A minimally invasive intervertebral implant includes a circuitous body defining a luminal axis extending longitudinally therethrough. The circuitous body includes proximal and distal ends oppositely disposed along a lateral axis of the circuitous body. Each of the proximal and distal ends includes an aperture disposed therethrough such that the circuitous body includes a first configuration wherein the proximal and distal ends are at a maximum separation and a second configuration wherein the proximal and distal ends are closer together than in the first configuration.

A spacer for separating bones of a joint includes a frame and a carriage. The carriage has ramped surfaces, and is slideably moveable in relation to the frame. A screw support is moveably connected to the frame to form a changeable angular orientation with respect to the frame. An actuating screw is supported by the screw support, and is connected to the carriage to cause the carriage to slideably move in relation to the frame when the actuating screw is rotated. Opposing endplates are configured to engage opposing bone of the joint, and each has ramped surfaces mateable with the ramped surfaces of the carriage. When the carriage is moved by rotation of the actuating screw, the ramped surfaces of the carriage and the endplates slide against each other, causing the endplates to move relatively apart, to increase the height of the spacer.

An interbody fusion cage having upper and lower canals for receiving the heads of bone screws that have been pre-installed in opposing vertebral body endplates. The proximal wall of the cage preferably has a vertical slot that communicates with each canal and is adapted to allow access by a screwdriver and tightening of the screws.

A long-pitch, helical anchor includes splines radially extending and helically progressing circumferentially around and along the arcuate length of a curved center line (central curve). The center line may progress along the curved length of the anchor with all splines meeting near the center line. In other embodiments, the center line passes along the center of a lumen or channel from which the splines extend radially along the length. A solid point acts as a cutting edge on a distal end of the anchor. All the splines converge to the center line. Installation may be with or without a stabilizing frame, such as may be used to fill gaps and promote bone growth between joined members. The anchors may be used directly to connect and provide compression between two bones or bone structures.

An intervertebral cage structure that comprises a main body having a first surface and a second surface located opposite to the first surface, a first plate disposed on the first surface of the main body, a second plate disposed on the second surface of the main body, and an opening formed at a center portion of the intervertebral cage structure and extending from the first plate to the second plate via the main body, wherein at least one of the first and second plates comprise non-parallel undercut portions.

A stand-alone expandable interbody spinal fusion device, including a superior component, an inferior component, and an expansion mechanism operatively arranged to displace the superior component relative to the inferior component, the expansion mechanism including a threaded rod including a first end engaged with the superior component and a second end engaged with the inferior component, wherein when the threaded rod is rotated in a first circumferential direction, the superior component is displaced in a first direction relative to the inferior component.

An expandable intervertebral fusion implant, including an inferior component, including a first horizontal member, a first vertical member connected to the first horizontal member, and a first outward facing surface, a superior component hingedly connected to the inferior component, the superior component including a second horizontal member, a second vertical member connected to the second horizontal member, and a second outward facing surface directed away from the first outward facing surface, a first shell hingedly connected to the inferior component, and a first wedging component slidingly arranged between the first shell and the first outward facing surface.

A bellows shaped spinal implant, comprising an upper plate having an upper opening therethrough, a lower plate having a lower opening therethrough, and aa bellows shaped shell extending between and joining the upper plate and the lower plate. The bellows shaped shell is formed of titanium or an alloy comprising titanium and includes a wall extending continuously therearound that defines a hollow interior in communication with the upper opening and the lower opening. The wall has a thickness in the range of 0.5 mm to 1.0 mm to provide for radiographic imaging through the wall. The wall is angled or curved inwardly or outwardly between the upper plate and the lower plate to provide stiffness that mimics the stiffness properties of a similarly sized polyetheretherketone (PEEK) implant.

An expandable intervertebral implant is provided for insertion into an intervertebral space defined by adjacent vertebrae. The expandable intervertebral implant includes a pair of outer sleeve portions and an inner core disposed between the outer sleeve portions. Movement of the inner core relative to the outer sleeve portions causes the outers sleeve portions to deflect away from each other, thereby engaging the expandable intervertebral implant with the vertebrae and adjusting the height of the intervertebral space.

Interbody fusion devices, interbody fusion device systems, insertion tools, methods for assembling an interbody fusion device, and methods a method for inserting a medical device between two vertebral bodies are disclosed. The interbody fusion device includes a body member with a pivot cylinder, a superior member with a pivot channel that is configured to engage the pivot cylinder, and a movement mechanism for moving the superior member relative to the body member. The interbody fusion device systems may include an interbody fusion device and an insertion tool. Also disclosed is a method of assembling an interbody fusion device. In addition, a method for inserting a medical device between two vertebral bodies in a spine is disclosed.