Articulated vertebral body spacer

• US 5,534,029 A
• Filed: 12/01/1993
• Issued: 07/09/1996
• Est. Priority Date: 12/14/1992
• Status: Expired due to Fees

• Current Assignee: Yumiko Shima
• Original Assignee: Yumiko Shima
• Inventors: Shima, Toshio
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/160,487
• Time in Patent Office: 951 Days
• Field of Search: 623/17-18, 623/2030, 606/60, 606/61, 606/62, 606/63, 606/64
• US Class Current: 623/17.15
• CPC Class Codes: A61B 2090/061 for measuring dimensions, e.g. length
• CPC Class Codes: A61B 2090/062 penetration depth
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30599 stackable
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30662 with rotation-limiting means
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/443 having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/4661 for measuring thickness
• CPC Class Codes: A61F 2002/4662 for measuring penetration depth
• CPC Class Codes: A61F 2230/0019 rectangular
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: Y10S 606/907 : Composed of particular material or coated

Abstract

An articulated vertebral body spacer is constituted by a pair of upper and lower joint pieces to be inserted between vertebras. The lower joint piece includes a convex portion formed on a central portion of its upper surface and having a convex sliding contact surface, and a stopper surface surrounding the convex portion. The upper joint piece includes a concave portion formed on a central portion of its lower surface and having a concave sliding contact surface which is sliding contact with the convex sliding contact surface, and an abutment surface which surrounds the concave portion and abuts against the stopper surface. A cavity for allowing the upper joint piece to pivot in accordance with forward/backward and bending motions of vertebral bodies to respective levels is formed between the abutment surface and the stopper surface.

Claims

1. An articulated vertebral body spacer comprising:

upper and lower joint pieces to be inserted between vertebras, and at least one intermediate vertebral body interposed between said upper and lower joint pieces, said spacer defining first and rear sides,

said lower joint piece including a convex portion formed on a central portion of an upper surface thereof and having a convex sliding contact surface, a stopper surface surrounding the convex portion, and a plurality of projections provided on a lower surface of the lower joint piece,

said upper joint piece including a concave portion formed on a central portion of a lower surface thereof and having a concave sliding contact surface, an abutment surface which surrounds the concave portion, and a plurality of projections provided on an upper surface of the upper joint piece, and

said intermediate vertebral body including a concave portion formed on a central portion of a lower surface thereof and having a concave sliding contact surface which is in sliding contact with the convex sliding contact surface of said lower joint piece, an abutment surface surrounding the concave portion and abutting against the stopper surface of said lower joint piece, a convex portion formed on a central portion of an upper surface of said intermediate vertebral body and having a convex surface which is in sliding contact with the concave sliding contact surface of said upper joint piece, and a stopper surface surrounding the convex portion and abutting against the abutment surface of said upper joint piece,

wherein the stopper surface of said lower joint piece and the abutment surface of said intermediate vertebral body and between the abutment surface of said upper joint piece and the stopper surface of said intermediate vertebral body define gaps such that said gaps formed in said front side are larger than said gaps formed in said rear side.

2. A spacer according to claim 1, wherein movement preventing structures are formed on the lower surface of said lower joint piece and the upper surface of said upper joint piece.

3. A spacer according to claim 1, wherein the stopper surface is formed such that a front surface side portion is lower than a central side portion.

4. A spacer according to claim 1, wherein each of the gaps is determined such that a front side gap is larger than a rear side gap in an upright posture.