ROD REDUCER APPARATUS FOR SPINAL CORRECTIVE SURGERY

• US 20120271365A1
• Filed: 12/08/2009
• Published: 10/25/2012
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Synthese USA LLC
• Inventors: Daubs, Michael, Rathbun, David, Dec, Brian
• Granted Patent: US 9,161,788 B2
• Time in Patent Office: Days
• US Class Current: 606/86.A
• CPC Class Codes: A61B 17/7085 for insertion of a longitudinal element down one or more hollow screw or hook extensions, i.e. at least a part of the element within an extension has a component of movement parallel to the extension's axis
• 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

Spinal rod reduction apparatuses, systems, and methods are provided. In various examples, a rod reduction apparatus includes a first threaded member (130, 210, 330) including an engagement feature (138A, 138B, 220, 332, 334) configured to selectively anchor the first threaded member to the implantable screw assembly. A second threaded member (110, 230, 310) is configured to threadably engage with the first threaded member. The second threaded member is axially movable with respect to the first threaded member with rotation of the second threaded member. A spinal rod urging member (120, 240, 320) is axially movable with the second threaded member. The urging member includes a bearing surface (126, 242, 320) that is configured to selectively abut the spinal rod and selectively urge the spinal rod toward the implantable screw assembly with rotation of the second threaded member in a first rotational direction.

Claims

1. An apparatus configured to selectively engage with a spinal rod and an implantable screw assembly, the apparatus comprising:

a first threaded member including first threads around at least a portion of an outer surface of the first threaded member, the first threaded member including an engagement feature configured to selectively anchor the first threaded member to the implantable screw assembly;

a second threaded member including second threads around at least a portion of an inner surface of the second threaded member, the second threaded member configured to threadably engage with the first threaded member, the second threaded member being axially movable with respect to the first threaded member with rotation of the second threaded member; and

a spinal rod urging member axially movable with the second threaded member, the urging member including a bearing surface that is configured to selectively abut the spinal rod and selectively urge the spinal rod toward the implantable screw assembly with rotation of the second threaded member in a first rotational direction.

2. The apparatus of claim 1, wherein the engagement feature includes at least one protrusion configured to mate with a corresponding number of receptacles of the implantable screw assembly.

3. The apparatus of claim 1, wherein the engagement feature includes a grasping element configured to selectively couple to a proximal end of the implantable screw assembly.

4. The apparatus of claim 1, wherein the engagement feature is disposed at a distal end of the first threaded member.

5. The apparatus of claim 1, wherein the urging member is coupled to the second threaded member.

6. The apparatus of claim 1, wherein the first threaded member is substantially tubular and includes a first leg and a second leg, the first and second legs extending substantially axially, wherein distal ends of the first and second legs are configured to be selectively radially separable.

7. The apparatus of claim 6, wherein the first and second legs are substantially semi-circular in cross section.

8. The apparatus of claim 7, wherein the first and second legs of the first threaded member are held together by the second threaded member threadably engaged around the outer surface of the first threaded member.

9. The apparatus of claim 8, wherein the outer surface of the first threaded member includes a portion of decreased diameter configured to allow the first and second legs to selectively radially separate with the first threaded member threadably engaged with the second threaded member.

10. The apparatus of claim 6, wherein the first threaded member includes a gap between the first leg and the second leg, the gap being configured to accommodate the spinal rod.

11. The apparatus of claim 10, wherein the bearing surface of the urging member is disposed at least partially within the gap between the first leg and the second leg.

12. The apparatus of claim 1, wherein the second threaded member includes a tool engagement portion configured to engage with a tool configured to rotate the second threaded member with respect to the first thread member.

13. The apparatus of claim 12, wherein the tool engagement portion includes a recess including a drive surface configured to mate with the tool.

14. The apparatus of claim 12, wherein the tool engagement portion includes a nut configured to mate with the tool.

15. The apparatus of claim 14, wherein the nut includes a hex nut.

16. The apparatus of claim 1, wherein the spinal rod urging member includes a claw element including one or more arms, each arm including the bearing surface configured to selectively abut the spinal rod.

17. The apparatus of claim 16, wherein the bearing surface of each arm is disposed at an end of the arm.

18. The apparatus of claim 16, wherein the bearing surface includes a rod recess.

19. The apparatus of claim 1, wherein the engagement feature of the first threaded member includes a grasping element configured to couple to an underside of a head of the implantable screw assembly.

20. The apparatus of claim 1, wherein the second threaded member includes a gripping surface configured to grip during manual rotation of the second threaded member with respect to the first threaded member.

21. A method comprising:

placing at least one rod reducer along a spinal rod and substantially in alignment with at least one pedicle screw, wherein placement of the rod reducer along the spinal rod includes substantially aligning a bearing surface of a spinal rod urging member of the rod reducer with the spinal rod;

engaging the rod reducer with the pedicle screw;

incrementally actuating the rod reducer to gradually reduce the spinal rod into engagement with the pedicle screw, wherein actuation of the rod reducer causes movement of the bearing surface toward the pedicle screw to urge the spinal rod toward the pedicle screw; and

engaging the pedicle screw with the spinal rod.

22. The method of claim 21, wherein engaging the pedicle screw with the spinal rod includes attaching a locking cap to the pedicle screw to retain the spinal rod in engagement with the pedicle screw.

23. The method of claim 21, comprising removing the rod reducer from the pedicle screw after engagement of the pedicle screw with the spinal rod.

24. The method of claim 23, comprising cleaning the rod reducer for reuse after removal of the rod reducer from the pedicle screw.

25. The method of claim 21, wherein placing the at least one rod reducer along the spinal rod includes placing two or more rod reducers along the spinal rod and substantially in alignment with two or more pedicle screws.

26. The method of claim 21, comprising:

placing the spinal rod along a plurality of pedicle screws;

engaging, without using a rod reducer, the spinal rod to one or more pedicle screws for which no spinal rod reduction is necessary; and

engaging, using one or more rod reducers, the spinal rod to one or more pedicle screws for which spinal rod reduction is necessary.

27. The method of claim 21, wherein engaging the rod reducer with the pedicle screw includes manually engaging the rod reducer with the pedicle screw.

28. The method of claim 21, wherein engaging the rod reducer with the pedicle screw includes engaging the rod reducer with the pedicle screw using a tool configured to mate with a tool engagement portion of the rod reducer.

29. A spinal rod reduction system comprising:

a spinal rod;

a plurality of pedicle screws configured to engage with the spinal rod; and

a plurality of rod reducers, each rod reducer including;

a first threaded member including first threads around at least a portion of an outer surface of the first threaded member, the first threaded member including an engagement feature configured to selectively anchor the first threaded member to the pedicle screw;

a second threaded member including second threads around at least a portion of an inner surface of the second threaded member, the second threaded member configured to threadably engage with the first threaded member, the second threaded member being axially movable with respect to the first threaded member with rotation of the second threaded member; and

a spinal rod urging member axially movable with the second threaded member, the urging member including a bearing surface that is configured to selectively abut the spinal rod and selectively urge the spinal rod toward the pedicle screw with rotation of the second threaded member in a first rotational direction.

30. The spinal rod reduction system of claim 29, wherein the rod reducers are configured to engage with the pedicle screws and the spinal rod at locations where the spinal rod is spaced from the pedicle screws.

31. The spinal rod reduction system of claim 29, wherein the plurality of rod reducers are configured to incrementally urge the spinal rod toward the plurality of pedicle screws.

32. The spinal rod reduction system of claim 29, comprising a locking cap configured to engage with the pedicle screw and retain the spinal rod in engagement with the pedicle screw.

33. The spinal rod reduction system of claim 29, comprising a tool configured to mate with a tool engagement portion of each of the rod reducers, the tool being configured to rotate the second threaded member with respect to the first thread member.

34. The spinal rod reduction system of claim 33, wherein the tool engagement portion includes a recess including a drive surface configured to mate with the tool.

35. The spinal rod reduction system of claim 33, wherein the tool engagement portion includes a nut configured to mate with the tool.

36. A spinal rod reduction assembly comprising:

one or more pedicle screws engaged with one or more vertebrae;

a spinal rod substantially aligned with the one or more pedicle screws; and

at least one rod reducer removably engaged with at least one pedicle screw at a location where the spinal rod is spaced by a distance from the pedicle screw, the rod reducer including a spinal rod urging member axially movable with respect to the rod reducer, the urging member including a bearing surface that is configured to selectively abut the spinal rod and selectively urge, with actuation of the rod reducer, the spinal rod toward the pedicle screw to decrease the distance between the spinal rod and the pedicle screw.