Retention assemblies for intervertebral devices
Consistent with the present disclosure, retention assemblies for maintaining the relative position of adjacent vertebral bodies and an implantable device positioned therebetween are described herein. Such retention assemblies may include a plate body and a coupler. The plate body may include structures to allow fixedly attaching the retention assembly to adjacent intervertebral bodies, using vertebral body screws or the like, for example. Furthermore, the coupler may include expandable structures to engage a portion of an implantable device to fixedly attach the retention assembly to the implantable device. Accordingly, once the retention assembly is deployed, the implantable device is fixedly held in relation to the adjacent vertebral bodies, decreasing post operative movement of the implantable device relative to the adjacent vertebral bodies.
1 . An intervertebral device ( 100 ) comprising:
a base element ( 110 ), the base element ( 110 ) including a proximal end ( 112 ) and a distal end ( 130 ), a first side ( 122 ), a second side ( 124 ), a bottom surface ( 136 ), and a top surface, the base ( 110 ) including a distal opening ( 116 ) for attachment of a plate assembly ( 300 ) so that the plate assembly is oriented orthogonally with respect to a longitudinal axis of the base element,
the plate assembly ( 300 ) having a coupler ( 400 ), which provides an interface between the plate assembly ( 300 ) and the base element ( 110 ) of the intervertebral device ( 100 ), the coupler ( 400 ) includes an inner housing ( 410 ) sized to fit within the distal opening ( 116 ), the inner housing ( 410 ) having a first lumen ( 410 L 1 ) extending therethrough, a second lumen ( 41012 ), which is oriented substantially perpendicular to the first lumen ( 410 L 1 ), and positioned to intersect with the first lumen,
one or more protrusion members ( 430 ) being positioned within the second lumen and constructed to translate within the second lumen ( 410 L 2 ),
an elongate member ( 420 ) constructed and arranged to translate through the first lumen ( 41011 ) to interact with the one or more protrusion members ( 430 ), wherein moving the elongate member in a first direction causes translation of the one or more protrusion members, causing the one or more protrusion members to extend beyond an outer perimeter of the inner housing ( 410 ) to engage the base element ( 110 ).
2 . The intervertebral device of claim 1 wherein the distal opening ( 116 ) includes a circumferential groove ( 118 ) on an inner surface thereof positioned to cooperate with the one or more protrusion members ( 430 ) in the extended position.
3 . The intervertebral device of claim 2 wherein the circumferential groove ( 118 ) and the one or more protrusion members ( 430 ) cooperate to allow for angular attachment between the base element ( 110 ) and the plate assembly ( 300 ).
4 . The intervertebral device ( 100 ) of claim 3 wherein the plate assembly ( 300 ) is secured to the base element ( 110 ) to allow for polyaxial alignment between the base element and the plate assembly ( 300 ).
5 . The intervertebral device ( 100 ) of claim 4 wherein the plate assembly ( 300 ) can be fixedly secured to the base element ( 110 ), allowing for the polyaxial alignment between the base element and the plate assembly ( 300 ).
6 . The intervertebral device ( 100 ) of claim 1 wherein the elongate member ( 420 ) is threaded, the first lumen ( 410 L 1 ) having internal threads to cooperate with the elongate member to allow the elongate member to be rotated clockwise and anti-clockwise to provide controlled inward and outward traversal of the elongate member.
7 . The intervertebral device ( 100 ) of claim 6 wherein the elongate member ( 420 ) includes a cap ( 625 A) secured to the elongate member to allow rotation of the elongate member without rotation of the cap ( 625 A).
8 . The intervertebral device ( 100 ) of claim 7 wherein the cap ( 625 A) includes a transition surface ( 626 A) which cooperates with the one or more protrusion members ( 430 ) to cause the one or more protrusion members ( 430 ) to translate within the second lumen ( 410 L 2 ).
9 . The intervertebral device ( 100 ) of claim 8 wherein the transition surface ( 626 A) is conical in shape.
10 . The intervertebral device ( 100 ) of claim 8 wherein the protrusion ( 430 ) includes a first side surface ( 430 C 1 ), a second side surface ( 430 C 2 ), a third side surface ( 430 C 3 ), a fourth side surface ( 43004 ), a bottom surface ( 430 B), and a top surface ( 430 T).
11 . The intervertebral device ( 100 ) of claim 10 wherein the top surface ( 430 T) further includes a flat top surface ( 434 ) formed by the relative separation of a first sloped surface ( 436 A) and a second sloped surface ( 436 B).
12 . The intervertebral device ( 100 ) of claim 10 wherein the protrusion ( 430 ) includes tabs ( 438 ) which maintain a desired orientation of the protrusion ( 430 ) with respect to the housing ( 410 ) as the protrusion ( 430 ) translates along the lumen ( 410 L 2 ) of the housing ( 410 ), the lumen ( 410 L 2 ) having corresponding flat surfaces ( 430 C 2 ) ( 430 C 4 ) respectively to cooperate with the tabs ( 438 ).
13 . The intervertebral device ( 100 ) of claim 1 including a plate cap ( 440 ) positioned to circumscribe the inner housing ( 410 ).
14 . The intervertebral device ( 100 ) of claim 13 wherein the plate cap ( 440 ) includes a keyed outer shape constructed to cooperate with aperture ( 340 ) of the plate assembly ( 300 ) to key the plate cap ( 440 ) to the coupler ( 400 ), requiring them to move together.
15 . The intervertebral device ( 100 ) of claim 1 wherein the coupler ( 400 ) further includes a plate cap ( 440 ) adapted to be slidably coupled to the housing ( 410 ), the plate cap ( 440 ) including a lip portion ( 442 ) adapted to slidably couple with one or more surfaces of the plate body ( 310 ), to allow for a longitudinal axis of the elongate coupler ( 420 ) to be nonparallel to a longitudinal axis of opening ( 340 ) of the plate ( 310 ).