Patent Application
20120029640
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.
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.
The present application is directed to intervertebral implants for spacing apart vertebral members 100 and 105.
As shown in
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.
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.
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
The implant base section's 15 and 25 central base aperture 17, shown in
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
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.
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
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
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
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
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.
As best shown in
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'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
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
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
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
In order to reach the end cap engaged or locking position, shown in
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
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
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
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'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.
In a preferred aspect, as best shown in
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'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
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
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
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'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.
