Patent Application
20120197398
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 imparts an end cap angulation to an adjacent vertebral body at a selected point when the implant is positioned in the intervertebral space. The implant comprises an implant body comprising a base section having a plurality of base extensions, and an end cap adapted for selective positioning at a selected point on the base section. The end cap further comprises an exterior contact surface that faces away from the implant body when the end cap is positioned on the base section, a seating surface adapted to contact the base section when the end cap is positioned on the implant body, an end cap angulation, a locking aperture adapted to receive and engage a corresponding base extension, a flexing aperture adapted to receive a base extension, and a variable slot aperture adapted to receive a base extension. The variable slot aperture and flexible aperture cooperate to enable the end cap to resiliently contract as the end cap is positioned on the base section. Further, the flexing and variable slot apertures have an opposing end cap orientation which enables a resilient end cap aspect that facilitates axial positioning and removal of the end cap. The locking apertures are configured to engage corresponding base extensions, and the flexible aperture and variable slot apertures are configured to receive corresponding base extensions when the end cap is positioned on the base section. The locking aperture, flexible aperture and variable slot apertures are configured to simultaneously receive corresponding base extensions to thereby securely maintain the end cap positioned on the base section. The flexible aperture can be adapted to prevent rotational movement of the end cap relative to the implant base section. The end cap angulation comprises an angular value in the range of between zero degrees to fifteen degrees (0°-15°).
The present application also discloses an end cap for use with an implant having a base section with at a plurality of base extensions. The end cap is axially placed on the base section and positioned or moved into a secure or locked position on the base section. The end cap imparts an end cap angulation to an adjacent vertebral body at a selected point when the implant is positioned in an intervertebral space. The end cap comprises an exterior contact surface; a seating surface; a substantially vertical exterior cap wall extending between the exterior contact surface and the seating surface; at least two locking apertures extending between the exterior contact surface and the seating surface and adapted to receive and engage corresponding base extensions; a flexing aperture extending between the exterior contact surface and the seating surface and adapted to receive a base extension; and a variable slot aperture extending between the exterior contact surface and the seating surface and adapted to receive a base extension. The variable slot aperture is also adapted to enable the end cap to contract as it is positioned on the base section. The flexing and variable slot apertures preferably have an opposing end cap orientation which enables a resilient end cap aspect that facilitates axial positioning and removal of the end cap relative to the implant base section. Further, the locking apertures are configured to engage corresponding base extensions, and the flexing aperture and variable slot aperture are configured receive corresponding base extensions when the end cap is positioned on the base section. The locking aperture, flexible aperture and variable slot apertures are configured to simultaneously receive corresponding base extensions to thereby securely maintain the end cap positioned on the base section. The flexible aperture and/or the locking aperture are adapted to prevent rotational movement of the end cap relative to the implant base section. The end cap angulation comprises an angular value in the range of between zero degrees to fifteen degrees (0°-15°).
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 inner implant body 22 includes a first base section 15 and the outer implant body 24 includes a hollow interior and a second base section 25. 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 base extensions 30. In such a case, there must be at least the same number of locking, variable slot and flexing apertures or passages 55, 65 and 75 to accept the base extensions 30. There could also be more locking, variable slot or flexing apertures or passages 55, 65 and 75 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, variable slot and flexing apertures or passages 55, 65 and 75 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, variable slot and flexing apertures 55, 65 and 75 are preferably 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. The implant base section's 15 and 25 central base aperture 17, shown in
In the aspect shown in
The end cap 40 or 42, via its end cap locking, variable slot and flexing apertures or passages 55, 65 and 75, can be attached to the implant body 20 via the base teeth or base extensions 30 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 and engagement 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 assist in the prevention of 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 is 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
In one aspect, shown in
The locking aperture or passage 55 is preferably sufficiently sized and configured to permit the base tooth head 29 to enter the end cap's locking aperture 55 as the end cap 40 or 42 is axially mounted onto the implant body 20. The locking aperture protrusion 57 is located adjacent the seating surface 41 and extends away from the interior curved wall 53. This positioning locates the locking aperture protrusion 57 such that it can fit under the tooth head's 29 underside of the base tooth or base extension 30 and within the interior undercut section 31 when the end cap 40 or 42 is axially positioned and secured to the implant body 20, as best shown in
The locking protrusion or projections 57 interact and cooperatively engage with the base tooth head 29 to enable the end cap 40 or 42 to be axially mounted and locked onto the implant body 20. The locking protrusions or projections 57 in cooperation and interaction with the base tooth head's 29 underside and interior undercut section 31 permit the end cap 40 or 42 to be axially positioned and locked or secured to the implant body base sections 15 or 25. The locking aperture protrusions 57 are configured to fit within the interior undercut section 31 and axially interfere with the underside of the tooth head 29 to enable axially attachment of the end cap 40 or 42 to the implant body 20 base section 15 or 25.
When the end cap 40 or 42 is axially positioned on the base section 15 or 30, a base extension 30, via the tooth head 29, will interact with a corresponding locking aperture protrusion 57 as the base extension 30 enters the locking aperture 55. As the end cap 40 or 42 axially travels toward the fully seated position on the implant body base sections 15 or 25, the end cap 40 or 42 contracts via simultaneous cooperating flexing action from the variable slot aperture 65 and flexing aperture 75 (discussed below). This end cap's 40 or 42 contraction permits the locking aperture protrusion 57 to slideably travel along the interior topside of the tooth head 29 towards the implant base section 15 or 25 and a secured or locking position. When the locking aperture protrusion 57 travels past the edge of the tooth head 29 the end cap 40 or 42 expands via the opposite flexing action of the variable slot aperture 65 and flexing aperture 75. This end cap's 40 or 42 expansion permits the locking aperture protrusion 57 to move outwardly and towards a secured or locking position under the tooth head 29 of the base tooth or base extension 30 and within the interior undercut section 31, as best shown in
Once the end cap 40 or 42 is seated in the locking aperture 55, the combined locking aperture protrusions 57 and underside of the teeth heads 29 will obstruct and prevent axial travel or movement of the locked end cap 40 or 42 away from the implant body base sections 15 or 25. Additionally, the locking aperture 55, via its sidewalls 51 and 52, in combination and cooperation with corresponding base teeth 30 therein will simultaneously interact to obstruct and prevent rotational travel or movement of the locked end cap 40 or 42 once in a secured or locked position on the implant body base sections 15 or 25. At this point, the locking aperture protrusion 57 is in complementary and mechanical communication with the underside of the base tooth 29 and the interior undercut section 31 of the base tooth or base extension 30 and in an axially obstructive fit with underside of the base tooth 29 which locks or secures the positioning tooth 30 inside the locking aperture 55. If an attempt is made to axially remove or impart axial travel on the end cap 40 or 42, the locking aperture protrusion 57 will abut up against the underside of the tooth head 29 and prevent axial travel of the end cap 40 or 41 away from the implant body base sections 15 or 25. Further, if an attempt is made to rotationally move or force the end cap 40 or 42 to rotationally travel on the implant base section 15 or 25, the locking aperture 55 sidewalls 51 and 52 will prevent rotational movement or travel of the end cap 40 or 42 relative to the positioning teeth 30, as best shown in
The end cap 40 or 42 is now in a secured or locked position, 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 locking aperture protrusion 57, the underside of the tooth head 29 and the interior undercut section 31 are preferably and complementarily configured such that, at the engaged and locked position, e.g., as shown in
The holding strength of the locking mechanism 50 between the positioning teeth 30 and fixed locking aperture 55, via the locking aperture protrusion 57, underside of the base tooth head 29, and the interior undercut section 31, may be augmented or controlled by the addition or use of a coating or adhesive substance between the locking aperture protrusion 57, the base tooth head underside and the interior 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, the base tooth head underside and the interior 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 the holding strength between the fixed locking aperture 55 and the positioning teeth 30, such as roughened surfaces, dissimilar materials, and shape differences.
The complementary and mechanical communication between the locking aperture protrusion 57, the base tooth head underside and the interior 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 locking 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 locking aperture protrusions 57 abutting the underside of the teeth heads in the interior undercut sections 31. The tooth head 29 prevents 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. Also, once in a locked position, the locking and flexing apertures 55 and 75 simultaneously prevent rotational movement of the end cap 40 or 42 relative to the implant base section 15 or 25. This is accomplished via the locking and flexing apertures' 55 and 75 sidewalls 51, 52, 71, and 72 into which corresponding base teeth 30 will abut into if rotational movement or travel is attempted once in the locked position, as best shown in
The variable slot aperture 65 comprises a slot 63 that is adapted to receive a corresponding base tooth or base extension 30 extending from the implant body 20 base sections 15 or 25. The variable slot aperture 65 further comprises a pair of substantially parallel sidewalls 61 and 62 which define the variable slot 63. The pair of substantially parallel sidewalls 61 and 62 are separated by the variable slot 63. The variable slot aperture 65 is preferably configured and sized, via the side walls 61 and 62 and variable slot 63, such that the end cap 40 or 42 can sufficiently contract or expand necessary to permit the end cap 40 or 42 to be moved into or out of a locked position relative to the implant base section 15 or 25. As a result of the variable slot aperture's 65 preferred configuration and size, there is sufficient play in the variable slot 63 between a corresponding base tooth 30 and the variable slot aperture side walls 61 and 62 such that the end cap 40 or 42 can contract or expand, which thereby makes the slot contract or expand, to permit the end cap 40 or 42 to be moved into or out of a locked position on the base section 15 or 25. The opposing flexing aperture or passage 75 preferably comprises a pair of sidewalls 71 and 72 bounded by an interior curved wall 73 and an opposing exterior open space 74. The variable slot aperture 65 and flexing aperture 75 are configured and adapted to receive corresponding base extensions and corresponding base teeth heads 29 to enable the end cap 40 or 42 to be axially mounted and positioned onto the implant body 20 the base section. In the embodiment disclosed, the variable slot aperture 65 and flexing aperture 75 are adapted to simultaneously operate to enable the end cap to contract or expand as may be needed to move the end cap 40 or 42 into or out of a locked position relative to the implant base section 15 or 25. Further, once the end cap 40 or 42 are in a locked position, the flexing aperture 75, via its side walls 71 and 72, may be adapted and configured to prevent rotational movement of the end cap 40 or 42 relative to the implant base section 15 or 25.
In a preferred embodiment, the end cap 40 or 42 comprises one (1) variable slot aperture 65 and one flexing aperture 75. The variable slot aperture 65 and flexing aperture 75 are preferably oriented as opposing apertures on the end cap 40 or 42, best shown in
The variable slot aperture 65 and one flexing aperture 75, as discussed, enable the end cap 40 or 42 to contract or expand as needed to permit the end cap 40 or 42 to be moved into or out of a locked position relative to the implant base section 15 or 25. In a preferred aspect, the end cap 40 or 42 will preferably comprise a single variable slot aperture 65 and a single flexing aperture 75. The end cap 40 or 42 will preferably comprise a variable slot aperture 65 and flexing aperture 75 in an opposing orientation on the end cap 40 or 42. In this manner, the variable slot aperture 65 and flexing aperture 75 can compliment each other and cooperate to enable the end cap 40 or 42 to contract or expand as needed to move the end cap 40 or 42 into or out of a locked position relative to the implant base section 15 or 25. Those of skill in the art will recognize that the specific combination of locking apertures 55, variable slot apertures 65 and/or flexing apertures 75 use in an end cap 40 or 42 may be different than the disclosed embodiment, and will depend on the needs or selection of a surgeon, medical procedure or clinical application. Further, the locking apertures 55, variable slot aperture 65 and flexing aperture 75 may have the same or different shape, configuration and/or sizes so long as they are configured to accept corresponding base teeth 30 and enable the end cap 40 or 42 to contract or expand as needed to move the end cap 40 or 42 into or out of a locked position relative to the implant base section 15 or 25.
The variable slot aperture or passage 65 is preferably sufficiently sized and configured to permit the base tooth head 29 to enter the end cap's variable slot aperture 65 as the end cap 40 or 42 is axially mounted or positioned onto the implant body 20 base section 15 or 25. The opposing complimentary flexing aperture or passage 75 is also sized and configured to permit the base tooth head 29 to enter the flexing aperture or passage 75 between the sidewalls 71 and 72, as the end cap 40 or 42 is axially mounted or positioned onto the implant body 20 base section 15 or 25. In a preferred aspect, the variable slot and flexing apertures 65 and 75 will simultaneously and complimentarily cooperate, in combination with the locking apertures 55, to permit the end cap 40 or 42 to be attached and secured to the implant body 20 when the end cap 40 or 42 is axially placed on the base teeth 30 of the implant body base sections 15 or 25.
When the end cap 40 or 42 is axially positioned on the base section 15 or 30, corresponding base extensions or teeth 30, via the tooth heads 29, will simultaneously enter the variable slot and flexing apertures or passages 65 and 75. As the end cap 40 or 42 axially travels to the fully seated and locked position in the locking apertures 55, the implant base teeth 30 fully enter and are positioned in the variable slot and flexing apertures or passages 65 and 75 between the respective sidewalls 61, 62, 71 and 72 when the end cap 40 or 42 reaches a secured or locking position on the implant base section 15 or 25. The mechanical communication between the teeth heads 29 and the respective locking aperture 55 and flexing aperture 75 side walls 51, 52, 71, and 72 rotational lock the end cap 40 or 42 and can comprise a second securing mechanism 60, as shown in
The end cap's locking apertures 55, and variable slot and flexing apertures 65 and 75 simultaneously cooperate to permit end cap 40 or 42 placement onto the implant base section 15 or 25. As discussed previously, the variable slot aperture 65 and complementary flexible aperture 76 aspects and characteristics enable contraction of the end cap 40 or 42 which will thereby contract or reduce the variable aperture slot 63. Once in a contracted position, the end cap 40 or 42 can be axially positioned on the base section 15 or 30. As the end cap 40 or 42 is axially positioned on implant base section 15 or 25, corresponding base extensions 30, via the inclined tooth heads 29, will interact with the locking aperture protrusions 57 as the base extensions 30 enters the locking apertures 55. As the end cap 40 or 42 axially travels towards the fully seated position in the locking apertures 55, the locking aperture protrusions 57 slideably travel along the interior topside of the inclined tooth head 29 towards the implant base section 15 or 25 and a secured or locking position. The result of the axial movement of the end cap 40 or 42 towards the implant base section 15 or 25 is that an opposing upward and inward force is imparted by the base teeth 30, via the teeth heads 29, to the end cap 4042 which tends to further contract end cap and reduce the variable apertures slot 63.
As the end cap 40 or 42 continues to be axially moved towards the implant base section 15 or 25, and as it continues to experience the opposing base teeth force, the end cap's 40 or 42 physical composition and resilient or spring-like properties and variable aperture slot 63 enable the end cap 40 or 42 to further contract, deflect or flex in a manner that tends to decrease or reduce the variable aperture slot 63 size or the distance between the side walls 61 and 62. The material or composition make up of the end cap 40 or 42, and the relative position and configurations of the variable slot aperture 65 and aperture slot 63 provide the end cap 40 or 42 with physical characteristics and properties such that in a preferred aspect, the end cap 40 or 42 is resilient, spring-like, and flexible during axial positioning of the end cap 40 or 42 onto the implant base section 15 or 25.
As the end cap 40 or 42 continues to contract, the variable aperture slot 63 continues to decrease or diminish which in turn permits the end cap 40 or 42 to continue axial movement towards the implant base section 15 or 25. Continued end cap 40 or 42 axial movement towards the implant base section 15 or 25 permits continued simultaneous sliding travel of the locking aperture protrusions 57 along the interior topside of corresponding inclined teeth heads 29 towards a secured or locking position. When the locking aperture protrusions 57 travel past the edge of a corresponding teeth heads 29, the end cap 40 or 42 and the variable aperture slot 63 will cease contracting. This is the case since the opposing inward force imparted on the end cap 40 or 42 by the base teeth 30 via the inclined tooth head 29 is no longer present. With the opposing inward force imparted on the end cap 40 or 42 by the corresponding teeth heads 29 now removed, and with continued axial end cap 40 or 42 movement towards the implant base section 15 or 25, the end cap's 40 or 42 resilient or spring-like properties will force or bias the end cap 40 or 42 outwardly in an expanding direction tending to make the end cap 40 or 42 and variable aperture slot 63 larger. The end cap 40 or 42 will tend to deflect or expand back to an equilibrium or static position, for example as shown in
At this point, the end cap 40 or 42 and variable aperture slot 63 begin to expand as the end cap 40 or 42 continues axial movement towards the implant base section 15 or 25. The locking aperture protrusions 57 will then begin to radially move outward towards a secured or locking position under the corresponding base tooth head 29 and within the interior undercut base teeth section 31, as best shown in
Once in the secure or locked position, the locking apertures 55 are in complementary and mechanical communication with the underside of the corresponding base tooth 29 and interior undercut sections 31 of the base teeth 30 and in an axially obstructive fit with the base teeth interior undersides. Once the end cap 40 or 42 is seated in the locking aperture 55, the interior undersides of the teeth heads 29 will obstruct and prevent axial travel or movement of the positioning teeth 30 inside the locking aperture 55. If an attempt is made to axially remove or impart axial travel on the end cap 40 or 42 so as to unlock the end cap 40 or 42, the locking aperture protrusions 57 will abut up against the underside of corresponding tooth heads 29 which will prevent axial travel of the end cap 40 or 41. Also, if an attempt is made to rotationally move or force the end cap 40 or 42 to rotationally travel on the implant base section 15 or 25, the respective side walls 51, 52, 71 and 72 of the locking aperture 55 and flexing aperture 75 will prevent rotational movement or travel of the end cap 40 or 42 relative to the positioning teeth 30, as best shown in
Once the end cap 40 or 42 is in the secure or locked position on the implant base section 15 or 25, the locking aperture and flexing apertures' 55 and 75 respective sidewalls 61, 62, 71 and 72 will obstruct and prevent rotational travel or movement of the end cap 40 or 42 relative to the positioning tooth 30 which is now inside the locking and flexible apertures 55 and 75. If an attempt is made to rotationally move or force the end cap 40 or 42 to rotationally travel on the implant base section 15 or 25, the respective locking aperture 55 and flexing aperture's 75 side walls 51, 52, 71 and 72 will prevent rotational movement or travel of the end cap 40 or 42 relative to the positioning teeth 30, as best shown in
The end cap 40 or 42 will remain in the locked position until sufficient force is applied to contract the end cap 40 or 42 to unlock or disengage the locking aperture protrusions 57 from corresponding undersides of the teeth heads 29 and interior undercut sections 31. When such a disengagement or removal force is introduced to the end cap 40 or 42, the locking aperture protrusions 57 will disengage corresponding base teeth 30 to simultaneously release or disengage the securing or locking mechanism 50. At the disengagement or unlocking point, the locking aperture protrusions 57 are outside the undersides of the teeth heads 29 and interior undercut sections 31. The underside of the teeth heads 29 then, no longer prevent or interferes with axial movement or removal of the locking aperture protrusion 57 away from the base teeth 30, and thereby axial movement of the end cap 40 or 42 away from the positioning teeth 30 and base section 15 and 25 is possible at the disengagement point. The end cap 40 or 42 can then be axially moved away from the base teeth 30 and implant base section 15 or 25. The removal, unlocking or disengagement force may be applied manually by a surgeon with the use and assistance of instruments (not shown).
An additional advantageous aspect of the disclosed end cap apertures or passages 55, 65 and 75 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 40 or 42, 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 end cap apertures 55, 65 and 75 determines 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 end cap apertures 55, 65 and 75, 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 end cap apertures or passages 55, 65 and 75, 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 and positioning apertures 55, 65 and 75 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 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 and positioning apertures or passages 55, 65 and 75 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 or 42, about the implant base section 15, may be obtained by increasing the number of locking, variable slot and flexible apertures or passages 55, 65 and 75. For example, if the end cap 40 were to have eight (8) locking, variable slot and flexible apertures or passages 55, 65 and 75 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, variable slot and flexible apertures or passages 55, 65 and 75 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 or 42. 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, variable slot and flexible apertures or passages 55, 65, and 65 provides a surgeon the ability to rotationally position or reposition the end cap 40 or 42 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 apertures or passages 55, 65 and 75 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 end cap apertures 55, 65 and 75. As the end cap 40 or 42 is axially positioned on the base section 15 or 30, corresponding base extensions 30, via the teeth heads 29 and interior undercut tooth sections 31, will interact with the locking aperture protrusions 57 as the base extensions 30 enter the locking apertures 55. Simultaneously, corresponding base extensions 30, via corresponding teeth heads 29, will enter the variable slot and flexible apertures 65 and 75 as the end cap 40 or 42 is axially moved towards the implant body 20.
As the end cap 40 or 42 continues to axially travel towards a locking position on the base section 15 or 25 of the implant body 20, the locking aperture protrusions 57 slideably travel along the interior topside of a respective inclined tooth head 29 towards the implant base section 15 or 25 and a secured or locking position. As the end cap 40 or 42 continues to axially move towards the implant base section 15 or 25, it experiences an opposing base tooth force which forces the end cap 40 or 42 to contract and deflect such that the variable aperture slot 63 contracts or is reduced. As the end cap 40 or 42 continues its axial travel, the aperture slot 63 continues to contract which in turn permits the end cap 40 or 42 to continue to travel on the inclined tooth head towards the implant base section 15 or 25. When the locking aperture protrusions 57 travel past the interior edge of the corresponding tooth heads 29, the end cap 40 or 42 and the variable aperture slot 63 will cease contracting since the opposing tooth force, imparted on the end cap 40 or 42 base by the tooth head 29, is no longer present.
With the opposing tooth head force now removed, the end cap's 40 or 42 resilient or spring-like properties will deflect or bias the end cap 40 or 42 back in an expanding direction tending to make the aperture slot 63 larger. The end cap's 40 or 42 and variable aperture slot's 63 expansion will permit the end cap 40 or 42 to continue axially movement towards the implant base section 15 or 25. The end cap 40 or 42 will deflect back towards an equilibrium or static position, as shown in
Once in the engaged or locked position, 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.
