Auxiliary instrument for fixing rod

• US 7,909,835 B2
• Filed: 03/08/2005
• Issued: 03/22/2011
• Est. Priority Date: 03/09/2004
• Status: Active Grant

• Current Assignee: Showa Ika Kohgyo Co., Ltd.
• Original Assignee: Showa Ika Kohgyo Co., Ltd.
• Inventors: Takamido, Hiroshi, Oribe, Kazuya
• Primary Examiner(s): Robert; Eduardo C
• Assistant Examiner(s): Carter; Tara R
• Application Number:
  US11/073,590
• Publication Number:
  US 20050261702A1
• Time in Patent Office: 2,205 Days
• Field of Search: 606/246, 606/264, 606/279, 606/86.A, 606/86.R, 606/99, 606/104, 606/207, 606/72, 606/53, 606/54, 606/100, 606205-208, 606/210, 606/211, 81/36, 81/37, 813/00, 813/04, 813/21, 813/42, 813/45, 813/50, 813/78, 814/20, 814/85, 712/5, 712/6
• US Class Current: 606/104
• CPC Class Codes: A61B 17/7086 Rod reducers, i.e. devices providing a mechanical advantage to allow a user to force a rod into or onto an anchor head other than by means of a rod-to-bone anchor locking element; rod removers

Abstract

An auxiliary instrument for fixing a rod places a detent pin on a head portion of the screw. The auxiliary instrument comprises an inner cylinder, an outer cylinder, a first lever and a second lever. The inner cylinder has a plurality of claw portions and an opening employed to introduce the detent pin into an interior thereof. The outer cylinder is arranged to surround the inner cylinder and has a claw pressing portion. The first lever is rotatably connected to the inner cylinder and arranged in substantially perpendicular to an axial direction of the inner cylinder. The second lever is rotatably connected to the fist lever and the outer cylinder and arranged in substantially perpendicular to an axial direction of the outer cylinder. When the first and second levers are operated, the claw portions are pressed inward by the claw pressing portion to hold the head portion of the screw.

Claims

1. An auxiliary instrument for fixing a rod, the auxiliary instrument placing a detent pin employed to fix the rod to a screw on a head portion of the screw, the auxiliary instrument comprising:

an inner cylinder member having a plurality of claw portions at a first end portion thereof and an opening employed to introduce the detent pin into an interior thereof at a second end portion thereof, the inner cylinder member further having a first bracket disposed at the second end portion thereof such that the first bracket projects from the inner cylinder member in a direction generally perpendicular to a longitudinal axial direction of the inner cylinder member;

an outer cylinder member arranged to surround the inner cylinder member and having a claw pressing portion at a first end portion thereof, the outer cylinder member further having a second bracket at a second end portion thereof such that the second bracket projects from the outer cylinder member in generally a same direction as the first bracket;

a first lever rotatably connected to the first bracket of the inner cylinder member such that the first lever is extended from the first bracket; and

a second lever rotatably connected to the first lever and the second bracket of the outer cylinder member such that the second lever is extended from the second bracket,

wherein the claw portions are pressed inward by the claw pressing portion to hold the head portion of the screw when the first lever and the second lever are operated.

2. The auxiliary instrument for fixing a rod according to claim 1, wherein the claw portions approach one another as being guided by the claw pressing portion formed on an inner circumference surface of the outer cylinder member when the outer cylinder member moves downward relative to the inner cylinder member.

3. The auxiliary instrument for fixing a rod according to claim 2, wherein the inner cylinder member branches in two directions tapering outwardly from the vicinity of a center portion to the first end portion thereof.

4. The auxiliary instrument for fixing a rod according to claim 3, wherein each of the claw portions has a groove configured to restrain the head portion of the screw in three directions.

5. The auxiliary instrument for fixing a rod according to claim 3, wherein the outer cylinder member has a rod holding portion configured to press the rod toward the head portion of the screw at the first end thereof.

6. The auxiliary instrument for fixing a rod according to claim 4, wherein each groove has an engaging pin to be engaged into an engaging hole formed on the head portion of the screw.

7. The auxiliary instrument for fixing a rod according to claim 1, further comprising:

a biasing member mounted between the first lever and the second lever and configured to bring a base end portion of the first lever close to a base end portion of the second lever.

8. The auxiliary instrument for fixing a rod according to claim 7, further comprising:

a locking member mounted to a free end portion of the first lever and configured to engage a free end portion of the second lever and configured to hold the base end portions in a manner separated from each other against a biasing force of the biasing member.

9. The auxiliary instrument for fixing a rod according to claim 1, wherein the inner cylinder member is configured to receive a rotating tool.

10. The auxiliary instrument for fixing a rod according to claim 9, wherein when the rotating tool is inserted in the inner cylinder member, the rotating tool is disposed perpendicular to the first lever and the second lever.

11. The auxiliary instrument for fixing a rod according to claim 1, wherein the first lever is connected to the first bracket through a hinge pin.

12. The auxiliary instrument for fixing a rod according to claim 1, wherein the second lever is connected to the second bracket through a hinge pin.

13. The auxiliary instrument for fixing a rod according to claim 1, wherein the claw portions are configured to grasp the head portion of the screw on sides thereof.

14. An auxiliary instrument for fixing a rod, the auxiliary instrument placing a detent pin employed to fix the rod to a screw on a head portion of the screw, the auxiliary instrument comprising:

an inner cylinder member having a plurality of claw portions at a first end portion thereof and an opening employed to introduce the detent pin into an interior thereof at a second end portion thereof, the inner cylinder member further having a first bracket disposed at the second end portion thereof;

an outer cylinder member arranged to surround the inner cylinder member and having a claw pressing portion at a first end portion thereof, the outer cylinder member further having a second bracket disposed at a second end portion thereof;

a first lever pivotally connected to the first bracket of the inner cylinder member through a hinge pin; and

a second lever pivotally connected to the second bracket of the outer cylinder member through a hinge pin and pivotally connected to the first lever through a pivot,

wherein the claw portions are pressed inward by the claw pressing portion to hold the head portion of the screw when the first lever and the second lever are operated.

15. The An auxiliary instrument for fixing a rod according to claim 14, wherein the inner cylinder member is configured to receive a rotating tool.

16. The An auxiliary instrument for fixing a rod according to claim 15, wherein when the rotating tool is inserted in the inner cylinder member, the rotating tool is disposed perpendicular to the first lever and the second lever.

17. An auxiliary instrument for fixing a rod, the auxiliary instrument placing a detent pin employed to fix the rod to a screw on a head portion of the screw, the auxiliary instrument comprising:

an inner cylinder member having a plurality of claw portions at a first end portion thereof and an opening employed to introduce the detent pin into an interior thereof at a second end portion thereof, the inner cylinder member further having a first bracket disposed at the second end portion thereof;

an outer cylinder member arranged to surround the inner cylinder member and having a claw pressing portion at a first end portion thereof, the outer cylinder member further having a second bracket disposed at a second end portion thereof;

a first lever rotatably connected to the first bracket of the inner cylinder member through a hinge pin and crossing a longitudinal direction of the inner cylinder member, the first lever configured to pivot in a plane including the longitudinal direction of the inner cylinder member; and

a second lever rotatably connected to the first lever and the second bracket of the outer cylinder member through a hinge pin and crossing a longitudinal direction of the outer cylinder member, the second lever configured to pivot in a plane including the longitudinal direction of the outer cylinder member,

wherein the claw portions are pressed inward by the claw pressing portion to hold the head portion of the screw when the first lever and the second lever are operated.

18. The An auxiliary instrument for fixing a rod according to claim 17, wherein the inner cylinder member is configured to receive a rotating tool.

19. The An auxiliary instrument for fixing a rod according to claim 18, wherein when the rotating tool is inserted in the inner cylinder member, the rotating tool is disposed perpendicular to the first lever and the second lever.

20. An auxiliary instrument for fixing a rod, the auxiliary instrument placing a detent pin employed to fix the rod to a screw on a head portion of the screw, the auxiliary instrument comprising:

an inner cylinder member having a plurality of claw portions at a first end portion and an opening employed to introduce the detent pin into an interior thereof at a second end portion thereof, the inner cylinder member further having a first bracket disposed at the second end portion thereof such that the first bracket projects in a direction generally perpendicular to a longitudinal axis of the inner cylinder member;

an outer cylinder member arranged to surround the inner cylinder member and having a claw pressing portion at a first end portion thereof, the outer cylinder member further having a second bracket disposed at a second end portion thereof such that the second bracket projects in generally a same direction as the first bracket;

a first lever rotatably connected to the first bracket of the inner cylinder member and arranged generally perpendicular to a longitudinal direction of the inner cylinder member and movable along a longitudinal axial direction of the inner cylinder member; and

a second lever rotatably connected to the first lever and the second bracket of the outer cylinder member and arranged such that the second lever is pivotally moved on a same plane as the movement of the first lever along a longitudinal axial direction of the outer cylinder member,

wherein the claw portions are pressed inward by the claw pressing portion to hold the head portion of the screw when the first lever and the second lever are operated.