Abstract: An improved mechanism for expanding or lifting a device in accordance with various embodiments of the present invention is a coaxial screw gear sleeve mechanism. In various embodiments, coaxial screw gear sleeve mechanisms includes 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 a device utilizing such a mechanism to expand or lift between a collapsed configuration and an expanded configuration.

Abstract: Improved flexible joint arrangements employ at least one flexure member that interfaces with wrapping surfaces defined on the bases to which the ends of the flexure member are connected. The flexure members are configured to define a traveling instantaneous axis of rotation that moves along a path defined by the interface of the flexure and the wrapping surfaces as the bases move relative to each other. The flexure members and the bases can be constructed of a monolithic material. The wrapping surfaces of the bases can be asymmetric in cross-sectional shape. The radius of curvature of the traveling instantaneous axis of rotation can be configured to change only in discrete quantum steps without reversals. In other embodiments, the flexible joint arrangement can be configured as one or more three bar linkages in which the middle bar is rigid and the outer bars are flexure members in accordance with the various embodiments.

Abstract: Improved methods and apparatuses for vertebral body distraction and fusion in accordance with various embodiments of the present invention employ flexure members. Flexure members connect a plurality of structural members to end plates on one end and blocks on another end. Upon insertion into the disc space, a drive screw or similar mechanism can be actuated to drive expansion blocks closer together, which causes flexure members to deflect, resulting in expansion of the structural members and distraction of the end plates. The distracted device can then remain in the body and be used for vertebral body fusion.