Stabilizing vertebrae with articulating implants

Inventors

Weiman, Mark • Glerum, Chad • Hessler, Ty • Hill, Albert

Assignees

Globus Medical Inc

Abstract

A bone joint spacer has two endplates which have a bone engaging surface on one side, and ramps extending from an opposite side. A shaft has a threaded end, and another end which has ramp followers which mate with the endplate ramps of both endplates. A collar slides over the threaded end of the shaft, and also has ramp followers which mate with the endplate ramps of both endplates. A nut threads onto the end of the shaft and pushes the collar towards the ramp followers of the shaft. This movement causes the ramp followers to slide the ramp followers of the collar and the shaft against the endplate ramps, pushing the endplates apart. Two of these spacers can be combined by a link plate so that the spacers can be aligned or curved into a U-shape to be inserted into the body and positioned between bony surfaces, respectively.

Core Innovation

The described invention provides an articulating interbody spacer/implant for separating bones of a joint, specifically including first and second driven modules with first and second endplates. Each endplate has a first side forming a bone engaging surface, a second side opposite the first side, and first and second angled sides extending from the first side in the direction of the second side.

The spacer includes a single-piece shaft with a first end and a second end mateable with the second side of one of the endplates, and a collar slidably disposed upon the shaft proximate the shaft first end. A nut threadably engaged with the shaft first end pushes the collar toward the shaft second end to move the first and second endplates from a collapsed position to an expanded position, while a pair of link plates pivotally joined to one of the endplates by a hinge connection expand vertically in the same direction and push against the bones to separate the bones of the joint.

In the collapsed position, the first angled side of the first endplate engages the first angled side of the second endplate, and the first angled side of the first endplate extends to the first side of the second endplate while the first angled side of the second endplate extends to the first side of the first endplate. In the expanded position, the angled sides separate and the endplates are spaced apart relative to each other, and the disclosed variations further specify ramp-based mating with ramp followers, endplate openings for reduced height, and connection features for forming straight or U-shaped profiles.

The background problem being solved is vertebral stabilization and fusion by separating vertebral bones with an interbody implant that supports endplate spacing while enabling controlled positioning and correction, including restoration of lordosis and posterior height and coronal correction. The described solution addresses a need for a spacer that can be driven from a collapsed to an expanded position using a nut, while maintaining bone engaging action through endplates and link plates.

Claims Coverage

The provided independent claims include three inventive claim sets. Across the independent claims, the coverage centers on nut-driven translation of a collar on a shaft to move angled endplates from a collapsed to an expanded position, and hinge-connected link plates that expand vertically to push bone engaging surfaces against bones to separate the bones of the joint.

The independent claims collectively define a spacer that separates bones by nut-driven expansion: a collar translated on a shaft pushes endplates from a collapsed to an expanded state, and hinge-connected link plates expand vertically with the driven modules to push bone engaging surfaces against the bones. The claimed endplates exhibit specific angled-side engagement in the collapsed position and separation in the expanded position.

Stated Advantages

Documented Applications