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.

Robotic system and methods for preparing a bone of a joint to receive an implant. Virtual object(s) are used to define a volume of material to be removed from the bone for receipt of the implant. A robotic manipulator controls a cutting tool based on the virtual object(s) to form a first cavity and a second cavity in the bone. The second cavity is formed beneath the first cavity and is rotated relative to the first cavity to define an undercut in the bone. The first and second cavities receive a body and a locking member of the implant in an unlocked position. The locking member is rotated within the second cavity to a locked position whereby the undercut engages the locking member to limit withdrawal of the implant from the bone.

An intervertebral implant includes a body with a first face, a second face connected to the first face, and an axis of rotation. The body defines a hollow space for connecting to an insertion device, the hollow space being accessible through an opening formed between the first and second faces. The opening is elongate and extends around the axis of rotation to facilitate pivoting of the implant relative to the insertion device about the axis of rotation to a first angular position and a second angular position. The implant further includes a first abutment surface that engages the insertion device in a form-fit manner at the first angular position, and a second abutment surface that engages the insertion device in a form-fit manner at the second angular position. The opening can also engage the insertion device to hold the implant at least one additional angular position.

Disclosed is a system to assist in a procedure. During the procedure an object may be moved relative to a subject, such as being positioned and/or placed within a subject. The system and related method may be used to assist in displaying and/or determining a pose of the object relative to a subject, such as rigid portions of a subject.

Medical devices in accordance with various embodiments of the present invention employ one or more coaxial screw gear sleeve mechanisms. In various embodiments, coaxial screw gear sleeve mechanisms include a post with a threaded exterior surface and a corresponding sleeve configured to surround the post, the corresponding sleeve having a threaded interior surface configured to interface with the threaded exterior surface of the post and a geared exterior surface. A drive mechanism can be configured to interface with the geared exterior surface of the sleeve, causing the device to expand.

Robotic surgical systems and methods for preparing a glenoid for a receiving an implant in a shoulder joint replacement surgery. A control system associates, with the glenoid, a virtual boundary that defines a volume of material that should be removed from the glenoid and a virtual line haptic being defined based on a planned trajectory of a screw to be implanted into the glenoid to facilitate installation of the implant. The control system controls a robotic manipulator to operate and constrain a first cutting tool relative to the virtual boundary to remove the volume of material from the glenoid to prepare a surface of the glenoid to receive a base of the implant. The control system controls the robotic manipulator to operate and constrain a second cutting tool relative to the virtual line haptic to form a center hole within the glenoid to receive the screw.

An intervertebral implant has a hollow space formed within the implant and accessible through an elongate opening extending through a recessed portion of the side wall, and the hollow space is shaped to receive an engagement portion of a drive shaft of an insertion tool; and the intervertebral implant includes at least two guiding surfaces facing each other and being configured for sliding engagement by a portion of a sleeve of the insertion tool movably holding the drive shaft.

Medical devices in accordance with various embodiments of the present invention employ one or more coaxial screw gear sleeve mechanisms. In various embodiments, coaxial screw gear sleeve mechanisms include a post with a threaded exterior surface and a corresponding sleeve configured to surround the post, the corresponding sleeve having a threaded interior surface configured to interface with the threaded exterior surface of the post and a geared exterior surface. A drive mechanism can be configured to interface with the geared exterior surface of the sleeve, causing the device to expand.