Spacer with adjustable axial length

• US 6,200,348 B1
• Filed: 10/04/1999
• Issued: 03/13/2001
• Est. Priority Date: 02/06/1998
• Status: Expired due to Term

• Current Assignee: Biedermann Technologies GmbH & Co. KG
• Original Assignee: Biedermann Motech GmbH
• Inventors: Biedermann, Lutz, Harms, Jürgen
• Primary Examiner(s): Hirsch, Paul J.
• Assistant Examiner(s): Priddy, Michael B.
• Application Number:
  US09/402,425
• Time in Patent Office: 526 Days
• Field of Search: 606/60, 606/61, 606/69, 606/72, 606/73, 606/90, 623/17.11, 623/17.16
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30148 lozenge- or diamond-shaped
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30372 with additional means for limiting said translation
• CPC Class Codes: A61F 2002/30378 Spherically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30479 using a locking ball
• CPC Class Codes: A61F 2002/30505 spring biased
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30574 with an integral complete or partial collar or flange
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30808 parallel
• CPC Class Codes: A61F 2002/30845 : with cutting edges
• CPC Class Codes: A61F 2002/30912 : made of expanded metal, e.g. diamond mesh or metal nets having lozenge-shaped apertures
• CPC Class Codes: A61F 2002/4638 : Tools for performing screwing, e.g. nut or screwdrivers, or particular adaptations therefor
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical

Abstract

A spacer for insertion between two vertebrae has a variable axial length. The spacer comprises a first sleeve-shaped shape member 1 and a second member 2 which is slidably guided within the first member in axial direction relative thereto for adjusting the overall length. The second member 2 comprises, on its outer portion facing the first member 1, an axially extending portion having ratchet notch means 18, and the first member 1 has an engagement member 23 cooperating with the ratchet notch means 18 for displacement to a desired overall length.

Claims

1. A spacer for insertion between two vertebrae, said spacer having a variable axial length and comprising a sleeve-shaped first member and a second member guided within the first member to be slidable relative thereto in an axial direction thereof for adjusting an overall length,

wherein the second member comprises an outer wall and ratchet notches provided at its outer wall facing the first member and extending in the axial direction, and

wherein the first member comprises a wall having an engagement member, which cooperates with the ratchet notches for adjusting a desired overall length of the spacer.

2. A spacer according to claim 1, wherein the engagement member is inserted into the wall of the first member and has a spring-biased ratchet member, and

the spacer member further comprises a locking member that cooperates with the ratchet notches for locking both the first and second members at the desired overall length.

3. A spacer according to claim 2, wherein the ratchet notches comprise a plurality of axially spaced recesses, and wherein the ratchet member comprises a spring-biased ball.

4. A spacer according to claim 3, wherein the recesses comprise hollow, spherical segments.

5. A spacer according to claim 4, wherein a pitch of the centers of two adjacent recesses is less than the ball diameter.

6. A spacer according to claim 4, wherein a pitch of the centers of two adjacent recesses is less than the diameter of the peripheral edge of the recess.

7. A spacer according to any one of the claims 2 to 6, wherein the locking member comprises a screw having an end face facing the ratchet notches and a spherical segment, which is provided on the end face of the screw and is dimensioned to exactly fit a recess.

8. A spacer according to any one of the claims 2 to 6, wherein the first member comprises a first threaded bore for receiving the engagement member and a second threaded bore disposed above or below the first threaded bore and in a direction of a center axis for receiving the locking member.

9. A spacer according to any of the claim 7, wherein the first member comprises a first threaded bore for receiving the engagement member and a second threaded bore disposed above or below the first threaded bore and in a direction of a center axis for receiving the locking member.

10. A spacer according to any one of the claims 2 to 6, wherein the first and second members have free ends that are serrated.

11. A spacer according to any one of the claim 2 to 6, wherein the walls of both first and second members comprise a plurality of apertures formed such that a plurality of said apertures around a circumferential direction at least partially coincide in each ratchet position.

12. A spacer according to claim 10, wherein the walls of both first and second members comprise a plurality of apertures formed such that a plurality of said apertures around a circumferential direction at least partially coincide in each ratchet position.

13. A spacer according to any one of the claims 2 to 6, wherein a stop is provided for limiting a relative displacement to provide a maximum overall length of the spacer.