Spinal Rod Reducer and Cap Insertion Apparatus

• US 20090157125A1
• Filed: 02/14/2008
• Published: 06/18/2009
• Est. Priority Date: 02/14/2007
• Status: Active Grant

• Current Assignee: Pioneer Surgical Technology Incorporated (Surgalign Holdings, Inc.)
• Original Assignee: Pioneer Surgical Technology Incorporated (Surgalign Holdings, Inc.)
• Inventors: Norman, Maria M., Ensign, Michael D., Hoffman, Jeffrey, Perrow, Scott J.
• Granted Patent: US 8,308,774 B2
• Time in Patent Office: Days
• US Class Current: 606/86.A
• 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
• CPC Class Codes: A61B 17/7091 for applying, tightening or removing longitudinal element-to-bone anchor locking elements, e.g. caps, set screws, nuts or wedges

Abstract

A medical instrument apparatus and method is provided for positioning and securing a spinal rod to a coupling device anchored to a vertebra. A reducer assembly shifts the spinal rod into place within the coupling device and a cap inserter assembly shifts a cap member into locking engagement with the coupling device to secure the spinal rod therein.

Claims

1. An apparatus for shifting a spinal rod into a coupling assembly and securing the rod to the coupling assembly with a cap member, comprising:

a) a reducer assembly having a central axis, the reducer assembly having;

a clamp portion for clamping the coupling assembly to the reducer assembly; and

a reducing member for shifting the spinal rod into the coupling assembly;

b) a cap inserter having a shiftable drive member to drive the cap member into the coupling assembly to lock the rod with respect to the coupling assembly;

c) a throughbore of the reducer assembly into which the cap inserter drive member extends; and

d) a releasable coupling between the reducer assembly and the cap inserter to allow the reducer assembly to first reduce the spinal rod prior to coupling of the cap inserter to the reducer assembly, and thereafter allowing the position of a portion of the cap inserter to be fixed into position with respect to the throughbore of the reducer assembly via the releasable coupling to drive the cap member into the coupling assembly for locking of the rod therein.

2. The apparatus of claim 1, wherein reducing member is a sleeve configured to cause radial clamping of the clamp portion as the reducing member sleeve shifts along the central axis of the reducer assembly.

3. The apparatus of claim 1, further comprising a rotatable drive mechanism configured to advance the reducing member toward the spinal rod when rotated.

4. The apparatus of claim 3, further comprising a drive release mechanism for disengaging the drive mechanism to allow manual advancement of the reducing member without use of the drive mechanism.

5. The apparatus of claim 1, wherein the cap inserter further comprises a selector switch to allow shifting of the drive member to a first position when the switch is in a first orientation and to allow shifting of the drive member to a second position when the switch is in a second orientation.

6. The apparatus of claim 1, wherein the cap inserter comprises a locking mechanism for securing the cap inserter to the reducer assembly so that force applied to the shiftable drive member is directed toward the clamp portion of the reducer assembly clamped to the coupling assembly.

7. The apparatus of claim 1, wherein the locking mechanism comprises a radially shifting portion that shifts radially with respect to the central axis of the reducer assembly in response to axial shifting of the drive member.

8. A method for securing a spinal rod to a vertebra, the method comprising:

securing a fixation device to the vertebra;

securing a coupling device to the fixation device;

disposing the spinal rod within a rod reducing assembly and clamping the rod reducing assembly to the coupling device so that the spinal rod is positioned between the coupling device and a reducing member of the rod reducing assembly;

shifting the rod reducing member into contact with the spinal rod so that the rod reducing member contacts the spinal rod at a plurality of spaced points;

applying force to the rod reducing member to shift the spinal rod into the coupling device;

driving a cap member into locking engagement with the coupling device at a point intermediate the plurality of spaced contact points between the rod reducing member and spinal rod.

9. The method of claim 8 further comprising rotating a drive mechanism to shift the rod reducing member.

10. The method of claim 8 further comprising linearly shifting the reducing member to contact the spinal rod, engaging the reducing member with a drive mechanism, and then using the drive mechanism to shift the spinal rod into the coupling device.

11. The method of claim 8 further comprising releasably coupling the cap member to an elongate drive member, shifting the elongate drive member linearly toward the coupling device to secure the cap to the coupling device, disengaging the cap member from the drive member, and retracting the drive member away from the coupling device.

12. The method of claim 11, wherein the drive member is first shifted to a provisional lock position where the cap releasably coupled thereto is shifted partway into the coupling device and secured thereto, and subsequently shifted to a full lock position where the cap is shifted fully into the coupling device to immobilize the rod in the coupling device.

13. The method of claim 11, further comprising securing the drive member to the reducing member prior to shifting the drive member linearly.