HEIGHT ADJUSTABLE SPINAL PROSTHESES

摘要

Dimensionally adjustable spinal prostheses are adjustable in an axial or superior to inferior dimension such that spinal prostheses may assume variations in height. The height adjustable spinal prostheses are characterized by first and second portions that are configured for adjustable coupling with one another. Spatial adjustment between the first and second portions is provided by an adjustment assembly. The adjustment mechanism preferably, but not necessarily, provides infinite adjustment over a minimum prosthesis height to a maximum prosthesis height. In one form, first and second ends of the height adjustable spinal prostheses are configured to receive an endplate. The endplates aid in attachment and/or anchoring of the spinal prosthesis within the spine. The endplates may be fashioned in various configurations such as circular or anatomical. In one form, the adjustment assembly utilizes rotational motion for varying the axial position of one prosthetic portion relative to the other prosthetic portion. Rotational movement of an adjustment mechanism of the adjustment assembly is translated into axial movement of one prosthetic portion relative to the other prosthetic portion. In another form, the adjustment mechanism is a screw and gearing assembly. In yet another form, the adjustment mechanism is a rack and pinion assembly.

主权项

1. A spinal prosthesis comprising:
a first prosthetic portion having a body defining an interior chamber, a first hub extending from the body, and a first collar extending axially between the body and the first hub, the first collar only partially surrounding the first hub; a second prosthetic portion at least partially received in the interior chamber of the first prosthetic portion, the second prosthetic portion axially displaceable relative to the first prosthetic portion, the second prosthetic portion having a body, a second hub extending from the body, and a second collar extending axially between the body and the second hub, the second collar only partially surroundings the second hub; an adjustment mechanism coupled to the first and second prosthetic portions within the bodies of the first and second prosthetic portions and operable to effect axial displacement of the second prosthetic portion relative to the first prosthetic portion; a first end plate received on the first hub and situated on the first collar of the first prosthetic portion; and a second end plate received on the second hub and situated on the second collar of the second prosthetic portion; wherein the first collar is structured to control an angular freedom of the first end plate; and wherein the second collar is structured to control an angular freedom of the second end plate.