectomy device  1900  can be pre-packed substantially with grafting material and implanted into a defect site of a spinal column. Specifically, the corpectomy device  1900  (e.g., components  102 ,  1902 ) in its collapsed state is inserted into the defect site. 
     In the defect site, the corpectomy device  1900  (e.g., components  102 ,  1902 ) can be distracted and the riser  1904  inserted into the outer component  102 . Upon the release of the distraction, the corpectomy device  1900  settles into its expanded state with the riser  1904  providing weight-bearing support to the inner component  1902  and the inner component  1902  locking the riser  1904  in the outer component  102 . 
     In the expanded state, the corpectomy device  1900  (e.g., components  102 ,  1902  and the riser  106 ) remains packed substantially with grafting material, mitigating the loss of packing in the expanded state experienced in the prior art systems and facilitating improved formation of bridging bone and fusion. Because no post-packing is required while the corpectomy device  1900  is in the defect site, the corpectomy device  1900  mitigates the possibility of dislodging from or penetrating into the vertebrae of the defect site. 
       FIG. 20  illustrates a side view of the example inner component  1902  of the corpectomy device  1900  illustrated in  FIG. 19 . The inner component  1902  has a first (front) height  2018  and a second opposing (back) height  2020 . The inner component  1902  includes a second endplate  2002  and second tubular body  2012 . The second endplate  2002  has a first (front) height  2004  and a second opposing (back) height  2006 . Accordingly, the inner component  1902  is taller in the front than in the back, which provides for the natural curvature of the spine into which the corpectomy device  1900  will be implanted. 
     The tubular structure  2012  is of a generally uniform height and does not provide a height differential  2018 ,  2020 . Rather, the first height  2004  and the second height  2006  result from the triangulation of the second endplate  2002  as described below in greater detail. 
     The second endplate  2002  is wider than the second tubular structure  2012  around at least a portion of the periphery of the inner component  1902 , creating a lip  2008  that can engage surface  706  of the outer component  102 . Lip  2008  can be similar to or different than the lip  812  of the inner component  104 , as described with reference to  FIG. 8 . 
     Although the first endplate  202  is described with reference to  FIGS. 1-7 , the degree of triangulation of the endplates  202 ,  2002  can vary for different levels of the spine (e.g., cervical, lumbar, thoracic) and for different patients. An endplate, such as the first endplate  202  or second endplate  2002 , will generally provide between about a zero (0) and about a six (6) degree angle with respect to a horizontal plane that bisects the corpectomy device  1900 . Although the combined angle of the endplates  202 ,  2002  can vary from about zero (0) and up to about twelve (12) degrees, the combined angle will most commonly be between about three (3) and about nine (9) degrees. Other triangulation is possible for certain patients. The triangulation of the endplates  202 ,  2002  provides for the natural curvature of the spinal column at the location into which the corpectomy device  1900  will be implanted. 
     The endplates  202 ,  2002  include attachment devices  208 ,  2010  configured to penetrate into respective vertebrae in order to anchor the vertebrae and to induce bony ingrowths, integrating or fixating the corpectomy device  1900  between vertebrae. The attachment devices  208  of the first endplate  202  were described with reference to outer component  102  of  FIGS. 1-7 . The attachment devices  2010  of the second endplate  2002  can be similar to or different than the attachment devices  216  of the second endplate  210  described hereinabove with reference to  FIG. 10 . The alternative types of attachment devices described above with reference to the attachment devices  216  are applicable with respect to the attachment devices  2010 . The attachment devices  2010  can be disposed in a generally circular or oval arrangement about the periphery of the endplate  2002 . Other arrangements of the attachment devices  2010  about the endplate  2002  are of course possible. 
     The tubular body  2012  of the inner component  1902  includes a locking mechanism  2014  configured to facilitate insertion of the riser  1904  into the outer component  102  and to secure the riser  1904  in the seat  508  by engaging the locking mechanism  2014  against the riser  1904  and the outer component  102 . The locking mechanism  2014  will be described in greater detail below with reference to  FIG. 21 . 
       FIG. 21  illustrates a perspective bottom view of the inner component  1902  illustrated in  FIG. 19 . The inner component  1902  includes openings  2102 ,  2104 ,  2106  and locking mechanism  2014 . 
     Central opening  2102  is configured to receive grafting material into the tubular body  2012  of the inner component  1902 . As described herein, grafting material is pre-packed into the inner component  1902 . 
     Opening  2104  is configured to removably engage an extension  2906  of an inserter tool  2800  described below with reference to  FIGS. 28-30 , such that the outer component  102  can be distracted with respect to the inner component  1902 . In some embodiments, the opening  2104  does not extend through the tubular body  2012  of the inner component  1902 . Under operational constraints—when the corpectomy device  1900  is under load-bearing conditions within the spinal column—this mitigates the possibility of grafting material in the inner component  1902  from coming out through the opening  2104 . In other embodiments, the opening  2104  extends through the tubular body  2012  into the inner component  1902 . 
     One or more openings  2106  extend through the endplate  2002  and are configured to induce bony ingrowths through the openings  2106  and to bridge the grafting material pre-packed in the inner component  1902  of the corpectomy device  1900 . 
     The locking mechanism  2014  includes one or more expansion slots  2108 , chamfered surface  2110 , and engagement member  2112 . As will be described in greater detail with reference to  FIG. 28 , the chamfered surface  2110  is configured to engage the riser  1904  such that when the corpectomy device  1900  is under operational constraints (load-bearing), the expansion slots  2108  allow the tubular body  2012  to expand circumferentially, engaging the engagement member  2112  against the outer component  102 . 
       FIG. 22  illustrates the locking mechanism of  FIG. 21  in greater detail. The engagement member  2112  extends about at least a portion of the circumference of the tubular body  2012 . The engagement member  2012  is generally planar and intersects the chamfered surface  2110  approximately midway along the thickness of the tubular body  2012 , as shown by the dashed lines. Other configurations of the chamfered surface  2110  and the engagement member  2012  are of course possible. 
       FIG. 23  illustrates endplate  2002  of the inner component  1902 . The attachment devices  2010  are disposed about the periphery of the endplate  2002 . The openings  2106  are disposed generally centrally about the endplate  2002 . The locations and number of the openings  2106  are designed to retain the substantial weight-bearing capacity of the endplate  2002 , while also providing substantial open space to induce bony ingrowths through the openings  2106  to the grafting material pre-packed in inner component  1902  of the corpectomy device  1900 . The sizes, patterns and locations of the attachment devices  2010  and the openings  2106  can be varied for certain locations (defect sites) of the spinal column and/or certain patients. In certain embodiments, the attachment devices  2106  can also be interspersed between the openings  2106 . 
     In some embodiments as shown in  FIG. 23 , the openings  2106  are disposed in generally circular/oval patterns emanating from about the center of the endplate  2002 . The openings  2106  can be of the same shape or different shapes (e.g., circular, oval, square, or other another shape) and can have the same or different dimensions. For example, a central opening  2302  is circular and has a first diameter, openings  2304  are circular and have a second diameter smaller than the first diameter, and openings  2306  are circular have a third diameter smaller than the second diameter of openings  2304 . Further, openings  2304  are disposed about the central openings  2302 , and openings  2306  are disposed about the openings  2304 . Other configurations of the openings  2106  are of course possible. 
       FIG. 24  illustrates the example riser  1904  of  FIG. 19  in greater detail. The riser  1904  is generally similar to risers of  FIGS. 1, 11 and 12 , except as described hereinbelow. The riser  1904  includes opposing sidewalls  2402 ,  2404 , middle wall  2406  and opposing accurate walls  2412 ,  2416 . 
     The configuration of the riser  1904  approximates the configuration of the tubular body  2012  of the inner component  1902  (e.g., circular/oval configuration), which is truncated to create the opposing sidewalls  2402 ,  2404  that are sized and dimensioned to fit the window  105  and to be guided by the guide walls  502 ,  504  into the seat  508  of the outer component  102 . 
     The middle wall  2406  is configured to provide structural stability to the riser  1904 , sectioning the riser  1904  into openings  2408  and  2410  that can be pre-packed with grafting material. The middle wall includes an opening  2420  and retention ridges  2422 ,  2424 . 
     The opening  2420  is configured to removably engage an extension of an introducer tool  3002 , as will be described in greater detail with reference to  FIG. 30 . The opening  2420  extends through arcuate wall  2412  and partially into the middle wall  2406 . 
     Opposing accurate walls  2412 ,  2416  include respective sloped surfaces  2414 ,  2418 . The accurate walls  2412 ,  2416  are configured to engage (via sloped surfaces  2414 ,  2418 ) the chamfered surface  2110  of the tubular body  2012  of the inner component  1902 , providing structural stability to the corpectomy device  1900  and locking the components of the corpectomy device  1900  ( 102 ,  1902 ,  1904 ) in respect to one another under operational constraints (load-bearing). 
     The retention ridges  2422 ,  2424  can be provided along the bottom of the middle wall  2406  to help retain grafting material pre-packed in the respective openings  2408 ,  2410 . In other embodiments, the retention ridges  2422 ,  2424  can be additionally or alternatively provided along the bottom of the walls  2402 ,  2404 . In some embodiments, the retention ridges  2422 ,  2424  are omitted, while still in other embodiments, the retention ridges  2422 ,  2424  extend around the interior of the openings  2408 ,  2410 . 
       FIG. 25  illustrates a cross-sectional view of an example corpectomy device  1900  of  FIG. 19  that is pre-packed with grafting material. The corpectomy device  1900  has been expanded slightly from its collapsed state to illustrate the pre-packing of the corpectomy device  1900  in greater detail. 
     As illustrated, opening  602  of the outer component  102  is pre-packed substantially with grafting material  2502 . The entire tubular body  2012  of the inner component  1902  is pre-packed substantially with grafting material  2504 . Openings  2408 ,  2410  of the riser  1904  are pre-packed substantially with respective grafting material  2506 ,  2508 . 
     It is noted that the pre-packed corpectomy device  1900  in its collapsed state (inner component  1902  fully inserted into outer component  102 ) is implanted into the defect site of the spinal column, then distracted sufficiently to receive the pre-packed riser  1904  into the outer component  102 , and locked in its expanded state by the inner component  1902  engaging the riser  1904  and the outer component  102  as the distraction is released. 
       FIGS. 26 and 27  illustrate cross-sectional views of the corpectomy device  1900  to show in greater detail the insertion of the riser  1904  into the outer component  102  to extend the corpectomy device  1900  from a collapsed state to an expanded state. For purposes of clear illustration, some of the grafting material  2504 - 2508  of the respective components  1902 ,  1904  in the corpectomy device  1900  has been removed. It is noted, however, that a pre-packed corpectomy device  1900  illustrated in  FIG. 25  will be used for spinal fusion procedures. 
     At this point it is assumed that the pre-packed components  102 ,  1902  of the corpectomy device  1900  in a collapsed state have been inserted into desired position in the defect site of the spinal column, with the endplates  202 ,  2002  of the components  102 ,  1902  contacting but not yet engaging the vertebrae of the defect site via respective attachment devices  208 ,  2010 . 
     As illustrated in  FIG. 26 , the inner component  1902  has been distracted sufficiently with respect to outer component  102  from the collapsed state to open at least a portion of the window  105  in the outer component  102  in order to receive the riser  1904 . In this state, the attachment devices  208 ,  2010  of the respective endplates  202 ,  2002  in the components  102 ,  1902  engage the vertebrae of the defect site. The riser  1904  is inserted through the window  105  into the seat  508  of the component  102 . 
     To facilitate insertion of the riser  1904 , the engagement member  2112  of the locking mechanism  2014  can ride the sloped surfaced  2418  and along a top surface  2602  of the riser  1904 . Similarly, the ridge  506  and seat  508  can ride along a bottom surface  2604  of the riser  1904 . As the engagement member  2112  clears the sloped surfaced  2418 , the engagement member levels off along the top surface  2602  of the riser  1904  as the riser  1904  is inserted farther into the outer component  102 . 
     As further illustrated in  FIG. 28 , when the riser  1904  is fully inserted into the seat  508  of the outer component  102  such that the chamfered surface  2110  contacts the sloped surfaces  2414 ,  2418 , the distraction with respect to components  102 ,  1902  is released. As the distraction is released, the vertebrae of the defect site apply a load to the corpectomy device  1900 . The chamfered surface  2110  engages the sloped surfaces  2414 ,  2418  of the riser  1904 , causing the tubular body  2012  of the inner component  1902  to expand circumferentially via the expansion slots  2108 . The expansion of tubular body  2012  engages the engagement member  2112  of the inner component  1902  against the outer component  102 . 
     The seat  508  of outer component  102  engages the bottom surface  2604  of the riser  1904 . Accordingly, the riser  1904  is locked via the ridge  506  and locking mechanism  2014  in the outer component  102  by the inner component  1902 . As illustrated in and described with reference to  FIGS. 25-27 , the corpectomy device  1900  has been extended from the collapsed (insertion) state into the expanded (operational) state. In the expanded state, the attachment devices  208 ,  2010  of the respective endplates  202 ,  2002  in the components  102 ,  1902  continue to engage the vertebrae of the defect site. 
     In the expanded state, the corpectomy device  1900  is under operational (load-bearing) conditions within the defect site of the spinal column. The engagement of the respective components  102 ,  1902 ,  1904  causes their pre-packed grafting material  2502 - 2508  to be in communication throughout the corpectomy device  100 . Further, the pressure generated by the vertebrae (e.g., via ligaments, muscles) on the corpectomy device  1900  pressurizes the pre-packed grafting material  2502 - 2508  throughout the corpectomy device  1900 . The communication and pressurization of the pre-packed grafting material  1402 - 1408  improves formation of the bridging bone though the corpectomy device  1900  and to the vertebrae of the defect site. 
       FIG. 28  illustrates a perspective view of an example inserter  2800  that is configured to insert the corpectomy device  100 ,  1900  into a defect site of the spinal column and to distract the corpectomy device  100 ,  1900  in the defect site. The inserter  2800  includes a handle  2802 , extension member  2804 , insertion surface  2806 , channel  2808  and fixation mechanism  2818 . 
     The handle  2802  is configured to allow the handling of the corpectomy device  100 ,  1900 . The handle  2802  includes a window  2810  that is configured to allow the riser  106 ,  1904  to be communicated or introduced through the handle  2802  and extension member  2804  into the corpectomy device  100 ,  1900 , as will be described in greater detail with reference to  FIG. 30 . The window  2810  generally approximates the dimensions of the window  105  of outer component  102  in the corpectomy device  100 ,  1900 . 
     The extension member  2804  extends from the handle  2802  and is configured to interface with the corpectomy device  100 ,  1900  to enable insertion and distraction of the corpectomy device  100 ,  1900  in the defect site, as well as the introduction of the riser  106 ,  1904  into the corpectomy device  100 ,  1900  while in the defect site. The extension member  2804  includes a fixed arm component  2812  and a movable arm  2814 . 
     The fixed arm component  2812  is configured to engage the opening  306  of the outer component  102  in the corpectomy device  100 ,  1900 , as will be described in greater detail with reference to  FIG. 29 . The movable arm  2814  is pivotally secured to the fixed arm component  2812  at location  2816  (approximately midway along the fixed arm component) within channel  2808  and configured to pivot in relation to the fixed arm component  2812  at  2816 . In some embodiments, the movable arm  2814  includes a bend at location  2815  that is displaced from location  2816 , facilitating distraction of the corpectomy device  100 ,  1900 . The movable arm  2814  is configured to extend through the opening  304  of the outer component  102  and to engage the opening  904 ,  2104  of the inner component  104 ,  1902  in the corpectomy device  100 ,  1900 , as will be described in greater detail with reference to  FIG. 29 . Upon depressing the movable arm  2814  against the handle  2802 , the corpectomy device  100 ,  1900  can be distracted to open the opening  105  in the outer component  102  to allow insertion of the riser  106 ,  1904  into the seat  508  of the outer component  102 . 
     The insertion surface  2806  extends from the opening  2810  of the handle  2802  through the end of the extension member  2804 . The insertion surface  2806  is configured to allow the riser  106 ,  1904  to be communicated or inserted through the handle  2802  and extension member  2804  into the corpectomy device  100 ,  1900 , as will be described in greater detail with reference to  FIG. 30 . 
     The channel  2808  extends along the handle  2802  and the extension member  2804 . The channel  2808  and bend in the movable arm  2814  are configured to provide a low profile extension member  2804  that allows sufficient pivoting of the movable arm  2814  with respect to the fixed arm component  2812  for distraction such that the movable arm  2814  remains mostly in the channel  2808 , mitigating contact with structures outside the surgical corridor to the defect site. 
     The fixation mechanism  2818  is configured to secure the movable arm  2814  with respect to the fixed arm component  2812  in one or more fixed relationships to facilitate insertion of the riser  106 ,  1904  into the opening  105  of the outer component  102 . In some embodiments, rotation of the fixation mechanism  2818  (clockwise and counterclockwise) can fixate and release fixation of the movable arm  2814  with respect to the fixed arm component  2812 . In other embodiments, depression of the fixation mechanism  2818  can fixate the movable arm  2814  with respect to the fixed arm component  2812  and extension of the fixation mechanism  2818  can release the fixation of the movable arm  2814  with respect to the fixed arm component  2812 . 
       FIG. 29  illustrates a perspective view of the extension member  2804  of the inserter  2800  illustrated in  FIG. 28 . The fixed arm component  2812  of the extension member  2804  further includes an interface  2902 , window  2904  and extension  2906 . 
     The interface  2902  is configured to engage the outer component  102  of the corpectomy device  100 ,  1900 . The interface  2902  is arcuate (e.g., circular, oval or another shape) to engage the outer component  102  in a planar configuration about its circumference. 
     The window  2904  is configured to allow the riser  106 ,  1904  to be communicated or introduced through into the corpectomy device  100 ,  1900 . The window  2904  approximates the dimensions of the window  105  of outer component  102  in the corpectomy device  100 ,  1900 . 
     The extension  2906  is configured to engage the opening  306  of the outer component  102  in the corpectomy device  100 ,  1900 . 
     The movable arm  2814  of the extension member  2804  includes an extension member  2908  configured to extend through opening  304  of the outer component  102  and to engage opening  904 ,  2104  of the inner component  104 ,  1902  in the corpectomy device  100 ,  1900 . 
       FIG. 30  illustrates a perspective view of inserting the corpectomy device  100 ,  1900  into a defect site of a spinal column and introducing the riser  106 ,  1904  into the corpectomy device  100 ,  1900 . 
     Initially, the corpectomy device  100 ,  1900  (outer component  102 , inner component  104 ,  1902 , riser  106 ,  1904 ) is pre-packed with grafting material as described herein. The corpectomy device  100 ,  1900  is assembled into its collapsed state (inner component  104 ,  1902  inserted into outer component  102 ; riser  106 ,  1904  being separate). 
     The extensions  2906 ,  2908  of the inserter  2800  are used to engage the openings  306 ,  904  or  2104  of the components  102 ,  104  or  1902 . The inserter  2800  is used to insert the corpectomy device  100 ,  1900  in its collapsed state into the defect site of the spinal column. The corpectomy device  100 ,  1900  can be positioned in the defect site as required. 
     After insertion, the corpectomy device  100 ,  1900  is distracted by depressing the movable arm  2814  against the handle  2802  of the inserter  2800  to open the window  105  sufficiently to receive the riser  106 ,  1904  into the seat  508  of the outer component  102 . Fixation mechanism  2818  can be used to fixate the movable arm  2814  with respect to the fixed arm component  2812  in a fixed pivotal relationship to maintain the window  105  open. 
     An introducer tool  3002  that includes an extension (not shown) is used to engage opening  1216 ,  2420  of the riser  106 ,  1904 . The introducer tool  3002  is then used to introduce the riser  106 ,  1904  into the seat  508  of the outer component  102  along the surface  2806  through openings  2810 ,  2904  and  105 . 
     After insertion of the riser  106 ,  1904  into the outer component  102 , the fixation mechanism  2818  can be released causing the corpectomy device  100 ,  1900  to settle into the expanded state (operational load-bearing state), locking the riser  106 ,  1904  in the outer component  102  as described hereinabove. The introducer tool  3002  and then the inserter  2800  are removed from the corpectomy device  100 ,  1900  and withdrawn from the defect site of the spinal column. The pre-packed corpectomy device  100 ,  1900  remains in the defect site in its operational load-bearing state, causing formation of bone (fusion) between the vertebrae of the defect site and through the corpectomy device  100 ,  1900 . 
     Thus, a pre-packed corpectomy device and method of bridging vertebrae with the corpectomy device to improve fusion have been described. Although specific example embodiments have been described, it will be evident that various modifications and changes can be made to these embodiments without departing from the broader scope of this application. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and not of limitation, specific embodiments in which the subject matter can be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments can be utilized and derived therefrom, such that structural substitutions and changes can be made without departing from the scope of this application. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. 
     Such embodiments of the inventive subject matter can be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention, inventive concept or embodiment. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose can be substituted for the specific embodiments shown. This application is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. 
     The Abstract is provided to comply with 37 CFR § 1.72(b) and will allow the reader to quickly ascertain the nature of the technical disclosure of this application. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 
     In the foregoing description of the embodiments, various features can be grouped together in a single embodiment for the purpose of streamlining the disclosure of this application. This method of disclosure is not to be interpreted as reflecting that the claimed embodiments have more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment.