Rod Locking Instrument

• US 20090228054A1
• Filed: 01/29/2009
• Published: 09/10/2009
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: Pioneer Surgical Technology Incorporated (Surgalign Holdings, Inc.)
• Original Assignee: Pioneer Surgical Technology Incorporated (Surgalign Holdings, Inc.)
• Inventors: Mohar, Joseph, Berrevoets, Gregory, Hoffman, Jeffrey, Norman, Maria M.
• Granted Patent: US 8,235,997 B2
• Time in Patent Office: Days
• US Class Current: 606/86.A
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• 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

Instruments and methods are provided for securing a spinal rod in one or more coupling devices secured to the spine by one or more anchor members. The instruments include members for grasping the coupling device and members for shifting one or more elements along a linear path to fix the position of an anchor member and/or fix the position of the rod with respect to the vertebra.

Claims

1. An instrument for locking a spinal rod to a rod coupling device, the instrument comprising:

an elongate instrument body having an axis;

at least one grasping member for securing the coupling device in a fixed position with respect to the instrument body;

a drive member for advancing a cap member in an axial direction toward the coupling device secured by the grasping member;

a shiftable reducing member for engaging the spinal rod and driving the spinal rod in the axial direction into engagement with the coupling device; and

a drive coupler for coupling the reducing member to the drive member so that the reducing member advances in the axial direction simultaneously with the drive member, the drive coupler having at least one portion that disengages from the reducing member with the reducing member advanced to a predetermined axial position with respect to the drive member so that the drive member is free to advance in the axial direction without further advancement of the reducing member in the axial direction.

2. The instrument of claim 1, wherein the coupling member comprises a pin member coupling a coupling sleeve member to the drive member and a shifting element configured to shift away from the coupling sleeve member to disengage the reducing member from the drive member.

3. The instrument of claim 1, further comprising an inhibitor switch that is shifted to a first position to limit axial advancement of the drive member by a first amount, and shifted to a second position to permit advancement by a second amount, the second amount being greater than the first amount.

4. The instrument of claim 1, further comprising a ratchet device for allowing sequential advancement of the drive member through a plurality of predetermined positions.

5. The instrument of claim 1, wherein the reducing member is an elongate hollow cylinder disposed about the drive member.

6. The instrument of claim 5, wherein the reducing member includes at least one slit to allow axial compression of the reducing member in an axial direction.

7. The instrument of claim 5, wherein the at least one slit is helical.

8. An instrument for locking an elongate member within a coupling assembly by axially shifting a cap member and insert member of the assembly relative to an outer member of the assembly, the instrument comprising:

a grasping device extending along an axis of the instrument and having an axial slit therein, the slit having a narrow portion and a wide portion;

opposed clamp portions disposed at one end of the grasping device and at opposite sides of the slit and configured to receive and grasp the coupling assembly outer member;

a drive member configured to receive the cap member;

a deflection member extending from the drive member and into the slit of the grasping device; and

an actuator operatively coupled to the drive member to shift the drive member parallel to the instrument axis;

wherein the clamp portions are deflected away from one another when the deflection member is located in the narrow portion of the slit, and the clamp portions shift toward one another when the deflection member of the drive member is shifted into the wide portion of the slit for clamping of the coupling assembly therebetween.

9. The instrument of claim 8 wherein the tulip grasping device comprises a sleeve and the drive member comprises an elongate member disposed axially within the sleeve.

10. The instrument of claim 8, the instrument further comprising a reducing member operatively coupled to the drive member and having an arcuate recess for engaging the elongate member as the drive member and reducing member are shifted toward the coupling assembly.

11. The instrument of claim 10, wherein the reducing member and drive member include a shiftable engagement member therebetween operable to couple the drive member and reducing member together in response to axial shifting of the reducing member until the reducing member is shifted to a predetermined position, and thereafter to decouple the drive member and reducing member after the reducing member is shifted to the predetermined position.

12. The instrument of claim 11, wherein the grasping device comprises a sleeve, the drive member comprises an elongate member sized to be disposed axially within the tulip grasping device sleeve, and the reducing member comprises a reducing sleeve sized to be disposed about the grasping member sleeve.