Abstract: Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.

Abstract: Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.

Abstract: Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.

Abstract: Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.

Abstract: Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.

Abstract: A frame is attachable to first and second bone portions of a patient to facilitate measurement and resection of one or more bony landmarks. The frame has two anchoring features, each of which has a semispherical surface that permits rotational adjustment of the frame against the bone portions until the frame is secured. A bridging structure couples the anchoring features together such that the anchoring features are lockably movable with respect to each other. The bridging structure may have three linear sliders that provide the relative motion. A locking mechanism exerts pressure on all three sliders to lock them in place. An external anchoring feature enables attachment of the frame to a stationary reference to stabilize the frame. The frame also has registration features that permit attachment of measurement or resection tools to the frame. The frame is particularly useful for measuring and resecting spinal facets for facet replacement.

Abstract: Facet joint replacement implants may be designed for use on multiple adjacent vertebral levels. Each superior implant may have a substantially semispherical concave surface, and each inferior implant may have a cooperating semispherical convex surface that is deformable to enable it to be pressed into the superior implant concave surface to fix the relative orientations of the superior and inferior implants. Thus, the inferior implant may be attached to the same pedicle as the superior implant, but may also be oriented independently of the superior implant and then fixed in position. Similar mounting structures may be used to attach one or more fusion implants to a level adjacent to that of a facet joint replacement implant.

Abstract: A measurement tool is designed to measure the relative displacements between two bony landmarks of a spine, such as pedicles and facet surfaces. The measurement tool may have a registration interface designed to be registered to a first bony landmark, and a contact feature shaped to contact a second bony landmark. The registration interface may be registered to a frame rigidly coupled relative to the first bony landmark. The measurement tool also has a displacement structure that permits motion of the contact feature relative to the registration interface along multiple dimensions. The displacement structure may have two or three sliding joints that enable relative translation along orthogonal axes. Each sliding joint may have a rod with a plurality of markings that can easily be read to acquire measurements from the displacement structure.

Abstract: A system for replacing at least a portion of a natural facet joint includes a fixation member implantable in a vertebra, an inferior facet articular surface and an inferior strut which may be formed separately from the inferior articular surface. The inferior strut has a first end securable to the fixation member and a second end which may comprise a sphere with a hemispherical surface. An attachment mechanism may include a capture feature shaped to receive the second end of the inferior strut, and the mechanism may provide an adjustable configuration, allowing polyaxial adjustment between the inferior articular surface and the second end. A locking member may be actuated to exert force on the second end to provide a locked configuration. The system may further include a superior facet joint implant with a superior articular surface shaped to articulate with the inferior articular surface.

Abstract: A facet joint replacement system includes an inferior implant with an inferior articular surface, and a superior implant with a superior articular surface. The implants may be coupled together by a detachable coupler which can align and rigidly hold the inferior and superior articular surfaces in a preferred alignment relative to one another. A portion of the coupler may be deformable to allow detachment of the coupler from at least one of the implants. In one method of implantation, the superior and inferior implants may be aligned and coupled together with the coupler, and then secured to fixation members anchored in adjacent vertebrae. Alternatively, a first implant may be secured to a fixation member anchored in a first vertebra, and a second implant coupled to the coupler, aligned with the first implant and then secured to a fixation member anchored in a second vertebra. A tool may grip, position and/or deliver the coupler and the implants.

Abstract: A bone anchor assembly may include a fixation member securable to a bone, a coupling member, a compressible member and a locking member. The fixation member may be formed monolithically with the coupling member, and the coupling member may have a loop portion shaped to receive the compressible member. The compressible member may comprise a compressible sphere with a bore extending therethrough, the bore shaped to receive an elongated member. The locking member may be actuable through an aperture in the coupling member to urge compression of the compressible member to lock the elongated member in a fixed position. The compressible member may be polyaxially adjustable relative to the coupling member.

Abstract: A facet joint replacement system includes an inferior implant with an inferior articular surface, a superior implant with a superior articular surface and may include a crosslink extending across a vertebral sagittal plane. The inferior implant may comprise an inferior strut, and a polyaxially adjustable, lockable mechanism which may couple the inferior articular surface with a first end of the inferior strut, and couple the inferior articular surface with the crosslink. A second end of the inferior strut may be secured to a polyaxially adjustable, lockable fixation assembly securable in a vertebra. The superior implant may be secured to a polyaxially adjustable lockable fixation assembly securable in a vertebra. The positions of the inferior articular surface and the first end of the inferior strut are independently translatable along a medial-lateral axis of the vertebra prior to lockout by the lockable mechanism. The crosslink may be placed into the lockable mechanism from a posterior approach.

Abstract: A system for replacing at least a portion of a natural facet joint includes a fixation member implantable in a vertebra, an inferior facet articular surface and an inferior strut which may be formed separately from the inferior articular surface. The inferior strut has a first end securable to the fixation member and a second end which may comprise a sphere with a hemispherical surface. An attachment mechanism may include a capture feature shaped to receive the second end of the inferior strut, and the mechanism may provide an adjustable configuration, allowing polyaxial adjustment between the inferior articular surface and the second end. A locking member may be actuated to exert force on the second end to provide a locked configuration. The system may further include a superior facet joint implant with a superior articular surface shaped to articulate with the inferior articular surface.

Abstract: A system includes an implant with an articulation surface, a fixation member which may be anchored in a bone, and a base portion which may receive the fixation member. The base member may comprise a bone-engaging portion and an attachment portion. The base member may receive the fixation member such that a threaded portion of the fixation member and the bone-engaging portion of the base member may be seated in the bone. The implant may be attached to the attachment portion of the base member. The base member may be configured in a variety of shapes and may include fins, teeth, pegs or other anti-rotation features, and may include a bone ingrowth surface. The attachment portion may be tapered and attachable to the implant through a taper-lock.

Abstract: A prosthesis for the replacement of the cartilaginous structures of a spine motion segment is described. The prosthesis comprises an intervertebral disc prosthesis in combination with a facet joint prosthesis.

Abstract: A facet joint replacement system includes an inferior implant with an inferior articular surface, and a superior implant with a superior articular surface. The inferior implant may comprise an inferior strut, and a polyaxially adjustable, lockable mechanism which couples the inferior articular surface with a first end of the inferior strut. A second end of the inferior strut may be secured to a polyaxially adjustable, lockable fixation assembly securable in a vertebra. The first end of the inferior strut may be post-shaped, and the second end ring-shaped, and vice versa. The superior implant may be secured to a polyaxially adjustable lockable fixation assembly securable in a vertebra. Inferior and superior implants may be implanted individually, paired on one lateral vertebral side, bi-laterally, and/or in multiple vertebral levels. A crosslink may be secured to one implant and extend across a vertebral sagittal plane to a second implant. A clip may align the articular surfaces during implantation.

Abstract: A fixation system is designed to lock an elongated member within a housing member, permitting positional and/or orientational adjustment of the elongated member prior to locking. The system includes a housing member, a slotted spherical collet, an elongated member, and may include a tapered wedge, which may be a discrete component or formed as part of the elongated member. The housing member and/or elongated member may be implantable. The elongated member may be positioned in the wedge, the wedge in the collet, and the collet in the housing such that when compression force is applied to the wedge and the collet, the wedge contracts about the elongated member and the collet expands to engage the housing, thus locking the elongated member relative to the housing. The collet may have a tapered channel with a degree of taper equal to the tapered wedge. The collet may have multiple slots to allow uniform radial expansion and compression.

Abstract: A prosthesis for the replacement of at least a portion of the bone of a facet located on a mammalian vertebra, comprising: an articulating surface that articulates with another facet; a bone contacting surface that contacts a surface of the vertebra, the articulating surface being connected to the bone contacting surface; and a fixation element that attaches the bone contacting surface to the vertebra, the fixation element being adapted for implantation into an interior bone space of a pedicle of the vertebra; wherein the prosthesis is configured so that no portion of the prosthesis contacts the posterior arch of the vertebra.

Abstract: A prosthesis for the replacement of the cartilaginous structures of a spine motion segment is described. The prosthesis comprises an intervertebral disc prosthesis in combination with a facet joint prosthesis.

Abstract: A prosthesis for the replacement of multiple diseased or traumatized spinal facets comprises a portion that replaces at least a bony portion of the facets to be replaced and where the prosthesis attaches to the vertebra in a manner that does not require attachment to, or abutment against, the lamina. Multiple configurations of the prosthesis provide for replacement of the two inferior facets, the two superior facets, a superior and inferior facet, or all four facets. A method of installing the prosthesis is provided that is comprised of the steps of resecting at least a portion of the facets that carry the diseased or traumatized spinal facets and attaching the prosthesis in a manner that does not require attachment or abutment against the lamina.