Patent Publication Number: US-2012029640-A1

Title: Vertebral implant end cap

Description:
BACKGROUND 
     The present application is directed to implants, devices and methods for stabilizing vertebral members, and more particularly, to intervertebral implants, devices and methods of use in replacing an intervertebral disc, a vertebral member, or a combination of both to distract and/or stabilize the spine. 
     The spine is divided into four regions comprising the cervical, thoracic, lumbar, and sacrococcygeal regions. The cervical region includes the top seven vertebral members identified as C1-C7. The thoracic region includes the next twelve vertebral members identified as T1-T12. The lumbar region includes five vertebral members L1-L5. The sacrococcygeal region includes nine fused vertebral members that form the sacrum and the coccyx. The vertebral members of the spine are aligned in a curved configuration that includes a cervical curve, thoracic curve, and lumbosacral curve. Intervertebral discs are positioned between the vertebral members and permit flexion, extension, lateral bending, and rotation. 
     Various conditions and ailments may lead to damage of the spine, intervertebral discs and/or the vertebral members. The damage may result from a variety of causes including, but not limited to, events such as trauma, a degenerative condition, a tumor, or infection. Damage to the intervertebral discs and vertebral members can lead to pain, neurological deficit, and/or loss of motion of the spinal elements. 
     Various procedures include replacing a section of or the entire vertebral member, a section of or the entire intervertebral disc, or both. One or more replacement implants may be inserted to replace the damaged vertebral members and/or discs. The implants are configured to be inserted into the intervertebral space and contact against adjacent vertebral members. The implants are intended to reduce or eliminate the pain and neurological deficit, and increase the range of motion. 
     The curvature of the spine and general shapes of the vertebral members may make it difficult for the implants to adequately contact the adjacent vertebral members or to position the adjacent vertebral members in a desired orientation. There is a need for implants or devices configurable to match the spinal anatomy for secure contact and/or desired orientation for secure contact when implanted into an intervertebral space. 
     SUMMARY 
     The present application discloses implants or devices for insertion into an intervertebral space between a first and second vertebral member, the implant comprising an implant body having a base section with at least first and second base teeth, and corresponding securing depressions adjacent the first and second base teeth. The end cap is adapted for selective axial positioning at a selected point on the base section via rotational adjustment of the end cap about an implant axis. The end cap and comprises an exterior contact surface that faces away from the implant body and a seating surface adapted to contact the base section when the end cap is positioned on the implant body. The end cap also comprises an end cap angulation, a fixed aperture adapted to receive a corresponding first base extension, and a variable aperture adapted to receive a corresponding second base extension. The variable aperture includes a flexible aperture finger having an aperture finger tip that extends through a seating surface plane away from the seating surface. The fixed aperture and variable aperture are configured to complementarily engage corresponding first and second base extensions, and the flexible aperture finger is adapted to engage a corresponding securing depression, via the aperture finger tip, to securely maintain the end cap positioned on the base section in a locked position. When the implant is positioned in the intervertebral space in a locked position, the implant will impart the end cap angulation to an adjacent vertebral body at the selected point. 
     The present application also discloses an end cap for use with an implant having a base section with at a plurality of base extensions and corresponding securing depressions. The end cap is axially placed on the base section and rotationally positioned or moved into a secure or locked position on the base section. The end cap comprising . . . an exterior contact surface, a seating surface, and a substantially vertical exterior cap wall extending between the exterior contact surface and the seating surface. The end cap also comprises a fixed aperture extending between the exterior contact surface and the seating surface and adapted to receive a corresponding first base extension, and a variable aperture extending between the exterior contact surface and the seating surface and adapted to receive a corresponding second base extension. The variable aperture includes a flexible aperture finger having an aperture finger tip that extends through a seating surface plane away from the seating surface. The fixed aperture and variable aperture are configured to complementarily engage corresponding first and second base extensions, and the flexible aperture finger engages a corresponding securing depression via the aperture finger tip to securely maintain the end cap positioned on the base section. The fixed and variable apertures enable the end cap to be axially positioned at a selected point on the implant base section. The end cap, once securely positioned on the implant, will impart an end cap angulation to an adjacent vertebral body at the selected point. 
     There is also provided a method of assembling an implant for insertion into an intervertebral space between a first and second vertebral member. The method comprising positioning an end cap at an end of an implant body, the end cap having a fixed aperture adapted to receive a corresponding first base extension that extends from the implant body and a variable aperture adapted to receive a corresponding second base extension that extends from the implant body; axially inserting the first and second base extensions into a corresponding end cap fixed aperture and variable aperture; rotating the end cap relative to the implant body to thereby simultaneously move the first and second base extensions into corresponding fixed and variable apertures, and a flexible aperture finger into engagement with a corresponding end cap securing depression via an aperture finger tip; positioning an aperture protrusion that extends from an aperture sidewall of the fixed aperture in a tooth undercut section; and securing the first and second base extensions within the corresponding fixed and variable apertures, and securing the flexible aperture finger within the corresponding end cap securing depression to thereby position the end cap to the implant body in a locked position. 
     The various aspects of the various embodiments may be used alone or in any combination, as is desired. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an implant according to one embodiment positioned in an intervertebral space between vertebral members; 
         FIG. 2  is a perspective view of an implant with an end cap attached thereon according to one embodiment; 
         FIG. 3  is an exploded perspective view of the implant and end cap of  FIG. 2 ; 
         FIG. 4  is a top view of the implant and an end cap of  FIG. 2 ; 
         FIG. 5  is a section view along the line A-A of the implant and end cap of  FIG. 4 ; 
         FIG. 6  is a perspective view of an implant end cap according to one embodiment; 
         FIG. 7  is a top view of the end cap of  FIG. 6 ; 
         FIG. 8  is a side view of the end cap of  FIG. 6 ; and 
         FIG. 9  is a top view of an implant base section according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present application is directed to intervertebral implants for spacing apart vertebral members  100  and  105 .  FIG. 1  shows an implant  10  positioned within an intervertebral space  101  formed between vertebral members  100  and  105 . The implant  10  includes an implant body  20  and one or more end caps  40  and  42  which are attached to the implant body  20  at a first or second implant base section  15  and  25  via base teeth or base extensions  30 . The end caps can be an upper end cap  40  or a lower end cap  42 . The one or more end caps  40  and  42  will attach or connect to the implant body  20  to impart a desired or selected angulation θ, an angular orientation and/or an end cap position to the adjacent vertebral member  100  or  105 . A first and second securing or locking mechanism  50  and  60 , shown in one aspect in  FIGS. 2 ,  4  and  5  engages and locks the end cap  40  and  42  to the implant base section  15  and  25 . This will improve the contact and stability of the intervertebral implant  10  to the adjacent vertebral members  100  and  105  and drive angular orientation and position for correction and/or improved alignment of the spine. 
     As shown in  FIG. 1 , the implant  10  may include first and second end caps  40  and  42  positioned at opposite ends of the implant body  20  at first and second base sections  15  and  25 . The first end cap may be an upper end cap  40  and the second end cap may be a lower end cap  42 . A first end cap  40  can have an angulation θ of zero degrees and a first end cap height H 1 , as shown in  FIGS. 1-3 ,  5  and  8 . The second end cap  42  can have an angulation θ greater than zero degrees, for example of 15° degrees, and a second height H 2 . Those of skill in the art will recognize that the first and second end caps  40  or  42  may have the same or different configuration, heights H, and/or the same or different end cap angulation θ. Further, although two end caps  40  and  42  are shown in the disclosed aspects, those of skill in the art will recognize that one or two end caps  40  or  42  may instead be used in a medical procedure with the implant  10 , and that the end caps can be attached to either the first and second base sections  15  and  25 , to impart desired or needed heights H and angulation θ to adjacent vertebral members  100  or  105  to thereby correct, improve and/or stabilize the affected spinal anatomy. 
       FIGS. 2-3  illustrate assembled and exploded perspective views of an implant  10  with upper and lower end caps  40  and  42  according to one embodiment.  FIG. 4  is a top view of the assembled implant  10  and end caps  40  and  42  of  FIG. 2 .  FIG. 5  is section view along the line A-A of the assembled implant  10  and end caps  40  and  42  shown in  FIG. 2  showing in more detail securing or locking mechanism a with a first securing feature  50  and second securing feature  60 .  FIG. 6  is a perspective view of the end cap  40  showing in more detail end cap fixed apertures  45 , an open aperture  61  and an end cap securing finger  65  having an aperture finger tip  67 .  FIG. 9  is a top view of an implant base section  15  showing in more detail a plurality of securing depressions or indentations  35  formed around the periphery or exterior edge of the base section support surface  16  which are adapted to accept and locking engage the securing finger  65  when the end cap  40  or  42  is securely positioned on the base section  15  or  25 . 
     The implant body  20  in combination with the end caps  40  and  42  is sized to fit within the intervertebral space  101 . In this aspect, the implant body  20  is constructed of two implant sections  22  and  24  which are movable relative to each other to permit axial adjustment of the overall axial height of the implant  10 . The implant body  20  includes an inner implant body  22  adapted to axially travel inside an outer implant body  24  to thereby enable selected or controlled collapse and expansion of the implant  10 . The outer implant body  24  includes a hollow interior and the inner implant body  22  includes a first base section  15 . The inner implant body  22  is sized to fit within and axially travel along the hollow interior of the outer implant body  24  to adjust the height of the implant body  20  along the longitudinal axis  5 . The inner body  22  includes a neck area with a plurality of scallops  21  that extend along the length of the inner body  22 . Both the inner and outer implant bodies  22  and  24  may be hollow and include one or more apertures to receive bone growth material. Also, one or more apertures may extend through the body  20  walls to the hollow interior. The implant body  20  may also be constructed from a single section with a fixed height measured between the first and second base sections  15  and  25 . 
     A securing mechanism  23  may secure the inner and outer sections  22  and  24  together to fix the height. In one embodiment, the securing mechanism  23  is configured to receive one or more cylindrical rods (not illustrated) that seat within the plurality of scallops  21  that extend along the inner body  22  neck. U.S. Patent Publication No. 2008/0114467 discloses embodiments of an implant that may be used with end caps and include a multiple-section body and a locking mechanism and is herein incorporate by reference in its entirety. 
       FIGS. 2-5  and  9  illustrate the implant body  20  which is configured to receive an end cap  40  or  42  at the first and second base sections  15  and  25 . The first and second base sections  15  and  25  have an exterior support surface or support surface  16  that extends around the periphery of a corresponding central base aperture  17 . In the disclosed embodiment, the support surface  16  is substantially flat, although other embodiments may include a variety of different surface configurations. 
       FIGS. 2-5  and  9  also show that the base sections  15  and  25  include a plurality of base teeth or base extensions  30  that extend axially away or outward from the support surface  16 . The base extensions  30  are preferably evenly spaced around the periphery of the base section  15  and  25  and extend away from an exterior surface  16  of the first base section  15  in a substantially outward or axial direction. The base extensions  30  are sized and configured to extend into corresponding end cap locking apertures or passages  45  or  61  when the end cap  40  or  42  is positioned onto the base section  15  and  25 . The outer implant body  24  includes a second base section  25  with similarly positioned and configured base teeth  30 .  FIGS. 2 ,  3 ,  4  and  9  illustrate an embodiment where the implant base sections  40  or  42  have six (6) extending base teeth or base extensions  30  that are equidistantly spaced about the support surface  16  about or around the periphery of the central base aperture  17 . As such, in this embodiment, the six extending base teeth  30  are spaced at or about 60° apart from each other around the periphery of the implant base section  15  or  25 . 
     Other base section  15  or  25  embodiments are contemplated which could include at least two or more than two base extensions  30 . In such a case, there must be at least the same number of locking aperture or passages  45  and  61  to accept the base extensions  30 . There could also be more locking aperture or passages  45  and  61  than base teeth  30  which will result in greater degree of control in axial placement of the end cap  40  or  42  on the base section  15  or  25 . Further, other contemplated embodiments include base extensions  30  which are non-equidistantly spaced about the support surface  16  about or around the periphery of the central base aperture  17 . In such cases, the locking aperture or passages  45  and  61  will be spaced or located at corresponding non-equidistant points around the end cap area between the vertical exterior cap wall  44  and the central aperture  43  to accept the base teeth  30 . In the non-equidistant spacing case, the locking apertures  45  and  61  need to be spaced and located to complementarily align with the spacing and location of the base teeth  30  to permit axial end cap  40  insertion and rotational engagement with the base teeth  30  of the implant base section  15  or  25 . 
       FIGS. 2-5  and  9  further show that the base sections  15  and  25  include a plurality of securing depressions or indentations  35  formed into and extending axially and downwardly away from the support surface  16  in a substantially opposite direction relative to the base extensions  30 . The securing depressions or indentations  35  are preferably evenly spaced and located around the periphery or exterior edge of the base section  15  &amp;  25  and extend away from the exterior base section support surface  16  in a substantially downward axial direction relative to the base teeth or base extensions  30 . In one aspect, best shown in  FIGS. 2-3  and  9 , the securing depressions or indentations  35  preferably lie adjacent to the base teeth or base extensions  30  and below a plane (not shown) substantially defined by the base section support surface  16 . Further, the securing depressions or indentations  35  comprise a securing depression entry or opening  37  which lies in the plane defined by the base section support surface  16 . The securing depressions or indentations  35  are sized, configured and adapted to accept and lockingly engage the securing finger  65  when the end cap  40  or  42  is securely positioned on the base section  15  or  25 . The outer implant body  24  also includes a second base section  25  with similarly positioned and configured securing depressions or indentations  35 .  FIGS. 2 ,  3  and  9  illustrate an embodiment where the implant base sections  40  or  42  have six (6) securing depressions or indentations  35  that are equidistantly spaced about the support surface  16  about or around the periphery of the central base aperture  17  and adjacent the corresponding six (6) base teeth  30 . As such, in this embodiment, the six securing depressions or indentations  35  are spaced at or about 60° apart from each other around the periphery of the implant base section  15  or  25  and adjacent to the corresponding six (6) base teeth  30 , as best shown in  FIG. 9 . 
     In other base section  15  embodiments which include at least two or more than two base extensions  30 , the number of securing depressions or indentations  35  are preferably adjacent to and are the same quantity as the number of base extensions  30 . In such a manner, there would preferably be corresponding securing depressions or indentations  35  which are adjacent to each base section  30  so as to be able to accept and lockingly engage the securing finger  65  at each base tooth  30  location when the end cap  40  or  42  is securely positioned on the base section  15  or  25 . Having less securing depressions or indentations  35  than base teeth  30  will prevent locking engagement of the securing finger  65  at each base tooth  30  position. As a result, in the disclosed aspect, there is preferably the same number of securing depressions or indentations  35  as base teeth  30 , and the securing depressions or indentations  35  are preferably adjacent to the base teeth  30  as best shown in  FIG. 9 . 
     The implant base section&#39;s  15  and  25  central base aperture  17 , shown in  FIGS. 2 ,  3  and  5 , is adapted to receive or permit delivery of bone growth material into the implant  10  which will augment fusion in the disc space  101  once the implant is in place between the vertebral members  100  and  105 . The base apertures  17  are preferably adjacent and aligned with a corresponding end cap central aperture  43 . Those of skill in the art will recognize that the base aperture  17  and end cap central apertures  43  may also be non-aligned if desired or needed by a surgeon, medical procedure or clinical application. 
     Additionally, the base teeth or base extensions  30  include a tooth base or stem  28  that extends axially outward from the support surface  16  and are capped with a tooth head  29 . The tooth head  29  includes a tapered shape or configuration, for example similar to a solid cone shape, that terminates at a tip. The tooth head tip facilitates entry and travel into a corresponding end cap locking aperture or passage  45  or  61  when the end cap  40  or  42  is positioned and placed on the base section  15  and  25 . The tooth head tip may also be appropriately shaped to directly contact against and/or penetrate into an adjacent vertebral member  100  or  105  when the implant  10  is used without an end cap  40 , or when the base tooth or base extension  30  extends beyond the end cap  40 . As best illustrated in  FIGS. 3 and 5 , the tooth base or stem  28  comprises a smaller width than the tooth head  29  forming an undercut tooth section or notch  31 . The depth of the undercut tooth section  31  may be the same or different for each of the base teeth or base extensions  30 . The undercut tooth sections  31  may face radially outward from the central base aperture  17 . One or more base teeth or base extensions  30  may include a tooth base or stem  28  that have substantially the same width as the tooth head  29 . In one embodiment, the width of the tooth stem  28  is equal to the widest part of the tooth head  29 . 
     The end cap  40  or  42 , via its end cap locking apertures or passages  45 , can be attached to the implant body  20  via the base teeth or base extensions  30  and securing depressions or indentations  35  when the end cap  40  or  42  is placed and positioned on the base section  15  and  25 . The overall width or distance across the end cap  40  or  42  preferably matches the width or distance across the base section  15  and  25  such that the end cap  40  or  42  does not extend past the lateral side walls of the implant body  20 . In other embodiments, the end cap  40  or  42  may have a width or distance across the end cap  40  or  42  that is greater or smaller than width or distance across the base section  15  and  25  such that the end cap  40  or  42  would extend or would not extend, respectively, past the lateral side walls of the implant body  20  depending on the desire or needed of a surgeon, medical procedure or clinical application. 
       FIGS. 2-4  and  6 - 7  illustrate that the end cap  40  comprises an annular or circular like shape with an outside or exterior contact surface  48 , locking apertures or passages  45  and  61 , an interior or seating surface  41 , a substantially vertical exterior end cap wall  44  and a central aperture  43 . The end cap  40  may take on a variety of geometric shapes desired or needed by a surgeon, medical procedure or clinical application. Other shapes include but are not limited to polygonal and crescent-shaped. The end cap  30  may also include a central aperture  43  that may also have various geometric shapes. 
     The exterior contact surface  48  and the seating surface  41  are bounded by the vertical exterior end cap wall  44  and the central aperture  43 . The seating surface  41  is preferably substantially flat to complementarily abut against the exterior support surface  16  of the implant base section  15  or  25 . In a preferred aspect, the seating surface  41  and the exterior surface  16  have complementary and substantially flat surfaces such that the end cap  40  can seat flush on the implant base section  15  when placed in an engaged and locking position. The exterior contact surface  48  extends around the central aperture  43 . The exterior contact surface  48  may be flat, or may include various other configurations to facilitate contact with the vertebral member  100  or  105 . Those of skill in the art will recognize that the seating surface  41  and exterior contact surface  48  may take on other configurations as may be desired or needed by a surgeon, medical procedure or clinical application. The central aperture  43  is preferably aligned with and the same size as the corresponding base aperture  17 . The central aperture  43  and base aperture  17  may also be of different sizes and non-aligned if desired or needed by a surgeon, medical procedure or clinical application. 
     The exterior contact surface  48  includes end cap teeth  49  which will engage the end plates of an adjacent vertebral member  100  or  105  to assist the implant  10  grip the vertebral member end plate, provide implant  10  stability in the disc space  101 , and prevent implant  10  ejection from the intervertebral space  101 . The end cap teeth or spikes  49  may be a series of equidistantly spaced end cap teeth or spikes  49  extending from the end cap exterior surface  48 , as shown in  FIGS. 2-7 . Those of skill in the art will recognize that the number, size, shape, orientation and spacing of the end cap teeth  49  may vary according to the needs of a medical procedure, clinical application, or surgeon need or selection. For example, the end cap teeth or spikes  49  could also be a series or pattern of uniform knurls and spikes  49  (not shown) that cover the end cap exterior surface  48  and assist in providing a securing and stabilizing function of the combined end cap  40  or  42  and implant body  20  or solely a series or pattern of uniform knurls (not shown) that cover the end cap exterior surface  48 , so long as they assist in providing a securing and stabilizing function of the combined end cap  40  or  42  and implant body  20 . Those of skill in the art will recognize that the number, size, height, shape, orientation and spacing of the end cap teeth or spikes  49  may vary according to the needs of a medical procedure or clinical application. 
     The end cap teeth  49  may contact the adjacent vertebral member  100  or  105  and/or penetrate into the vertebral member  100  or  105  as may be desired or required by a physician or medical procedure or clinical application. In one aspect, the end cap teeth or spikes  49  will come in contact with and engage the end plates of an adjacent vertebral body  100  or  105  once the combined implant body  10  and end cap  40  or  42  are positioned in an intervertebral space  101  between the vertebral members  100  and  105 . The end cap teeth or spikes  49  will extend from the end cap exterior surface  48  sufficiently to grip, penetrate and embed into the adjacent vertebral member  100  and  105  end plate to thereby provide implant stability in the intervertebral disc space  101  and prevent the inserted implant  10  from being ejected out of the intervertebral space  101  after implant  10  insertion. The end cap teeth or spikes  49  will provide a securing and stabilizing function of the combined end cap  40  and implant body  10 . The actual height of the end cap teeth or spikes  49  can vary to accommodate the selection or need of a surgeon, medical procedure or clinical application. When an implant  10 , with positioning base teeth  30  and one or two end caps  40  or  42 , is inserted into an intervertebral space  101  and set to a desired implant height, via appropriate instruments (not shown), the protruding end cap teeth or spikes  49  will grip and/or penetrate into the adjacent vertebral member end plate to maintain a stable implant  10  position between the adjacent vertebral members  100  and  105 . 
     The end cap  40  or  42  preferably further comprises an angulation aspect θ and an end cap vertex height H. The end cap angulation θ and cap height H may have a range of values as may be selected or needed by a surgeon, medical procedure or clinical application. In one aspect, preferred discrete values for end cap angulation are 0°, 4°, 8° and 15° degrees measured from an angulation reference line X, shown in  FIG. 1 . In other embodiments, the preferred angulation θ values may be in the range of zero and thirty degrees (0°-30°), with a preferred range of between zero and fifteen degrees (0°-15°). In one aspect, the cap height H may have preferred values in 1.0 mm or 0.5 mm increments measured from the end cap seating surface  41 . The angulation reference line X is preferably at the cap height H value as shown in  FIG. 1 . The end cap&#39;s angulation θ is a measure of the inclination of the exterior contact surface  48  relative to the angulation reference line X. Insertion of an implant  10  with an end cap  40  or  42  having an angulation θ aspect enables the end cap  40  or  42  to impart a desired or selected angulation θ to an adjacent vertebral member  100  or  105 . In this manner, selective angulation θ can be imparted to the adjacent vertebral body  100  or  105  and thereby assist in the correction and/or improved orientation, stabilization and alignment of the spine. In the event where additional implant height H is desired or required without any angulation, an end cap  40  having angulation θ of 0° degrees may be used to impart the additional height to the implant  10  in the amount of an end cap height H. Such a case is illustrated in  FIGS. 2-3 ,  5 - 6  and  8  which show views of an implant base section  15  with an end cap  40  having angulation θ of 0° degrees and a certain cap height H 1 . Additionally, selected angulation θ may advantageously and appropriately accommodate the lordotic or kyphotic shape of the spine depending upon the vertebral level at which the implant  10  is to be positioned in the patient. 
       FIGS. 1-3  show a first or upper end cap  40  and a second or lower end cap  42 . The first and second end caps  40  or  42  may have the same or different configuration, heights H, and/or the same or different end cap angulation θ. As shown in  FIGS. 1-3 , the upper end cap  40  has an angulation θ of zero degrees and a first end cap height H 1 .  FIGS. 1-3  show that the lower end cap  42  has an angulation θ greater than zero degrees (0°) and a second height H 2 . As noted previously, values for an end cap angulation can be 0°, 4°, 8° and 15° degrees measured from an angulation reference line X, or values in a range of zero and thirty degrees (0°-30°), with a preferred range of between zero and fifteen degrees (0°-15°). Those of skill in the art will recognize that end caps  40  or  42  with the same or different end cap angulation θ and the same or different end cap heights H 1  or H 2  may instead be used. Although two end caps  40  and  42  are shown in the disclosed aspects, those of skill in the art will also recognize that one end cap may instead be used, either as a lower or upper end cap, in a medical procedure with the implant  10  to impart desired or needed height H and angulation θ to adjacent vertebral members  100  or  105  and thereby correct, improve and/or stabilize the affected spinal anatomy. 
       FIGS. 1-3  show an aspect where the upper end cap  40  provides an angulation θ of zero degrees (0°) and is attached to the inner implant body  22  at the upper implant base section  15 . In this aspect, the upper end cap  40  provides an end cap height H 1  but will not provide any implant angulation θ. Such an end cap  40  may be used where there is a need only for additional height to augment the implant  10  in the amount of an end cap height H 1  as might be desired or required by a surgeon, medical procedure or clinical application.  FIGS. 1-3  also show an aspect where the lower end cap  42  provides an angulation θ greater than zero degrees (θ&gt;0°) and attached to the outer implant body  24  at the lower implant base section  25 . In this aspect, the lower end cap  42  provides an end cap height H 2  and an implant angulation θ&gt;0°. Such an end cap  42  may be used where there is a need for both additional height to augment the implant  10  in the amount of end cap height H 2  and end cap angulation θ greater than zero degrees (θ&gt;0°) as might be desired or required by a surgeon, medical procedure or clinical application. 
       FIGS. 2-4  and  6 - 8  show an end cap  40  which includes one or more locking apertures or passages  45  or  61  that receive corresponding base teeth  30  extending from the implant body  20  base sections  15  or  25 . The locking apertures  45  or  61  are spaced around the end cap  40  or  42  to complementarily correspond to and accommodate the positioning of the base teeth or base extensions  30  extending from the base sections  15  or  25  and corresponding adjacent base section securing depressions  35  when the end cap  40  or  42  is axially placed and then rotationally positioned on the implant body  20 . In one aspect, shown in  FIGS. 2-4  and  6 - 7 , the fixed or closed apertures  45  comprise a continuous sidewall  56 . The apertures  45  include a wide section  51  and a narrow section  53 . The wide section  51  includes a greater width measured between opposing surfaces than the narrow section  53 . The wide section  51  is wider than the base tooth head  29  of the base extension  30  to allow the end cap  40  or  42  to be axially mounted onto the implant body  20 . The narrow section  53  is narrower than the base tooth head  29  which thereby permits the end cap  40  or  42  to be rotationally positioned and secured to the implant body  20 . 
     An aperture protrusion or projection  57  extends into the aperture  45  from the sidewall  56  to form the edge of the narrow section  53 . The aperture protrusion  57  is configured to fit within the undercut section  31  below the tooth head  29  of the base tooth or base extension  30  to attach and secure the end cap  40  or  42  to the implant body  20 . The aperture protrusion  57  is located or recessed below the end cap exterior surface  48 . This recessed positioning locates the aperture protrusion  57  such that it can fit under the tooth head  29  of the base tooth or base extension  30  and within the undercut section  31  when the end cap  40  or  42  is attached, rotationally positioned and secured to the implant body  20 , as best shown in  FIG. 5 . 
     When the end cap  40  or  42  is axially positioned on the base section  15  or  30 , the base extensions  30  will enter into a corresponding wide section  51  of the one or more end cap apertures  45 . Once the end cap  40  or  42  is axially seated on the exterior surface  16  of the implant base section  15  or  25 , the base extensions  30  are located in the wide section  51  of a corresponding fixed aperture  45 . The end cap  40  or  42  and/or the implant base section  15  or  25  can then be appropriately rotated, in one aspect disclosed in a clockwise direction, so that the aperture protrusion  57  will travel until the aperture protrusion  57  is in complementary and mechanical communication with the undercut section  31  of the base tooth or base extension  30  in the narrow section  53  of the and cap aperture  45 , as shown in  FIGS. 2 ,  4  and  5 . Once the end cap  40  or  42  is in the narrow section  53  of the fixed aperture  45 , if the positioning teeth  30  continue to travel in the aperture  45 , the positioning teeth  30  will reach and abut up against a narrow section stop wall  59  located opposite the wide section  51  of the fixed aperture  45 . When the base teeth  30  reach and abut up against the aperture stop wall  59 , the aperture stop wall  59  will obstruct and prevent further travel of the positioning teeth  30  inside the fixed aperture  45 . If an attempt is made to continue to rotationally move or force the end cap  40  or  42  to travel on the implant base section  15  or  25 , the aperture stop wall  59  will prevent further travel of the positioning tooth  30 . The end cap  40  or  42  has reached a secured or locked position, shown in  FIGS. 2 and 4 , on the implant body base section  15  or  25 . At this point, as shown in  FIG. 5 , the aperture protrusion  57  is in complementary and mechanical communication with the undercut section  31  of the base tooth or base extension  30  below the tooth head  29 . The mechanical communication between the aperture protrusion  57 , the undercut section  31 , the tooth head  29  and aperture stop wall  59  can comprise a first securing or locking mechanism  50 . 
     In the secured or locked position, the end cap  40  or  42  is in an engaged or locked position relative to the implant body  20 . The aperture protrusion  57  and the undercut section  31  are preferably and complementarily sized such that, at the engaged and locked position, e.g., as shown in FIGS,  2 ,  4  and  5 , the fit between the aperture protrusion  57  and the undercut section  31 , and by extension the positioning teeth  30  and fixed apertures  45  is a friction fit. The friction fit should permit the positioning teeth  30  to travel inside the narrow sections  57  so that the aperture protrusion  431  and the undercut section  31  can reach an engaged or locked position when the end cap  40  or  42  is moved relative to the first or second base section  15  or  25  towards the aperture stop walls  59 . The friction fit, when the aperture protrusion  57  and the undercut section  31  are in mechanical communication should be sufficiently strong to minimize or significantly retard rotational movement between the positioning teeth  30  and fixed end cap apertures  45  once the end cap  40  or  42  is positioned in the engaged or locked position cap position on the first or second base section  15  or  25 . 
     The friction locking aspect can form part off the first securing locking mechanism  50 . The holding strength of the friction fit between the positioning teeth  30  and end cap apertures  45 , via the aperture protrusion  57  and the undercut section  31 , may be augmented or controlled by the addition or use of a coating or adhesive substance between the aperture protrusion  57  and the undercut section  31 . For example, a coating, such a silicone, or an adhesives such as an epoxy, may be used to increase friction between the aperture protrusion  57  and the undercut section  31 . Those of skill in the art will recognize that other substances or friction control mechanisms may be used to augment or control friction strength between the end cap slots  45  and the positioning teeth  30 , such as roughened surfaces, dissimilar materials, and shape differences. 
     The complementary and mechanical communication between the aperture protrusion  57  and the undercut section  31  will prevent axial movement or travel of the end cap  40  or  42  away from the implant base section  15  or  25  along the implant axis  5 . This is the case since the aperture protrusion  57  is now positioned underneath and obstructed by the base extension head  29 . An attempt to axially move or remove the end cap  40  or  42  away from the implant base section would result in the aperture protrusions  57  bumping into and abutting the underside of the teeth heads in the undercut sections  31 . The teeth heads  29  thus prevent axial movement of the end cap  40  or  42  away from the implant base section  15  or  25  along the implant axis  5  once the end cap  40  or  42  is in a secured or locked position with the base section  15  or  25 . The number of fixed apertures  45  in an end cap  40  or  42  may vary from a single to multiple apertures  45 .  FIGS. 2-7  illustrate an embodiment with five (5) axially attaching and rotationally positioning fixed or closed apertures  45 . 
       FIGS. 2-8  show that the end cap  40  or  42  further includes a variable aperture  61  that is adapted to receive a corresponding base tooth or base extension  30  extending from the implant body  20  base sections  15  or  25  and engage and interact with a corresponding securing depressions  35  adjacent to the corresponding base tooth  30 . The variable aperture  61  will simultaneously act in combination with the one or more end cap fixed apertures  45  to enable the end cap  40  or  42  to be axially attached, rotationally positioned and secured to the implant body  20  when the end cap  40  or  42  is axially placed and positioned on the base teeth  30  of the implant body base sections  15  or  25 .  FIGS. 2-7  show an embodiment with a single variable aperture  61  adapted to receive a corresponding base tooth or base extension  30  extending from the implant body  20  base sections  15  or  25  when the end cap  40  or  42  is axially attached on the implant body  20 . However, the end cap  40  or  42  may have one or more variable apertures  61 .  FIGS. 2-8  show that the single variable aperture  61  is adapted to engage and interact with a corresponding securing depressions  35  adjacent to the corresponding base tooth  30  when the end cap  40  or  42  is axially attached and rotationally secured to the implant body  20 .  FIGS. 2-7  show an embodiment of an end cap  40  or  42  with five fixed apertures  45  and one variable aperture  61 . Those of skill in the art will recognize that an end cap  40  or  42  could have a varying combination of fixed and variable apertures  45  and  61  where there are the same or a different number of fixed apertures  45  and variable apertures  61  as might be desired or needed by a surgeon, medical procedure or clinical application. For example, in another aspect, the end cap  40  or  42  could instead have four fixed apertures  45  and two variable apertures  61 . Further, the fixed apertures  45  and variable aperture  61  may have the same or different shape, configuration and/or sizes. 
     As best shown in  FIGS. 6-8 , the variable aperture  61  preferably comprises a first interior space  62 , an aperture slot  63 , a second interior space  64 , an aperture finger  65 , aperture finger tip  67  and a variable aperture stop wall  67  adjacent the aperture slot  63 . The first interior space  62  is wider than the base tooth head  29  of the base extension  30  to allow the end cap  40  or  42  to be axially mounted onto the implant body  20 . The second interior space  64  is preferably sized to accommodate the base tooth head  29  when the end cap  40  or  42  is rotated into a locked position and secured to implant body  20 , as best shown in  FIG. 4 . The aperture slot  63  extends between the second interior space  64  and the exterior edge of the end cap wall  44 , and between the finger tip  67  and the variable aperture stop wall  69 . The aperture slot  63 , first interior space  62  and second interior space  64  are in spatial orientation with each other so that the flexible aperture finger  65  is formed in an exterior portion of the variable aperture  61  along a portion of the end cap&#39;s  40  or  42  exterior end cap wall  44 . 
     Additionally, the aperture finger  62  comprises an aperture finger tip  67 . The aperture slot  63  and second interior space  64  are in spatial orientation with each other so that the aperture finger tip  67  is formed in an exterior portion of the variable aperture  61  adjacent to the aperture slot  63  and along a portion of the end cap&#39;s  40  or  42  exterior end cap wall  44 . The aperture finger tip  67  extends in an axially downward direction such that the aperture finger  67  extends below a plane (not shown) defined by the end cap seating surface  41 , as best shown in  FIGS. 2 and 8 . The aperture finger tip  67  will complementarily and mechanically interact and engage with base section&#39;s  15  or  25  securing depressions or indentations  35  once the end cap  40  or  42  is axially positioned on the base section  15  or  30  and rotationally moved towards the end cap&#39;s  40  or  42  secured or locked position, as shown in  FIGS. 2-4  and  6 - 7 , on the implant body base section  15  or  25 . The securing finger  65  and corresponding securing depressions or indentations  35  should be complementarily sized and configured so that the securing finger  65  can enter and engage a corresponding securing depression  35  to securely engage or lock the end cap  40  or  42  to the base section  15  or  25 . 
       FIGS. 2-8  show an embodiment with a single variable aperture  61  having a corresponding single aperture finger  65  adapted to receive and engage a corresponding base tooth  30  extending from the implant body  20  base sections  15  or  25  when the end cap  40  or  42  is axially attached and rotationally secured on the implant body  20 . The end cap  40  or  42  may, in other aspects, have more than one variable apertures  61  which in turn leads to having more than one corresponding aperture finger  67 .  FIGS. 2-7  show an embodiment of an end cap  40  or  42  with five fixed apertures  45  and one variable aperture  61  with its single corresponding aperture finger  65 . In another aspect, for example, the end cap  40  or  42  could have four fixed apertures  45  and two variable apertures  61  with two corresponding aperture fingers  65 . Those of skill in the art will recognize that an end cap  40  or  42  could have a varying combination of fixed and variable apertures  45  &amp;  61  and corresponding aperture fingers  65  where there are the same or a different number of fixed apertures  45 , variable apertures  61  and aperture fingers  65  as might be desired or needed by a surgeon, medical procedure or clinical application. 
     The material or composition make up of the end cap  40  or  42 , and the relative position and configurations of the variable aperture  61 , slot  63  and first and second interior space  62  and  64  result in an aperture finger  65  which has physical characteristics and properties whereby the aperture finger  65  is flexible and moveable. In this manner, the aperture finger  65  can move, flex or deflect from an original equilibrium or static position if a deflecting force is encountered by the aperture finger  65 . When the end cap  40  or  42  is axially placed on the base section  15  or  25 , the aperture finger  65  will encounter a deflecting force sufficient to overcome its stationary or static position and/or relative inertia, the aperture finger  65  will move or deflect in an axial upward direction Y depicted in  FIGS. 8 . The upward force is provided by the base station support surface  16  which pushes up against the aperture finger tip  67  when the end cap  40  or  42  is axially placed on the base section  15  or  25 . The aperture finger  67  experiences this force because the aperture finger tip  67  extends downward below the plane (not shown) defined by the end cap seating surface  41 , as best shown in  FIGS. 2 and 8 . Since the end cap seating surface  41  preferably must rests substantially flush or flat on the base section support surface  16  to permit rotation of the end cap  40  or  42  into a secured or locked position, then the support surface  16  must push upwards on the aperture finger tip  67  and the aperture finger tip  67  must flex upward so that the seating surface  41  can appropriate seat substantially flush on the base section support  16 . This flexibility enables the aperture finger  65  to move or deflect axially to thereby permit the end cap  40  or  42  to be axially positioned on the base section  15  or  25  and thereafter to permit the end cap  40  or  42  to rotationally travel towards a locked position, shown in  FIGS. 2 and 4  where the end cap  40  or  42  was axially attached and then rotationally positioned on the implant body  20  base section  15  or  25 . 
     The variable aperture finger  65 , aperture finger tip  67  and variable aperture stop wall  69  interact and cooperate with a corresponding positioning tooth  30  and base section securing depression or indentation  35  when the end cap  40  or  42  is axially placed or attached onto the base section  15  or  25  and then rotationally positioned in the implant base section  15  or  25 . The variable aperture  61  is sized to permit a positioning tooth  30  to axially enter and slideably travel within the variable aperture passage  61  as the end cap  40  or  42  is axially placed on the base section  15  or  25  and then rotationally positioned or rotated on the base sections  15  or  25 . The positioning tooth  30 , base section securing depression  35 , variable aperture  61 , the variable aperture finger  65 , aperture finger tip  66  and variable aperture stop wall  69  enable the end cap  40  or  42  to be axially place onto and then rotationally positioned on the base section  15  or  25  to thereby form a second locking feature or end cap locking mechanism  60 , shown in  FIGS. 2 ,  4  and  5  which permits the end cap  40  or  42  to be set into a secured or locked position. 
     When the end cap  40  or  42  is axially moved downward and placed on the implant body  20  base section  15  or  25 , a corresponding base tooth  30  will enter into the first interior space  62  of the variable aperture  61 . When the end cap  40  or  42  is axially seated on the exterior surface  16  of the implant base section  15  or  25 , the base extension  30  is located in the first interior space  62  of the variable aperture  61  and the aperture finger  65  is contacting and being urged or forced upward by the base section support surface  16 . The upward axial force provided by the base station support surface  16  provides an upward force Y, shown in  FIG. 8 , on the aperture finger tip  67 . The aperture finger  65  experiences this deflecting force because when the variable aperture  61  is in an equilibrium or static state, the finger tip  67  will extend downward below the plane (not shown) defined by the end cap seating surface  41 , as best shown in  FIG. 8 . Since the end cap seating surface  41  preferably must rests substantially flush or flat on the base section support surface  16  to permit subsequent rotation of the end cap  40  or  42  into a secured or locked position, the support surface  16  must push upwards on the aperture finger tip  67  and the aperture finger tip  67  must flex upward so that the seating surface  41  can appropriate seat substantially flush on the base section support  16 . The aperture finger  65 , and by extension the aperture finger tip  67 , will continue to axially flex or deflect so long as the deflecting force from the end cap  40  or  42  positioning continues. At the same time, as described previously, base extensions  30  have also entered into and are now positioned in corresponding wide sections  51  of the one or more end cap fixed apertures  45 . 
     In order to reach the end cap engaged or locking position, shown in  FIGS. 2 ,  4  and  5 , the end cap  40  or  42  is then rotated relative to the base section  15  or  25 , so that the base teeth or base extension  30  travel inside the variable aperture passage  61  substantially from a position at or near the first interior space  62  towards the variable aperture slot  63  and variable aperture stop wall  67  in the second interior space  64 . At the same time, the aperture finger  65  via the aperture finger tip  67 , which has been axially deflected upwards by the base section support surface  16 , slideably and rotationally travel along the periphery of the base section support surface  16  towards a corresponding base section securing depression  35  as the end cap  40  or  42  is rotationally moved to a secured or locking position. In the disclosed embodiment, the end cap  40  or  42  is rotated in a clockwise direction. As the end cap  40  or  42  is rotated and travels towards the engaged or locking position, the positioning tooth  30  travels inside the variable aperture  61  towards the variable aperture slot  63  and variable aperture stop wall  67  in the second interior space  64 , and the aperture finger tip  67  simultaneously slideably travels along the periphery of the base section support surface  16  towards a corresponding base section securing depression  35 . 
     As the positioning tooth  30  continues to travel inside from the first to second interior space  62  and  64 , the positioning tooth  30  encounters and abuts the variable aperture stop wall  69 . At the same time, when positioning tooth  30  abuts the variable aperture stop wall  69 , the aperture finger tip  67  will simultaneously encounter the securing depression entry or opening  37  which is appropriately positioned adjacent to the positioning tooth  30 , as shown in  FIG. 9 , and lies in the plane defined by the base section support surface  16 , as shown in  FIGS. 2 and 3 . At this point, the axial deflecting force, by the base section support surface  16 , that was axially and upwardly urging the aperture finger  65  in the direction Y, shown in  FIG. 8 , is removed. With the axial upward force on the aperture finger tip  67  now removed, the aperture finger&#39;s  65  resilient or spring-like properties will force or bias the aperture finger tip  67  back in an axial downward direction, opposite of the arrow Y. The aperture finger  65  now tends to axially deflect back to is equilibrium or static position, as shown in  FIGS. 3 and 8 . The aperture finger tip  67  thereby axially enters or snaps it the corresponding securing depression opening  37  as it tends back to its equilibrium or static position below the adjacent planes (not shown) defined by the end cap seating surface  41  and base section support surface  16 . The aperture finger tip  67  continues to axially deflect into the corresponding base section securing depression  35  until the aperture finger  65  reaches, abuts and sits substantially flush or flat with the base section support surface  16 . When the aperture finger  65  reaches the base section support surface  16 , any further aperture finger tip  67  deflection into the base section securing depression  35  will cease. The aperture finger tip  67  is now inside the corresponding base section securing depression  35 , as shown in  FIG. 2 , and has reached its final position. The final position of the aperture finger tip  67  in the secured or locking position may be the same or different position as the aperture finger tip&#39;s equilibrium or static position. The complementary and mechanical communication between the aperture finger  65 , aperture finger tip  67 , the base section securing depression  35 , the tooth head  29 , and the variable aperture stop wall  69  can comprise a second securing or locking mechanism  60 , shown in  FIGS. 2 and 4 . 
     At this point, the aperture finger  65  is in cooperative engagement with the base section securing depression  35 , and the variable aperture stop wall  69  is in cooperative engagement with the positioning tooth  30  will obstruct and prevent further rotational travel of the end cap  40  or  42  on the base section  15  or  25 . At this point the end cap  40  or  42  has reached the secured or locking position on the base section  15  or  25 . Simultaneously with this action, the positioning teeth  30  in the end cap fixed apertures  45  have also reached the secured or locking position on the base section  15  or  25  such that the end cap  40  or  42  is now securely positioned on the implant body  20 . 
     If an attempt is made to continue to move or force the end cap  40  or  42  to rotationally travel on the implant base section  15  or  25 , the variable aperture stop wall  67  and base section securing depression  35 , in combination with the fixed aperture stop walls  47  of the other end cap fixed apertures  45 , will prevent further travel of the positioning teeth  30  or aperture finger  65 , respectively. When at least one positioning or base tooth  30  reaches and abuts against a corresponding stop wall  47  or  67  or the aperture finger  65  enter or snaps into the base section securing depression  35 , the end cap  40  or  42  has reached the secured or locked position, shown in  FIGS. 2 ,  4  and  5 , on the implant body base section  15  or  25 . At this point, the end cap  40  or  42  is attached and secured to the implant body  20  in the secured or locked position. 
     In the locking position, shown in FIGS.  2  and  4 - 5 , the aperture finger  65  provides a holding force or friction force on base section securing depression  35  via contact between a finger tip curved underside  68  contacting the edge of the base section securing depression  35 . The locking or holding force provided by the finger tip curved underside  68  will tend to minimize or retard rotational movement by the end cap  40  or  42  in an unlocking direction due to the initial friction or inertia by the finger tip curved underside  68  against the edge of the base section securing depression  35 . The holding strength or force provided by the finger tip curved underside  68  may be augmented or controlled by selection and use of different materials with different resilient physical properties, or through the use of coating or adhesive substances between the finger tip curved underside  68  and the edge of the base section securing depression  35 . For example, a coating, such as silicone, or an adhesive such as epoxy, may be used to increase friction between the finger tip curved underside  68  and the edge of the base section securing depression  35 . Those of skill in the art will recognize that other substances or friction control mechanisms and material may be used to augment or control the holding force or strength and friction between the finger tip curved underside  68  and the edge of the base section securing depression  35 , such as roughened surfaces, dissimilar materials, and shape differences. 
     The end cap  40  or  42  will remain in the locked position until sufficient force is applied to overcome the holding force between finger tip curved underside  68  and the edge of the base section securing depression  35  and permit removal of the end cap  40  or  42 . In order to introduce such an unlocking force, the end cap  40  or  42  would be rotated in an opposite direction than was initially used to lock the end cap  40  or  42  onto the base section  15  or  25  as described above. In the embodiment shown in  FIG. 2-4 , the unlocking direction would be a counter clockwise direction. When the finger tip curved underside  68  of the aperture finger tip  67  encounters a an unlocking force sufficient to overcome its locking position and/or relative inertia at the locking position, the edge of the base section securing depression  35  will travel along the finger tip curved underside  68 . This mechanical travel in the unlocking rotational direction will cause the aperture finger tip  67  to move or deflect in an axial upward direction Y shown in  FIG. 8 . The finger tip curved underside  68  will permit the end cap  40  or  42  rotate in an unlocking direction while simultaneously resulting in the aperture finger  65  deflecting in an upward axial direction. This will continue until the aperture finger tip  67  reaches the corresponding securing depression opening  37 . At this point, the aperture finger tip  67  exits the base section securing depression  35  and begins to slideably travel on the base section support surface  16 , and will continue in this manner until the base tooth  30  reaches the first interior space  62  in the variable aperture  61 . At this point the end cap is in an unlocked position and can be axially removed from the base section  15  or  25 . 
     When such a removal force is introduced via opposite rotation of the end cap  40  or  42  relative to the base section  15  or  25 , the first and second securing or locking mechanism  50  and  60  will be simultaneously or complementarily released or disengaged. In the first securing or locking mechanism  50 , as the end cap  40  or  42  is rotated away from the locked position, the aperture protrusions  57  and fixed aperture stop walls  47  in the narrow sections  53  will move and travel away from the base teeth  30  and its undercut sections  31 . In this manner, the aperture protrusions  57  and undercut sections  31  will disengage. This will permit the base teeth  30  to move out of the narrow sections  53  and into the wide section  51  of the end cap&#39;s fixed apertures  45  thereby releasing the base teeth  30  from their locked positions. Simultaneously and complementarily, as discussed above relative to the second securing or locking mechanism  60 , the aperture finger  65  and aperture finger tip  67  will move and axially deflect upward and thereby permit the aperture finger  65  to slideably travel out of the base section securing depression  35  thereby releasing the aperture finger  65  from its locked position. The end cap  40  or  42  can then be axially removed away from the implant base section  15  or  25 . 
       FIGS. 2-9  show end caps  40  or  42  which have the same total number of end cap apertures  45  or  61  as corresponding base teeth  30  and base section securing depressions  35 . The disclosed embodiment includes six total aperture  45  and  61 , six corresponding base teeth or base extensions  30  and six adjacent corresponding base section securing depressions  35 . If the locking apertures or passages  45  and  61  are to axially accept entry of extending base teeth  30 , the end cap  40  must have at least the same number of locking apertures  45  and  61  as the number of extending base teeth  30 . If there are two extending base teeth, then the there must be at least two locking apertures  45  or  61 . If there are four extending base teeth  30 , then there must be at least four locking apertures or passages  45  or  61  in order that the end cap  40  or  42  can be axially inserted and seated onto the implant base section  15  or  25 . Those of skill in the art will recognize that other embodiments may include an end cap  40  or  42  having more apertures  45  or  61  than corresponding base teeth  30 . These embodiments would then include one or more empty end cap apertures  45  and  61 . Further, in other end cap aspects, the number of fixed apertures  45  could be the same as variable apertures  61 , or the number of fixed apertures could be less than the number of variable apertures. 
     In a preferred aspect, as best shown in  FIG. 9 , six securing depressions or indentations  35  are spaced at or about 60° apart from each other around the periphery of the implant base section  15  or  25  and adjacent to the corresponding six (6) base teeth  30 . There are preferably corresponding securing depressions or indentations  35  adjacent to each base section  30  so as to be able to accept and lockingly engage a corresponding securing finger  65  at a base tooth  30  location when the end cap  40  or  42  is securely positioned on the base section  15  or  25 . Having less securing depressions or indentations  35  than base teeth  30  will prevent locking engagement of the securing finger  65  at the tooth  30  position that do not have securing depressions or indentations  35 . As a result, in the disclosed aspect, there is preferably the same number of securing depressions or indentations  35  as base teeth  30 , and the securing depressions or indentations  35  are preferably adjacent to the base teeth  30  as best shown in  FIG. 9 . In other base section  15  embodiments which may include at least two or more than two base extensions  30 , the number of securing depressions or indentations  35  may be the same or different as the number of base extensions  30  and would preferably be adjacent to the base extensions, e.g., as shown in  FIG. 9 . 
     An additional advantageous aspect of the disclosed locking apertures or passages  45  and  61  is that they enable the end cap  40  or  42  to be selectively positioned or adjusted on the implant base section  15  or  25 . For example, during preassembly of the implant body  20  and end cap  45  and/or  61 . The end cap  40  or  42  can be adjustable relative to the implant body  20  and implant base section  15  or  25  about the longitudinal axis  5  of the implant body  20  to determine a selected axial delivery position or orientation. The number of locking apertures  45  and  61  determine the number of positions or rotational orientations at which the end cap  40  or  42  can be axially placed in or located on the implant base section  15  and  25 . The greater the number of locking apertures  45  and  61  the larger the number of positions or rotational positions the end cap  40  can be adjusted and axially placed in or located on the implant base section  15  and  25 . The more locking apertures or passages  45  and  61 , the greater degree of choice and control a surgeon will have in selecting a rotational position for the end cap  40  to be axially placed in or located on the implant base section  15  and  25 . This end cap aspect advantageously provides a surgeon selective control of where the end cap angulation θ and the end cap vertex height H will be positioned on the implant base section  15  or  25 . The ability to selectively position the end cap angulation θ permits a surgeon to determine where the end cap angulation θ and end cap height H will be applied or imparted to an the adjacent vertebral body  100  or  105 . Prior to insertion of the implant  10  into the intervertebral disc space  101 , the surgeon can decide where the end cap angulation θ and the end cap vertex height H are desired or needed for a particular medical procedure or clinical application. 
     As noted previously, a surgeon can selectively position the end cap  40  on the implant base plate  15  or  25  by rotating the end cap  40  relative to the base section  15  or  25 , either clockwise or counterclockwise, and then axially inserting the end cap locking apertures  45  and  61  onto the base teeth  30  at the desired or needed rotational position on the implant base plate  15 . This aspect enables selective positioning or orientation of the end cap angulation θ which in turn permits the surgeon to decide where the end cap angulation θ and end cap height H will be applied or imparted to an the adjacent vertebral body  100  or  105 . The clockwise or counterclockwise rotation of the end cap  40  or  42  moves or adjusts the end cap&#39;s  40  angulation θ and the end cap vertex height H relative to the implant base section  15  so as to position the end cap angulation θ and vertex height H at a desired or required point on the implant base section  15  or  25 . For example at anterior, antereolateral, posterior or lateral points about the vertebral member  100  or  105 , or vertebral disk space  101 . This is in turn will position the end cap angulation θ and vertex height H at a desired or required point relative to the adjacent intervetebral member  100  or  105  once the implant  10  is inserted and positioned within the intervertebral space  101 . The end cap  40  will then be able to impart desired or required angulation θ, orientation and vertex height H on the adjacent vertebral body at selected or required points on the adjacent vertebral body  100  or  105  to correct or improve the angulation, orientation, alignment and stabilization of the spine or spinal anatomy. 
     As noted above, the end cap  40  may be rotated so as to contact and impart angulation θ at different location points about the periphery of the adjacent vertebral body  100  or  105 . The number of locking aperture or passages  45  and  61  impact the incremental degree of control, through clockwise or counterclockwise end cap  40  rotation, that a surgeon will have in selecting the end cap angulation θ position between the implant  10  and the adjacent vertebral body  100  or  105 . In the embodiment shown in  FIGS. 2-7 , the end cap  40  has six locking apertures  45  and  61  which are evenly or equidistantly space in the area between the exterior contact surface  48  and seating surface  41 . The equidistant spacing results in the locking apertures  45  and  61  being located and spaced apart from each other at about sixty degrees (60°) around the end cap  40 . In this embodiment then, the end cap  40  can be rotationally advanced, clockwise or counterclockwise, in single or multiple increments of sixty degrees (60°) in order to rotationally position or reposition the end cap angulation θ position between the implant  10  and the adjacent vertebral body  100  or  105 . 
     A greater degree of control in rotationally and incrementally advancing the end cap  40 , about the implant base section  15 , may be obtained by increasing the number of locking apertures or passages  45  and  61 . For example, if the end cap  40  were to have eight (8) locking apertures or passages  45  and  61  evenly or equidistantly spaced in the area between the contact surface  48  and seating surface  41 . Then, equidistant circular spacing would result in the locking apertures or passages  45  and  61  being located and spaced apart from each other at forty-five degrees (45°) around the substantially circular area between the contact surface  48  and seating surface  41  of the end cap  40 . In this case, the end cap  40  can be rotationally advanced, clockwise or counterclockwise, in single or multiple increments of forty-five degrees (45°) in order to position or reposition the end cap angulation θ position between the implant  10  and the adjacent vertebral body  100  or  105 . The larger number of locking apertures or passages  45  provides a surgeon the ability to rotationally position or reposition the end cap  40  in smaller discrete increments. This greater degree of control provides the surgeon with more precise control on where the end cap angulation θ will be positioned between the implant  10  and the adjacent vertebral body  100  or  105 . In this manner, the selected angulation θ and end cap vertex height H can be imparted to an adjacent vertebral member  100  or  105  to thereby impart or drive angular orientation and height adjustment of the adjacent vertebral member  100  or  105  for correction or improved alignment, angulation, orientation, and stabilization of the spine or spinal anatomy. 
     In one aspect, assembling the implant  10  includes initially determining the type of end cap  40  or  42  that is to be attached to the body  20 . The end cap  40  or  42  may be selected based on the size of the intervertebral space  101  and the anatomy of the vertebral members  100  and  105 . The appropriate or desired axial approach position of the end cap  40  or  42  is then selected by a surgeon so that the end cap  40  or  42  can be axially placed on the on the implant base plate  15  or  25 . 
     The proper end cap  40  or  42  and desired axial approach are determined, and the end cap  40  or  42  is axially placed on the base section  15  or  25  of the implant body  20 . The one or more end cap fixed apertures  45  are aligned with the one or more corresponding base teeth or base extensions  30  that axially extend outward from the base section support surface  16  of the implant body  20 . The end cap  40  or  42  is axially moved towards the implant body  20  with the base teeth  30  to insert the base teeth  30  into the wide sections  438  of the fixed apertures  45 . The end cap  40  or  42  is moved towards the implant body  20  until the end cap seating surface  41  contacts against the base section support surface  16  of the implant body  20 . 
     Once the end cap  40  or  42  is axially mounted onto the one or more base teeth or base extensions  30  via the corresponding wide section  51  of the one or more end cap apertures  45 , the end cap  40  or  42  is rotated relative to the implant body  20  base section  15  or  25 . In the embodiment illustrated in  FIGS. 2-5 , the end cap  30  is rotated in a clockwise direction. This rotation moves the base teeth  30  into the narrow sections  53  of the end cap apertures  45 . This movement causes the aperture protrusions  57 , that extend into the end cap apertures  45 , to be moved underneath the base teeth heads  29  and into the base teeth undercut sections  31 . The end cap  40  or  42  may be rotated until the base teeth heads  29  contact against the fixed apertures stop walls  47  and/or just until the aperture protrusions  57  move underneath the heads  29  and into the undercut sections  31 . 
     In one aspect, the base teeth or base extensions  30  on the implant body  20  and the end cap apertures  45  each have complementary and cooperating size and shape. As a result, rotation of the end cap  40  or  42  causes each of the plurality of end cap fixed aperture  45  to be secured around a corresponding base tooth or base extension  30  in a similar manner. In other aspects, one or more of the base teeth or base extensions  30  and/or fixed end cap apertures  45  may have different shapes and/or sizes. This may cause differing amounts of contact between the various base teeth or base extensions  30  and end cap apertures  45 , however, the base teeth  30  and corresponding end cap apertures  45  would have complementary and cooperating shapes and/or sizes such that they permit rotation of the end cap  40  or  42  so that each end cap apertures  45  can at least be partially secured to corresponding base teeth  30 . 
     As the base teeth  30  and corresponding end cap fixed apertures  45  are being secured to each other when the end cap  40  or  42  is positioned on the base sections  15  or  25 , the end cap variable aperture  61  simultaneously aligns and is axially placed on a corresponding implant base tooth  30 . The position of the base tooth  30  is arranged such that the variable aperture  61  aligns with a corresponding base tooth  30  when end cap  40  or  42  is axially positioned on the base section support surface  16  of the implant body  20 . As discussed above, when the end cap  40  or  42  is fully seated on the exterior surface  16  of the base section  15  or  25 , the base tooth  30  is located in the first interior space  62 , and the aperture finger  65  rests on and has been axially and upwardly deflected by the base section support surface  16 . The base extensions  30  have also entered into and are now positioned in corresponding wide sections  51  of the one or more end cap fixed apertures  45 . As the end cap  40  or  42  is rotated relative to the implant body  20  base section  15  or  25 , the positioning tooth  30  travels inside the variable aperture  61  from the first interior space  62  towards the variable aperture stop wall  69  in the second interior space  64 . At the same time, the aperture finger tip  67  travels on the base section surface  16  and axially enters or snaps in to a corresponding securing depressions  35  when the aperture finger tip  67  encounters a corresponding securing depression opening  37 . 
     Once the positioning tooth  30  travels into the second interior space  64 , the positioning tooth  30  will reach and abut up against the variable aperture stop wall  69  and the aperture finger tip  67  enters or snaps in to a corresponding securing depression  35  which will prevent further travel of the positioning tooth  30  inside the variable aperture  61 , as best shown in  FIGS. 2 and 4 . The plurality of base teeth  30  traveling in the other end cap fixed apertures  45  will simultaneously reach their corresponding fixed aperture stop walls  47  thereby also preventing further travel of the positioning teeth  30  in the other end cap fixed apertures  45 . When at least one positioning or base tooth  30  reaches and abuts against a corresponding stop wall  47  or  69 , the end cap  40  or  42  has reached the locking position on the implant base section  15  or  25 , as best shown in  FIGS. 2 and 4 . At this point, the end cap  40  or  42  is attached and secured to the implant body  20  base section  15  or  25  in an engaged or locked position. 
     The implants  10  and end caps  40 ,  42  may be implanted within a living patient for the treatment of various spinal disorders. The implants  10  and end caps  40 ,  42  may also be implanted in a non-living situation, such as within a cadaver, model, and the like. The non-living situation may be for one or more of testing, training, and demonstration purposes. 
     The end caps disclosed in this disclosure are preferably comprised of biocompatible materials substrates which can be used in combination with implants or devices configured to be inserted into an intervertebral space and contact against adjacent vertebral members. The biocompatible material substrate may include, among others, polyetheretherketone (PEEK) polymer material, homopolymers, co-polymers and oligomers of polyhydroxy acids, polyesters, polyorthoesters, polyanhydrides, polydioxanone, polydioxanediones, polyesteramides, polyaminoacids, polyamides, polycarbonates, polylactide, polyglycolide, tyrosine-derived polycarbonate, polyanhydride, polyorthoester, polyphosphazene, polyethylene, polyester, polyvinyl alcohol, polyacrylonitrile, polyamide, polytetrafluorethylene, poly-paraphenylene terephthalamide, polyetherketoneketone (PEKK); polyaryletherketones (PAEK), cellulose, carbon fiber reinforced composite, and mixtures thereof. The biocompatible material substrate may also be a metallic material and may include, among others, stainless steel, titanium, nitinol, platinum, tungsten, silver, palladium, cobalt chrome alloys, shape memory nitinol and mixtures thereof. The biocompatible material used can depend on the patient&#39;s need and physician requirements. 
     Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper”, and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc and are also not intended to be limiting. Like terms refer to like elements throughout the description. 
     As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise. 
     While embodiments of the invention have been illustrated and described in the present disclosure, the disclosure is to be considered as illustrative and not restrictive in character. The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.