Expandable interfusion cage

• US 20050113917A1
• Filed: 11/21/2003
• Published: 05/26/2005
• Est. Priority Date: 11/21/2003
• Status: Active Grant

• Current Assignee: Kyungwon Medical Co., Ltd.
• Original Assignee: Kyungwon Medical Co., Ltd.
• Inventors: Youn, Jae-Ryoun, Cho, Yong-Eun, Chae, Soo-Kyung, Kim, Sang-Taek, Yoon, Do-Heum, Park, Hyung-Sang
• Granted Patent: US 6,955,691 B2
• Time in Patent Office: Days
• US Class Current: 623/17.110
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30892 parallel

Abstract

An expandable interfusion cage comprising a cage body and a spacer. The cage body includes a seat part which is pierced by an orifice and a branch part which defines therein an inside space and has a plurality of elongate branches integrally formed at their proximal ends with the seat part. An opening is defined between two adjoining branches to communicate with the inside space. The spacer is movably assembled in the inside space of the cage body to expand the cage body radially outward. Inward projections are formed at distal ends, respectively, of the branches to project radially inward toward an axis of the cage body. The inside space of the cage body has substantially a circular or polygonal sectional shape. The spacer is engaged with the inward projections of the branches while expanding the cage body.

Claims

1. An expandable interfusion cage comprising a cage body of a quadrangular or cylindrical shape and a spacer, the cage body including a seat part which is pierced by an orifice and a branch part which defines therein an inside space and has a plurality of elongate branches integrally formed at their proximal ends with the seat part, with an opening defined between two adjoining branches to communicate with the inside space, the spacer being movably assembled in the inside space of the cage body to expand the cage body radially outward, wherein inward projections are formed at distal ends, respectively, of the branches constituting the branch part to project radially inward toward an axis of the cage body, the inside space of the cage body has substantially a circular or polygonal sectional shape, and the spacer is engaged with the inward projections of the branches while expanding the cage body.

2. The expandable interfusion cage as set forth in claim 1, wherein the spacer has a head portion which possesses a bullet-shaped configuration and a base portion which possesses a disk-shaped configuration, and is defined with an annular groove between the head portion and the base portion.

3. The expandable interfusion cage as set forth in claim 1, wherein the base portion of the spacer is formed to serve as an engaging plate which has a diameter larger than that of the head portion, and a plurality of engaging protuberances each having a downwardly inclined face are formed on an outer surface of the spacer below the head portion to be spaced apart one from another in a circumferential direction, in a manner such that the inward projections formed at the distal ends of the respective branches are engaged between the engaging plate and the engaging protuberances.

4. (canceled).

5. An expandable interfusion cage, comprising a cage body including a seat part provided with an orifice and a branch part defining an inside space and having a plurality of elongate branches formed at their proximal ends integrally with said seat part, said branches including two adjoining branches defining an opening which communicates with said inside space, said branch part having a guiding slit communicating with said opening and defined between said two adjoining branches when viewed on distal end surfaces of said branches, so that four said guiding slits are formed and cooperate to create a cross-shaped space;

and a spacer movably arranged in said inside space of said cage body and having a substantially cylindrical spacer body with a head portion which is formed as a cross-shaped protrusion biasing said branches radially outwardly, and a base portion formed as a disc with a diameter larger than a diameter of said head portion and having a pair of guide pieces oppositely formed at both sides of said disc and engaging in said guiding slits.

6. An expandable interfusion cage as defined in claim 5, wherein said cage body has a shape selected from the group consisting of a quadrangular shape and a cylindrical shape.