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 measurement from the displacement structure.

Abstract: A reamer may be designed to engage a guide member, such as a guide wire, implanted in bone at any of a plurality of relative orientations such that the resulting resection of the bone does not depend on the relative orientation. The reamer may have a shaft that receives torque and a reaming head with a cavity into which a protruding portion of the guide wire is insertable. The cavity may have a generally conical shape capable of receiving the guide wire at a variety of relative orientations. The orientation of the reaming head is determined not by that of the guide wire, but by a stationary frame to which the reamer is coupled. The reamer may optionally have an offset assembly that causes the reaming head to rotate about an axis displaced from that of the shaft to reduce the size of the incision required to reaming head.

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 facet joint replacement implant may have a posterior stabilization surface designed to restrict posterior motion of a vertebra with respect to an adjacent, inferior vertebra. The facet joint replacement implant replaces the natural articular surface of one of the vertebrae, and articulates with a natural articular surface or with an articular surface of a second implant on the other vertebra. The posterior stabilization surface may be on a posterior flange of a superior facet joint implant, which extends posteriorly of a corresponding inferior facet joint implant. The inferior facet joint implant has an abutment surface that abuts the posterior stabilization surface as the superior vertebra begins to move posteriorly with respect to the inferior vertebra, thereby limiting the posterior motion.

Abstract: Cephalad and caudal vertebral facet joint prostheses and methods of use are provided. A pair of fixation elements are adapted to be secured within a vertebra in an orientation that best assures a secure and durable attachment to cortical and/or cancellous bone. Artificial facet joint surfaces are mounted on the fixation elements, either directly or with the aid of a support. The artificial facet joint structure may be carried by an arm. The artificial facet joint structure is adapted for articulation with a complementary natural or artificial facet joint structure. Bilateral prostheses may by coupled by a brace to further secure and stabilize the prostheses.

Abstract: Modular spinal prosthesis having one of both of adaptable and configurable components is provided. The modular spinal prosthesis described herein provides an artificial articular configuration to replace damaged, worn or otherwise removed spinal facet elements.

Abstract: A prosthesis for the replacement of a diseased or traumatized facet of a mammalian vertebra includes a surface that articulates with another prosthetic facet or a natural facet, a portion that replaces at least a bony portion of the diseased or traumatized spine facet which is to be replaced, and an element to attach the prosthesis to the vertebra in a manner that does not require attachment to or abutment against the posterior arch. A method of installing the prosthesis includes the steps of resecting at least a portion of a facet and attaching the prosthesis in a manner that does not require attachment or abutment against the posterior arch.

Abstract: A prosthesis for the replacement of a diseased or traumatized facet of a mammalian vertebra includes a surface that articulates with another prosthetic facet or a natural facet, a portion that replaces at least a bony portion of the diseased or traumatized spine facet which is to be replaced, and an element to attach the prosthesis to the vertebra in a manner that does not require attachment to or abutment against the posterior arch. A method of installing the prosthesis includes the steps of resecting at least a portion of a facet and attaching the prosthesis in a manner that does not require attachment or abutment against the posterior arch.

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.

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 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 prosthetic replacement for a posterior element of a vertebra comprising portions that replace the natural lamina and the four natural facets. The prosthetic replacement may also include portions that replace one or more of the natural spinous process and the two natural transverse processes. If desired, the prosthesis replacement may also replace the natural pedicles. A method for replacing a posterior element of a vertebra is also provided.

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: 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 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.

Abstract: A prosthesis for the replacement of a diseased or traumatized facet of a mammalian vertebra includes a surface that articulates with another prosthetic facet or a natural facet, a portion that replaces at least a bony portion of the diseased or traumatized spine facet which is to be replaced, and an element to attach the prosthesis to the vertebra in a manner that does not require attachment to or abutment against the posterior arch. A method of installing the prosthesis includes the steps of resecting at least a portion of a facet and attaching the prosthesis in a manner that does not require attachment or abutment against the posterior arch.

Abstract: A prosthetic replacement for a posterior element of a vertebra comprising portions that replace the natural lamina and the four natural facets. The prosthetic replacement may also include portions that replace one or more of the natural spinous process and the two natural transverse processes. If desired, the prosthesis replacement may also replace the natural pedicles. A method for replacing a posterior element of a vertebra is also provided.