INSERTION AND REDUCTION TOOL FOR PEDICLE SCREW ASSEMBLY

• US 20100137875A1
• Filed: 10/14/2009
• Published: 06/03/2010
• Est. Priority Date: 10/14/2008
• Status: Active Grant

• Current Assignee: Trinity Orthopedics, LLC
• Original Assignee: Trinity Orthopedics, LLC
• Inventors: Marino, James F., Elbanna, Jamil
• Granted Patent: US 8,460,308 B2
• Time in Patent Office: Days
• US Class Current: 606/104
• CPC Class Codes: A61B 17/7002 Longitudinal elements, e.g. rods
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 17/7038 to a different extent in different directions, e.g. within one plane only
• CPC Class Codes: A61B 17/7076 for driving, positioning or assembling spinal clamps or bone anchors specially adapted for spinal fixation
• 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

Disclosed are devices, methods and systems for manipulating a pedicle screw assembly and for inserting and reducing a rod relative to the pedicle screw assembly. The system can include a cannula assembly having a reduction cannula with an internal bore extending between a proximal region and a distal region and an insertion cannula co-axially positioned within the internal bore of the reduction cannula. The insertion cannula includes a pair of opposed prongs extending distally from a distal region of the insertion cannula, wherein each prong is interposed between a pair of flexible projecting elements. The pair of opposed prongs of the insertion cannula and the distal region of the reduction cannula are aligned to collectively define an opening that is sized and shaped for receiving a spinal rod. The device also can include an annular collar mounted on the proximal region of the reduction cannula and rotatably coupled to a proximal region of the insertion cannula. The cannula assembly can also be a pivoting cannula assembly.

Claims

1. A spinal rod insertion and reduction device, comprising:

a cannula assembly, comprising;

a reduction cannula having an internal bore extending between a proximal region and a distal region; and

an insertion cannula co-axially positioned within the internal bore of the reduction cannula, wherein the insertion cannula comprises a pair of opposed prongs and at least one flexible projecting element extending distally from a distal region of the insertion cannula, wherein the pair of opposed prongs of the insertion cannula and the distal region of the reduction cannula are aligned to collectively define an opening that is sized and shaped for receiving a spinal rod.

2. The device of claim 1, further comprising an annular collar mounted on the proximal region of the reduction cannula and rotatably coupled to a proximal region of the insertion cannula.

3. The device of claim 2, wherein rotation of the collar imparts relative linear movement between the insertion cannula and reduction cannula along a long axis of the cannula assembly.

4. The device of claim 3, wherein relative linear movement between the insertion cannula and reduction cannula provides gradual and forceful translation of the reduction cannula distally along the long axis of the cannula assembly.

5. The device of claim 2, wherein the collar is mounted to the reduction cannula via a slip plane that permits the collar to rotate about the reduction cannula.

6. The device of claim 2, wherein the collar has internal threads that rotatably couple to threads on the proximal region of the insertion cannula.

7. The device of claim 1, wherein the opposed prongs are configured to insert into a pair of longitudinal channels on an external surface of a fixation device receiver element.

8. The device of claim 7, wherein the flexible projecting element is radially displaceable.

9. The device of claim 8, wherein the projecting element comprises a flange on an internal surface that engages a slot intersecting the longitudinal channel upon insertion of the prong into the channel.

10. The device of claim 9, wherein the reduction cannula stabilizes the opposed prongs and confines the projecting element to prevent dissociation of the insertion cannula from the receiver element.

11. The device of claim 1, wherein dimensions of the cannula assembly along a first axis is less than dimensions of the cannula assembly along a second axis perpendicular to the first axis.

12. The device of claim 1, further comprising a disengagement tool, the tool comprising an actuation handle, a cannula assembly coupler configured to couple the disengagement tool to the cannula assembly, and an elongate arm comprising a distal control element.

13. The device of claim 12, wherein the elongate arm inserts through an internal bore of the insertion cannula and the cannula assembly coupled is coupled at a proximal end to the cannula assembly.

14. The device of claim 12, wherein the distal control element comprises an opening configured to receive and hold a compression nut.

15. The device of claim 14, wherein the control element comprises one or more displacing elements that sequentially splay the projecting element radially outward and push downward on an upper surface of the compression nut while simultaneously engaging the internal bore of the insertion cannula to disengage the insertion cannula from the receiver element.

16. The device of claim 15, wherein the disengagement tool applies negligible net force to the receiver element during disengagement of the insertion cannula from the fixation device receiver element.

17. The device of claim 1, wherein the reduction cannula comprises one or more visual markers on an outer surface.

18. The device of claim 17, wherein the one or more markers are selected from the group comprising a channel, a slot and indicia.

19. The device of claim 17, wherein the marker comprises an external longitudinal trough through which a distal tapered tip of the spinal rod can be translated distally during insertion through the opening.

20. The device of claim 1, wherein the insertion cannula comprises a proximal pivoting component and a distal coupling component connected by a pivoting hinge.

21. The device of claim 1, wherein the distal region of the reduction cannula has a vaulted leading edge.

22. A method of inserting and reducing a spinal rod into a fixation device assembly, comprising:

providing a fixation device assembly comprising a fixation device engaged with a bone and a rod receiver element having an outer surface comprising a pair of opposed longitudinal channels, each channel intersected cross-wise by a slot;

coupling a cannula assembly to the receiver element, the cannula assembly comprising;

a reduction cannula having an internal bore extending between a proximal region and a distal region; and

an insertion cannula co-axially positioned within the internal bore of the reduction cannula, wherein the insertion cannula comprises a pair of opposed prongs and at least one flexible projecting element extending distally from a distal region of the insertion cannula, wherein the pair of opposed prongs of the insertion cannula and the distal region of the reduction cannula are aligned to collectively define an opening that is sized and shaped for receiving a connecting rod;

sliding the prongs of the insertion cannula into the longitudinal channels of the receiver element, wherein the flexible projecting element temporarily splays outward and subsequently recoils into engagement with the slots intersecting the longitudinal channels as the prongs slide into the channels;

inserting the connecting rod into the opening; and

moving the reduction cannula distally toward the fixation device while the insertion cannula maintains the fixation device assembly in a desired position.

23. The method of claim 22, wherein the distal region of the reduction cannula has a vaulted leading edge.

24. The method of claim 23, wherein moving the reduction cannula distally comprises pushing the connecting rod into the receiver element with the vaulted leading edge of the reduction cannula.

25. The method of claim 22, wherein moving the reduction cannula comprises rotating an annular collar mounted on the proximal region of the reduction cannula and rotatably coupled to a threaded proximal region of the insertion cannula to impart linear translation between the reduction cannula and the insertion cannula.

26. The method of claim 22, wherein moving the reduction cannula comprises providing gradual and forceful linear translation of the reduction cannula distally along a long axis of the cannula assembly.

27. The method of claim 22, further comprising deploying a compression nut into the receiver element to fixate the connecting rod relative to the fixation device assembly.

28. The method of claim 27, wherein deploying the compression nut comprises using a tool comprising:

an actuation handle;

a cannula assembly coupler element configured to couple the tool to the cannula assembly; and

an elongate arm comprising a distal control element.

29. The method of claim 28, wherein the distal control element comprises an opening configured to receive and hold the compression nut.

30. The method of claim 28, wherein using the tool comprises inserting the elongate arm through an internal bore of the insertion cannula.

31. The method of claim 30, further comprising using the distal control element of the tool to sequentially splay the projecting element radially outward and push downward on an upper surface of the compression nut while simultaneously engaging the internal bore of the insertion cannula to disengage the insertion cannula from the receiver element.

32. The method of claim 31, wherein using the tool to disengage the insertion cannula from the receiver element applies negligible net force to the receiver element.

33. The method of claim 22, wherein inserting the connecting rod comprises translating a distal tapered tip of the connecting rod distally within a longitudinal trough positioned along an outer surface of the reduction cannula.

34. A spinal rod insertion and reduction device, comprising:

a reduction cannula having an internal bore extending between a proximal region and a distal region; and

an insertion cannula co-axially positioned within the internal bore of the reduction cannula and comprising a joint having a pivot axis that is transverse to a long axis of the insertion cannula, wherein the joint couples together a proximal, articulating element to a distal cannula element such that the proximal, articulating element pivots about the pivot axis along a single plane.

35. The device of claim 34, wherein the joint comprises a pinned joint.

36. The device of claim 35, wherein the pinned joint comprises one or more hinge pins extending through a first pair of opposed apertures near a distal region of the proximal, articulating element and a second pair of opposed apertures near a proximal region of the distal cannula element, wherein the first and second pairs of opposed apertures are aligned.

37. The device of claim 34, wherein the proximal, articulating element pivots between about 30 degrees caudal and 30 degrees cephalad from the long axis of the insertion cannula.

38. The device of claim 34, wherein the distal cannula element includes a pair of opposed prongs and at least one flexible projecting element extending distally from the distal cannula element.

39. The device of claim 38, wherein the pair of opposed prongs of the insertion cannula and the distal region of the reduction cannula are aligned to collectively define an opening that is sized and shaped for receiving a spinal rod.

40. The device of claim 39, wherein the opposed prongs are configured to insert into a pair of longitudinal channels on an external surface of a fixation device receiver element.

41. The device of claim 40, wherein the flexible projecting element is radially displaceable.

42. The device of claim 41, wherein the projecting element comprises a flange on an internal surface that engages a slot intersecting the longitudinal channel upon insertion of the prong into the channel.

43. The device of claim 34, further comprising an annular collar mounted on the proximal region of the reduction cannula.

44. The device of claim 43, wherein the annular collar is rotatably coupled to a proximal region of the insertion cannula.

45. The device of claim 44, wherein rotation of the collar imparts relative linear movement between the insertion cannula and reduction cannula along the long axis of the insertion cannula.

46. The device of claim 45, wherein relative linear movement between the insertion cannula and reduction cannula provides gradual and forceful translation of the reduction cannula distally along the long axis of the insertion cannula.

47. The device of claim 46, wherein the collar is mounted to the reduction cannula via a slip plane that permits the collar to rotate about the reduction cannula.

48. The device of claim 46, wherein the collar has internal threads that rotatably couple to threads on the proximal, articulating element.